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Electric Vehicle Home Charging

Update 2020

Charging your electric car at home or work.

Electric vehicle home charging for small electric cars is feasible at home or at work from a 15 amp power point. A power cable plugs into the car’s on-board charger. Most such vehicles have a charging unit inbuilt.

Some electric car dealers include a home charging assessment price and/or a consultation with a licensed electrical contractor as part of the car’s purchase price.

A typical electric of hybrid used for typical commuting (of 40-50 km a day) uses 2.5-5.0 kilowatt/hours. This, often called one 'unit’, usually costs less during off-peak periods .

This guide gives some indication of how many kilometres you can drive when charging typical electric cars from a home or similar supply at their maximum rate via that inbuilt charger.

Type:                               Maximum charge  (kW).  km per hour of charging

BMW i3                             7.4             25

Chevy Spark EV               3.3             11

Fiat 500e                          6.6             22

Ford Focus Electric          6.6             22

Kia Soul EV                      6.6             22

Mercedes B-Class Elec.  10               29

Mitsubishi i-MieEV           3.3              11

Nissan Leaf                     3.3 – 6.6     11 – 22

Smart Electric Drive         3.3             11

Tesla Models S & X         10 -20        29-58

Charging is readily done overnight but solar captured during the day can be sold to the electricity supplier.

Electric vehicle home charging - electricity costs (in 2020) across Australia.

Average prices (per kilowatt/hour) are:

Queensland: 22.72 cents

Victoria: 24.20 cents

New South Wales: 26.245 cents

South Australia: 36.223 cents

Tasmania 32.137 cents

Western Australia 28.8 cents

Most suppliers charge about 25 cents per kilowatt hour (off-peak). Even if not using solar it will cost only a dollar or two a day to travel the average daily 40-50 km to and from work. This is far less than for even small petrol-fuelled cars. Most use at least 5 litres per 100 km – typically costing (in mid 2020) about $7.

Meters for electric vehicle charging

You are likely to need an additional meter for a dedicated electric car charging tariff. It may also be necessary to have an electric charging point set up by your electrical contractor. You can save money if you switch to an economy tariff for off peak charging overnight. To be on an economy tariff, you must have a hard-wired dedicated EV charging point. A standard electrical power point isn't permitted as it does not take long to work out that’s a cheap source also for other purposes!

Electric vehicle home charging - charging from solar

If you charge from a home solar system you have added benefit of no CO2 emissions from this renewable energy source. That required will be the maximum 6.6 kW systems that currently enable rebates. Solar modules, however, are now so cheap that it is feasible to forgo that rebate.

Electric vehicle home charging - home charging set-up cost

The cost of home charging from grid power primarily varies with local electricity price tariff and charging options.

A Victorian electric vehicle report noted that installing a home charging outlet costs around $1,750 for the charging circuit wiring, plus <$100 for a standard electrical power point, up to $500 for a basic dedicated EV charging unit and up to $2500 for a more advanced such unit.

If your choice of charging rate exceeds the standard fuse or circuit breaker rating, those too must be upgraded – but that cost is not high. A licensed electrical contractor can advise re all this.

Before going too far check the varying electricity tariffs for electric vehicle charging, already offered by many electricity suppliers.

If solar power is to be used, in urban areas this is likely to best done by feeding into the grid and buying it back at off-peak rates.  Here again – see Electric vehicles – solar charging. 

Charging at public charging outlets

An ever-increasing range of service station fast and super-fast chargers charge at rates as high as 135 kW. They can already fully recharge an EV battery in around 30 minutes. In practice, owners will use these only during long drives – and rely on routine charging at home and whilst at work. Electric car vendors too offer this.

There are already fast charging facilities around Australia – including right across the Nullabor.

See: Charge Stations in Australia (https://myelectriccar.com.au/charge-stations-in-australia) or ChargePoint. Prices vary from state to state etc – much as does petrol right now.

Many existing home grid-connect solar systems have excess capacity outside peak periods. Solar energy fed in during the day can be re-drawn during off-peak periods, for much the same price, to charge an electric car. This is because many grid networks have excess capacity outside peak periods. Furthermore, such charging extends battery life: all dislike ongoing deep discharges.

Summary

It is already totally feasible to charge cars from home and office solar. Moreover, it is being done by many owners right now.

Electric Vehicle History

Updated 2020

Electric vehicle history

Electric vehicles have existed for longer than most people think. They long pre-date petrol and diesel. This electric vehicle history by Collyn Rivers is an overview.

The first dc electric motor (1866). Pic: Siemens UK.

The electric battery was invented by Allessandro Volta in 1800. In 1820, Christian Oersted showed electricity could produce a magnetic field. William Sturgeon, (in 1825) invented the electromagnet. Inventors worldwide sought to build an electric motor. They used two main approaches. These were: rotating, or reciprocating (i.e. like early steam engines).

In 1834, Moritz Jacobi invented the first (realistically powerful) electric motor. By 1838 it was improved. It propelled a 14-passenger boat. Meanwhile (1835), Sibrandus Stratingh and Christopher Becker developed an electric motor. It drove a small model carriage. The first electric motor patent was granted to USA’s Thomas Davenport. Many US sources credit Davenport as ‘inventing’ the electric car. It was, however, only a small model. It had negligible power. In 1866, Werner von Siemens developed the basic DC motor. It was this that enabled the first electric cars. DC motors are used to this day.

Electric vehicles were also hampered by lack of stored energy. The only realistic source required constantly supplied diluted acid. These ‘batteries’ were like today's fuel cells. They combined hydrogen and oxygen to produce electricity. Such batteries worked. There is no record, however, of their powering electric vehicles.

The first lead-acid batteries

In 1859, Gaston Plante developed practical lead-acid batteries. They were bulky and heavy. Nevertheless, they made electric vehicles practical. Their first known usage (1897) was in New York's electrically-powered taxis.

The first electric powered taxi – New York late 1890s. Pic: taxifarefinder.com

Electric cars’ original acceptance was thus near the end of the 1800s. Most were quieter and smoother than early petrol-fueled cars. Electric cars started instantly. They needed no ‘warming. No gear changing was required. There were even hybrids. In 1916, the Woods Motor Vehicle Company developed a car with both petrol and electrical engines. See Electric Vehicles – Hybrids.

The electric vehicle market was primarily the USA. There was, however, some usage in Europe. London had electrically-powered taxis from 1897. They became known as ‘Hummingbirds’ – due their curious sound.

A London Hummingbird electric taxi – in use from 1897 for many years. They were designed by Walter Bersey.

End of an era

Electric vehicles of that era lacked adequate control technology. This limited speed to about 30 km/h (about 19 mph).

By 1920 or so, road structures (particularly the USA's) had massively increased. This was particularly inter-city. This required a vehicle range beyond that from batteries. These, however, remained similar in weight and size as 80 years before. Moreover, recharging facilities were inadequate beyond urban areas.

Meanwhile petroleum became increasingly plentiful. This enabled it to power vehicles cheaper and further than electrically. Furthermore, mass production made them affordable. The result was Henry Ford’s (1908) mass-produced model-T. It killed sales of electric cars. Thereon, electric vehicles were used only where limited range was required. It was nearly 40 years before electric cars re-appeared.

In the late 1950s, Henney Coachworks and Exide Batteries developed an electrically-powered Renault Dauphine. It attracted some sales. It could not, however, compete in price with conventional cars. Production ceased in 1961.

General Motors EV1

In 1990 California's Air Resources Board briefly re-ignited interest in electric cars. Its mandate required U.S. major vehicle makers to have 2% of their products totally emissions-free if used in California. This resulted in General Motors producing its EV1. It was an electric-ony car.

Early EV1s had 16.5–18.7 kWh lead-acid batteries. Later EV1s had 26.4 kWh Nickel Metal Hydride (NiMH) batteries. The car was produced from 1996 to 1999. It was the first mass-produced and purpose-designed electric vehicle of the modern era.

Usage was by leasing only. Customers liked the EV1, but General Motors saw electric vehicles as unprofitable. It sought to cease production. In 2002 EV1 usage was ceased. General Motors repossessed all of them. Most were crushed. A few were given to museums, but with deactivated motors. The Smithsonian Institution has the only intact EV1.

Major US car makers then legally questioned California's emissions requirement. This resulted in relaxed obligations. That, in turn, enabled developing and producing low emissions vehicles. These included natural gas and hybrid engines, but not (then) electric-only.

The General Motors EV1. Pic: Wikipedia

The right concept at the wrong time

The electric car (and truck) back then was the right concept. But at the wrong time. It awaited control technology, and lighter and smaller batteries.

Control technology then improved dramatically. That of rechargeable batteries, however, did not. Moreover, the size, weight and energy stored in lead-acid batteries remained much as 100 years before.

In 1996, the University of Texas conceived the lithium battery. These store three to four times the energy as lead-acid batteries the same size and weight. They charge quickly and can release huge amounts of energy over a short time.

Now (late 2020), lithium batteries enable electric-only cars to travel 350-550 km (about 220-345 miles) between charges. This is still borderline. It is inevitable, however it is inevitable that battery technology will advance. One thousand kilometres (625 miles) is now seen as feasible. Moreover, so too are electric off-road vehicles.

Further information

It is feasible to use home and other solar (with or without grid-connect) to charge electric cars. For details on using solar to charge electric cars click here. Furthermore, articles on all aspects of electrics cars are being progressively published on this website. Moreover, these will include ongoing details of technology and charging.

Electric Vehicle Motors

Updated 2020

Electric vehicle motors

AC/DC

Electric vehicle motors use one or other of the two main kinds of electricity: alternating current and direct current. Both are effective as electric vehicle motors.

Alternating Current (AC) is where electric current constantly reverses its direction. It is that used in grid power supplies. In Australia and many other countries it cycles at 50 times a second. In America it cycles at 60 times a second.

Tesla Roadster AC motor. Pic: Tesla.

The AC induction motors used in a few electric vehicles have a stator (stationary coils of wire). When AC current flows through it, the stator generates a rotating magnetic field. That in turn causes a rotatable armature to revolve. It rotates at the rate of the AC current: i.e. at 50 or 60 times a second.

The relationship between AC voltage and its frequency enables changes in vehicle speed. The batteries' DC output is converted to AC by an ‘inverter’. All that required is an inverter that has variable frequency. This is effective, but not that efficient.

AC induction motors are often used in hybrid vehicles. These use electric drive for limited commuting. Efficiency and range are not seen as major factors. There is however an increasing trend to direct current (DC) motors for electric vehicles.

Electric Vehicle Motors -  Direct Current (DC)

Direct current (DC) is a flow of electrons in one direction. Edison is often credited as conceiving it. It was, however, initially conceived (in 1800) by Alessandro Volta. The term 'Volt' commorates his name.

A basic DC motor has fixed external magnets. These surround a revolving armature that is an electromagnet. It also doubles as the drive shaft. Direct current is fed to this electromagnet via a commutator.

Electric Vehicle Motors - commutators & brushes

The commutator is a basic DC motor's weak point. It is a small ‘drum’ made of an electrically-insulating material. This drum has a number of copper segments. Carbon brushes, that conduct the DC current, are sprung against these segments.

The direct current is fed to the revolving armature via those brushes. This creates a magnetic field in the armature. The magnetic field causes the armature to spin through 180 degrees. A further mechanism causes the current fed to the brushes to reverse the DC’s polarity for the second 180 degrees. And so on.

While these motors work well, the carbon brushes sprung against rotating segments, wear out. They also constantly spark. This is a potential fire hazard. Moreover, it causes electrical 'noise' that must be suppressed.

A few electric vehicles use basic DC motors originally designed for other purposes. There are, however, many variants that combine the benefits of both AC and DC.

A DC electric motor’s commutator. One carbon brush is attached to the yellow lead. A second (out of sight) is on the left.

Brushless DC motors

A Brushless DC motor (BLDC), is in effect a DC motor turned inside out. It has permanent magnets on the rotor that generate a rotatable magnetic field on its outside. An electronic sensor monitors the angle of the rotor. Then, via high power transistors, it applies current to generate an external electromagnetic field. That field creates a turning force.

Brushless DC motor – Pic: original source unknown

Maximum torque at zero speed

Brushless DC motors develop maximum torque at zero speed. They are efficient electrically. Moreover, they have no brushes that wear out, and no need for internal cooling. Furthermore, this enables its internal bits and pieces to be free of contamination.

These motors produce far more torque than fossil-fuelled motors of comparable size and/or weight. They can rotate at far greater speed. They are relatively light and compact. Their available power is primarily limited by heat.

BLDC motors have minor downsides. They cost more to make than their brushed counterparts. Furthermore, d at present, the permanent magnets field strength is not adjustable. Work is in progress to make it so. Once achieved that will enable increasing maximum torque at low speeds when required. This is likely to be done by using neodymium (NdFeB) magnets.

Brushless DC motors cost more than most electric motors but are nevertheless proving commercially successful. They are used for Tesla’s Model 3. It seems likely they will dominate the market.

Electric vehicle efficiency & emissions

Updated 2020

Electric Vehicle Efficiency & Emissions

This article, by Collyn Rivers, discusses electric vehicle efficiency and emissions. All road vehicles emit pollution (and are health issues). Emissions are in two main forms. One includes haze and particulate matter. The other are 'greenhouse gases’, These include carbon dioxide and methane.

Vehicle pollution – 2019. Pic: Original source unknown

Particulate matter from tyres

Tyres constantly shed particulate matter. It is mainly soot and styrene-butadiene. The smaller particulates are airborne. They are a minor cancer risk. https://ncbi.nlm.nih.gov/pmc/articles/PMC1567725/.

The larger particles are washed into lakes and rivers etc. Related data, however, is scarce. Sweden, calculates tyre particulates as about 150 tonnes yearly. Battery-electric vehicles are heavier than those fossil-fuelled. Their tyre emissions accordingly increase.

Particulate matter from brake linings

Brake linings cause particulate emissions. These were initially asbestos cadmium, copper, lead, and zinc. All are now banned. They are now fibres of glass, steel and plastic. There are also antimony compounds, brass chips and iron filings. Also steel wool to conduct heat. These particulates disperse directly into the air. Their antimony (Sb) content may increase cancer. Most electric vehicles reduce speed by regenerative braking. This reduces brake lining emissions.

Regenerative braking

Many hybrid and most electric cars have regenerative braking. When needing to slow or stop your car's drive motor acts as a generator. This charges the vehicle’s batteries.

Regenerative braking assists thermodynamic efficiency in all electric vehicles. Not just hybrids. It also reduces braking emissions.

Regenerative braking: whilst braking the drive motor acts as a generator, thereby charging the vehicle’s batteries. By doing so the vehicle’s kinetic energy is saved and stored for propulsive use. Pic: reworked from a concept of the Porter & Chester Institue, Connecticut, USA.

Tailpipe emissions

Electric vehicles produce negligable direct emissions. Hybrids produce no tailpipe emissions in electric mode. They have evaporative emissions, mainly during refueling. Their overall emissions are lower than those of 100% fossil-fuelled vehicles.

Indirect emissions from fossil-fuelled power stations 

An Australian electricity power station. Pic: SMH.com.au.

Electric vehicles run from grid power must include power station emissions. Most of Australia’s power stations are fossil-fuelled. At an averaged 920 kg CO2-per megawatt/hour, ost are below average global efficiency. None rivals China's 670–800 kg per megawatt/hour. India has many inefficient fossil-fuelled power stations, but is the world-leader of large-scale solar power. No fossil-fuelled power station, however, converts more than 40% of heat into electricity.

Some 78% per cent of the electricity generated by Australia's power stations is from coal. Gas accounts for just under 10%. The remaining 12% or so is from hydro, wind and solar.

Due to Australia's power stations emissions, it seems pointless to use an electric car powered via the grid network. When battery capacity permits, however, it makes sense to go all electric. This particularly if charged via solar. Or possibly via hydrogen fuel cells.

Future power stations

Australia is unlikely to build efficient fossil-fuelled power stations. Even reducing their existing pollution is enormously costly. Their output will inevitably be undercut by renewable energy. Wind plus solar and hydro systems are cheaper and simpler. Furthermore, (once apart from manufacturing and erecting) wind, solar and hydro is pollution free.

Quantifying petrol vehicle emissions

Oil-well to vehicle emissions must include extracting, refining and distributing. Furthermore, fossil fuel powered vehicle engines are about 25% or so efficient. The remaining 75% of the energy is lost.

Overall, every litre of burned petrol causes in 3.15 kg of CO2 emissions. About 81% is caused in burning the petrol, 13% by extraction and transportation, and around 6% from refining. Burning petrol's released nitrous oxide has 300 times the global warming potential of CO2.

A typical fossil-fuelled Australian passenger car uses about 9.0 km/litre. Driving just one kilometre generates close to 350 grams of CO2 equivalent being emitted into the atmosphere. This is about 4.8 tonnes of CO2 equivalent emissions per car per year.

European disgrace

Some major European vehicle makers disgracefully concealed their diesel engine emissions. They included software that detected the vehicle's emission were being checked. That software changed the engine's operating mode accordingly to indicate reduced emissions.

Huge technical efforts have since been made to legimately limit fossil-fuel powered vehicle emissions. It is now, however, recognised it is not feasible to reduce them any further. This is particularly so of diesel. Reduced vehicle weight and performance assists but vehicle makers globally are now (2020) accepting their post-2030 products will be all-electric.

Current battery technology restricts range between charging. All-electric cars are fine for typical commuting to and from work. For general use right now however, hybrids make more sense.

Most cars are driven about 14,000 km/year. They emit about 4.8 tonne/year. The Toyota Prius hybrid averages just under 30 km/litre. It emits 31% CO2 (about 1.5 tonnes a year). That is 3.3 tonnes less than a comparable petrol-powered car.

Toyota Prius Hybrid. Pic: Toyota

Hydrogen

An increasing possibility is that hydrogen may replace oil as a global source of fuel. It can and is already being produced from fossil fuel. It can be done (and on a large scale) by passing an electric current through water. This now includes sea water. This enables it to be produced via both solar, wind-power and wave-power.

A so-called fuel cell enables hydrogen to be re-converted to electricity stored in so-called fuel cells. The fuel cell can then power an electric vehicle. This is not just conjecture. Many such vehicles now exist - mainly in California and Norway.

Australia’s main power stations - ages and emissions

Those known in terms of year built, and kilograms of CO2 per megawatt/hour (MWh) actually produced.

Stanwell (1996): 969 kg per MWh.

Bluewaters (2009): 982 kg per MWh.

Muja CD (1985): 982 kg per MWh.

Mt Piper (1996): 997 kg per MWh.

Collie (1999): 1004 kg per MWh.

Eraring (1982): 1011 kg per MWh.

Vales Point (1979): 1018 kg per MWh.

Callide B (1989): 1019 kg per MWh.

Bayswater (1986): 1031 kg per MWh.

Gladstone (1976): 1052 kg per MWh.

Lidell (1973): 1066 kg per MWh.

Muja AB (1969): 1285 kg per MWh.

Worsley (1982): 1324 kg per MWh.

A few of the above have now been (or soon will be) closed down.

Electric Vehicles Energy Use

Updated 2020

Electric vehicles energy use

Regardless of its type of fuel, the energy drawn by any road vehicle is a function of three main factors: air drag, accelerating and braking, and rolling resistance. Electric vehicles energy use is no exception.

The Tesla 3. Pic: Tesla

Air drag

This relates to frontal area and aerodynamics, and particularly to speed. The reason speed so matters is that energy use rises with the cube of the speed). It is thus also affected by driving into prevailing wind. This is not usually a major factor in most countries. It is, however, very much so on Australia’s 1675 km (141 miles) Eyre Highway. Often called the Nullarbor, the highway links South and Western Australia. It is very close to the ocean for much of the way. That wind tends to be either from in front or behind, and can be as high as 30-40 km/h. If driving into the 30 km/h wind at 90 km/h, for electric cars that’s a battery flattening equivalent 120 km/h.

Wind resistance is a powerful reason for driving anticlockwise around Australia. One drives north around September, around the top during winter, then back down the west coast and to where one started in late summer. This should result in a following wind for the west and east crossings.

Electric-only vehicles of today are most suited to urban driving. As battery technology inevitably advances, and charging facilities increase, these will be decreasing issues.

The (2016) Chevrolet Voltec electric vehicle motor and transmission. Pic: Chevrolet. 

Acceleration & braking

The energy involved in acceleration and braking relates substantially to the laden weight of the vehicle. Existing batteries are far heavier than their range-equivalent petrol or diesel. An electric vehicle motor and transmission, however, is simpler and lighter. Moreover, it is also 80% to 90% efficient (a fossil-fuelled engine is only 25%).

BMW i3 ultra-light carbon-fibre body shell saves weight. Pic: BMW.

Body shells can be made much lighter: BMW’s i3 electric car has an ultra-light carbon-fibre body shell. This cancels out much of the battery weight. That extra battery weight, however, is expected to be a short-term issue. As our article Electric Vehicle Batteries notes, huge efforts are in progress worldwide to reduce the weight of rechargeable batteries. This will also enable a longer range between recharging.

Rolling resistance

Rolling resistance is directly proportional to minor friction losses, minor heat loss due to tyre wall deflection (<3%), and speed. That of fossil-fuelled,and an electric vehicle’s rolling resistance, is thus the same. There is, however, one considerable energy advantage of electric (and hybrid) vehicle over internal-combustion engined vehicles. It of simple and effective regenerative braking. This recovers the kinetic energy that would be otherwise lost in heat-generating braking. It works by an electric car’s motor momentarily acting as a generator and charging the batteries.

Stop/starting in traffic

In recent years, petrol and diesel engine cars have a (usually optional) engine stop/starting system for use in congested traffic. Whilst this saves fuel, electrical energy is used for each restart. Moreover, electric cars will have a considerable edge as no energy is drawn whilst at rest, nor extra when restarting.

Electric Vehicle Hybrids

Updated 2020

Electric vehicle hybrids

Electric vehicle hybrids are powered by either or both electricity and fossil fuel. They are far from new. In 1898, Ferdinand Porsche developed a hybrid car (the Lohner-Porsche). Its petrol engine ran a generator powering electric motors in its front wheels. The car had a range of 60 km (about 37 miles) from batteries alone.

The 1898 Lohner-Porsche- the first hybrid car. Pic: Original source not known.

In 1905, American H. Piper applied for a patent for a petrol-electric hybrid vehicle. It was claimed to reach 40 km/h (25 mph) in ten seconds. The patent took a long time  before granting. By the time it was, petrol-fuelled vehicles achieved similar performance.

Woods Motor Company Dual Power 

The best-known early hybrid is the Woods Dual Power Model 44 Coupe. It was made from 1917-1918. The vehicle had four-cylinder 10.5 kW petrol engine. This coupled to an electric motor. The motor was powered by  115 Ah lead-acid batteries. Below 24 km/h (15 mph) the car ran from electricity. Above that, the petrol engine took over. Maximum speed was about 55 km/h (34 mph). Much like today's hybrid cars, it had regenerative braking. Reversing was by causing the electric motor to run backwards.

The Woods petrol-electric hybrid. Pic: courtesy of Petersen Automotive Museum Archives

The Woods car was promoted as having unlimited mileage, adequate speed and great economy. Also that it was faster than most electric cars. It was very costly. Only a few hundred were sold.

The first era of electric cars was ending. Whilst quieter, none could compete with Ford’s petrol Model T. Furthermore, battery development was static. Moreover, there was thus little incentive to develop electric motive power.

Hybrid revival

Hybrid development re-arose in the USA and Japan. Due to increasing air pollution, in 1966 the U.S. Congress recommended electric-powered vehicles. One (in 1969) was General Motors’ experimental hybrid. It used electric power to 16 km/h (10 mph). It then used electric and petrol power until 21 km/h (about 13 mph). From thereon it ran on petrol. Its maximum speed was about 65 km/h (about 40 mph).

The Arab oil embargo (1973) increased interest in electric powered vehicles. One result was Volkswagen’s experimental petrol/ battery hybrid. It was not, however, mass-produced. Another was the US Postal Service trialled battery-powered vans.

In 1976, the USA encouraged developing hybrid-electric components. Furthermore,Toyota built its first (experimental) hybrid. It used a gas-turbine generator to power an electric motor.

In 1980, lawn-mower maker Briggs and Stratton developed a hybrid car. It was driven by a twin cylinder 6 kW engine. It ran on ethanol, an electric motor, or both. Twin rear wheels bore 500 kg of batteries. It could travel 50 to 110 km (31-70 miles) in electric mode, and about 320 km in hybrid. The car was a promotion for the maker's lawn-mowers. To put it mildly, its adverse power/weight limited performance. Its reported time to reach 80 km/h (50 mph) in combined mode was 35 seconds. By comparison, even today's slowest cars need only a few seconds.

 

The Briggs and Stratton hybrid. Impressive visually –but seriously underpowered.

A battery boost

A major boost for hybrid vehicles was the USA’s (1991) ‘Advanced Battery Consortium’. It aimed at producing a compact battery. The US$90 million cost resulted in nickel hydride batteries. These had about three times the capacity of comparable lead-acid batteries. This was still less than needed. It did, however, enable a new generation of electric vehicles. Hybrid and otherwise.

Toyota’s ‘Earth Charter’

In 1992 Toyota outlined its ‘Earth Charter’. Its intention was to develop and market vehicles with minimal emissions. Also that year, the USA sought low emission cars. The aim was fuel usage under 3.0 litres/100 km. Three prototypes (all hybrids) resulted. For likely political reasons, Toyota was formally excluded.

That decision back-fired. It prompted Toyota to create the Prius. That car initially went on sale, in Japan, in December 1997.

The original (1997) model NHW10 Toyota Prius. This initial model was sold only in Japan. Some, however, were imported privately into many countries. Pic: Original source unknown.

The initial version’s petrol engine produced 43 kW. Its electric motor produced 29.4 kW. It was powered by nickel-metal hydride batteries. Torque (at zero rpm) was 305 Nm. Later models had a larger petrol engine. It produced 53 kW and 115 Nm torque.

The car was an instant success. Some buyers waited six months for delivery. The Toyota Prius was launched in Australia in 2001.

European hybrids

In 1997, Audi mass-produced a hybrid. It was powered by a 67 kW 1.9-litre turbo-diesel engine. It also had a 21.6 kW electric motor. This was powered by a lead-acid gel battery. The car, however, failed to attract buyers.

Audi's experience caused Europe to concentrate on reducing diesel emissions. Doing so, however, had 'limitations'. Because their emissions fell far short of EU requirements, some makers illegally disguised the true levels.

Meanwhile, most electric and hybrid development was in the USA and Asia. Progress in Europe was initially slow. Now, however, (2020) there are many European electric and hybrids.

Owned by BMW, the first Mini hybrid had a 1.5-litre three-cylinder petrol turbo engine. Its electric motor had 65 kW of power and 165Nm of torque. It was powered by a 7.6kWh lithium battery. BMW claims it can travel to 40 km (about 25 miles) on electric power. A later version has a claimed 47 km (29.3 miles) range. Fuel economy is claimed to be 2.1 litres/100km. CO2 emissions are claimed to be 49 g/km.

Mini hybrid –the Countryman S E ALL4. Pic: https://www.mini.co.uk 

BMW’s own hybrid initially used a 0.65 litre petrol engine to charge the drive battery (if needed). The car has since been replaced by an all-electric version. The 42.2 kWh battery enables a claimed range of 310 km (194 miles).

Porsche has two hybrids. The 2019 Cayenne E-Hybrid has a 3-litre turbocharged petrol engine. It is claimed to produce 250 kW and 450 Nm torque. An electric motor adds an additional 100 kW. Plus 400 Nm torque.

The Porsche Panamera 4 (hybrid) is much as the Cayenne hybrid. Its Turbo S E-Hybrid has a twin-turbo 4.0-litre V8 petrol engine. It develops over 505 kW and 850 Nm. Its claimed all-electric range is 22.5 km (14 miles). Furthermore, it is claimed to use 4.9-litre of petrol per 100 km (62 miles).

Volvo's aim is to have either 'mild' hybrids, plug-in hybrids or battery electric cars by 2021. It plans to sell one million hybrids. Its V40 model will have a choice of engines, plus a rear axle-mounted electric motor.

Hybrid off-road vehicles

Hybrid drive works well off-road. The electric motor increases power. The fossil-fuelled motor extends range. Few however, meet 2020 Euro 7 emissions requirements. Fortunately, many have ample space for batteries. This eases their possibly legally required future conversion.

One example is the Lexus RX 450h. It retains its 3.5-litre V6, but has three electric motors energised by a 123 kW battery. This only marginally increases power (i.e. from 221 kW to 230 kW). It does, however, reduce fuel consumption. That claimed is from 9.6 litres/100 km (62 miles), to a commendable 5.7 litres/100 km.

Lexus 450h. Pic: Toyota

The Mitsubishi Outlander LS and Exceed have a two-litre petrol engine and twin electric motors. They can travel up to 55 km on their lithium batteries. Their claimed fuel usage is 1.7 litres per 100 km (62 miles).

Mitsubishi (2019 Outlander hybrid. Pic: MitsubisiNissan’s 

The Nissan Pathfinder Hybrid is available in 2WD or 4WD. Each has a 2.5-litre cylinder supercharged petrol engine of 201 kW and 330 Nm. Its 12.3 kW electric motor is powered by lithium batteries. These are charged by the engine’s alternator, and regenerative braking. Fuel use is a claimed 8.6 litres per 100 km. The battery packs are under the forward-most part of the boot floor.

Subaru’s XV Hybrid uses a 2.0-litre, flat-four direct-injection petrol engine producing 110 kW of power (down from 115kW in the rest of the range) at 6000rpm and 196Nm of torque at 4000rpm. It has a lithium battery and electric motor to assist the petrol engine. It can be driven as electric only, electric motor assist or petrol engine only driving modes.

The Range Rover hybrid has all-new light alloy monocoque construction. It is unusual in being diesel-electric. The 2020 PHEV P400e's combined power is 297 kW. The maker claims a range of up to 48 km (30 miles) in electric mode. Regenerative braking assists charging.

The Range Rover Evoque hybrid. Pic: landrover.com

The Land Rover is (now) much the same vehicle. It is, however, marketed as a more serious 4WD. It is, however, not necessarily cheaper. A few models (e.g. the LR4 HSE LUX) are more costly than Range Rovers.

Hybrid vehicles and emissions

When comparing emissions, fossil-fuelled power station efficiency needs taking into account. Most convert about 38% of their fuel into usable energy. Petrol burned by cars converts only 25%.

Energy is also lost in producing petrol and diesel. It is also lost in conveying electricity from power station to electric outlets. Furthermore, in charging electric (and hybrid) car batteries.

The National Transport Commission report assesses CO2 emissions intensity of passenger cars and light commercial vehicles in Australia. The data shows average CO2 emissions of all new cars sold in Australia during 2019 was 180.5 g/km. This is far higher than for new passenger vehicles in Europe. There, (using provisional European data) it was 120.4 g/km. Moreover, corresponding figures in Japan and the USA were 114.6 g/km and 145.8 g/km, respectively, in 2017. As that if latest available data, such emissions are almost certainly now even lower.

The National Transport Commission report reveals that Australia’s result is largely due to the increased popularity of dual cab utes and SUVs. These are three largest CO2 contributing vehicle segments. Furthermore, there are also few Australian government incentives for lower emissions vehicles. Moreover, Australia's fuel prices are low compared with Europe.

In 2019 Suzuki is reported as having the lowest average emissions intensity (128 g/km). Ford is reported as having the highest (210 g/km). A Prius Hybrid emits 107 gram of CO2 per km.

Emissions: petrol versus diesel

On average, the CO2 emissions of diesel cars (127.0 g CO2/km) are now very close to those of petrol cars (127.6 g CO2/km). Moreover, that difference, of only 0.6 g CO2/km, was the lowest observed since the beginning of the monitoring. Diesel emissions, however, are more harmful. Furthermore, they are all-but impossible to reduce much further.

The majority of new SUVs registered are powered by petrol. Their average emissions are 134 g CO2/km. This is around 13 g per CO2/km higher than the average emissions of new petrol non-SUV passenger cars.

See also Electric Vehicles – Thermodynamic Efficiency & Emissions.

Solar-powered electric vehicles

If adequate solar energy is available an all-electric car is virtually non-polluting. There is a minor emission of rubber particles from the tyres. However, there is no equivalent of 'tailpipe' emissions.

Battery making, however, is seriously polluting. It is common to hybrid and all-electric cars – excepting that the latter have larger capacity batteries. See also Solar Charging Your Electric Car at Home.

An initially promising all-terrain electric car (the Tomcat) was designed and built in Australia in 2012. The first 100 sold out almost immediately. High manufacturing costs (and investor concerns) resulted in the company entering voluntary administration in February 2018.

The all-terrain electric Tomcat – sadly no more. Pic: Tomcat   

The Electric Vehicle Series

This is a part of a series of articles about the history and technology involved in electric vehicles.

1. Why the Move to Electric Vehicles

2. Electric Vehicle History

3. Electric Vehicle - Energy Use

4. Electric Vehicle Hybrids

5. Electric Vehicle - Thermodynamic Efficiency

6. Electric Vehicle Batteries

7. Electric Vehicle Charging

8. Electric Vehicle Charging via Solar

9. Electric Vehicle Motors

Fuel cells for homes and properties

Updated 2020

Fuel cells for homes and properties

Fuel cells for homes and properties provide clean silent electricity. High current prices hinder their acceptance, but this may soon change. Fuel cells enhance solar. Furthermore, they may all but eliminate our need for battery storage. Fuel cells hugely reduce harmful emissions.

Fuel cells for homes and properties provide clean quiet electricity. This article explains how, why and when they will be used. Fuel cells for homes and properties may all but eliminate battery storage. Moreover, fuel cells slash harmful emissions. This is a major bonus for all-electric cars.

The Panasonic fuel cell in the German Vitovalor product. Pic: Viessmann.

In 1839 Sir William Grove invented the first fuel cell. Petroleum was then found in abundance, resulting in fuel cells being overlooked. NASA later revived them.

Fuel cells for homes and properties - how fuel cells work

Fuel cells generate electricity. They do so via hydrogen reacting with oxygen. Heat, electricity and ultra-clean water-vapour results. Fuel cell chemistry is complex, but having no moving parts is a bonus. Fuel cells are easy to use, ultra-reliable and silent.

Hydrogen that fuel cells does not exist in free form. It can be produced from water, biomass, minerals and fossil fuels. Furthermore, it is readily produced from solar energy. Moreover, hydrogen is an energy multiplier and carrier. So, rather than using batteries, hydrogen can alternatively store energy. This is already being exploited (see below).

Fuel cells for homes and properties - hydrogen (how safe)

All fuels store energy. They have to be volatile. But unlike most fuels, hydrogen is not toxic. Furthermore, spilled hydrogen quickly evaporates. It leaves only tiny amounts of ultra-pure water.

Some quote the Hindenburg disaster. This airship used a huge volume of hydrogen contained within the airship's outer skin. That skin was cellulose nitrate plus aluminium flakes. Rocket fuel uses the same products. That of the Hindenburg's finally ignited.

Commercial hydrogen is stored in strong tanks. These are tested and certified accordingly. The risk is no higher than if containing any other fuel. read more...

Convert to your own all solar home

Updated 2020

Convert to your own all solar home

This vital easy to read guide shows you how to convert to your own all solar home at minimal cost. You can readily do this between 50-degree latitudes north/south. This easy to read article shows that to to convert to your own all solar home can save you thousands of dollars.

This article shows how to convert to your own all solar home. Do that and you can slash your power bills to virtually zero overnight. Our current home north of Sydney (Australia), when bought in 2000, drew over 35-kilowatt/hours a day. Whilst over twice that typical it did not worry us. We knew how to slash that by 30% or more overnight at zero cost.  How you can do this too is outlined below. It is your first step to having your all solar home. It needs only a tiny, but vital, change in what you and your family do but it can save you thousands of dollars! From there you continue to reduce energy use - and only when that is done do you start thinking of how much solar you need.

Our all-solar home in Church Point, NSW. Pic. solarbooks.com.au

The above is not how professional solar installers work. They may suggest a change to LEDs but otherwise calculate the energy you use, add a bit on top, and advise solar capacity accordingly. It is a quick and easy approach, but you will need a huge amount of solar to avoid paying power bills.

Convert to your own all solar home - wall warts suck!

Wall warts are those little grey or black boxes plugged into your power outlets. They enable you to turn off your lights, radio, TV etc by their remote controls. A typical home has 20 to 40 of them. Each draws only a tiny amount of power but do that day and night. Many draw far more power than whatever they control.

These wall warts typically suck a third or so of total electricity usage! Fixing the issue is simple. Turn off everything at all switch - never by the remote control alone.  read more...

Hydrogen electric vehicles

Updated November 2020

Hydrogen electric vehicles

It is increasingly realised (and accepted) it is impossible to eliminate CO2 emissions from fossil-fuelled engines. Some vehicle makers even used fraud to disguise this. Globally, governments progressively ban fossil-fuelled vehicles. Part fossil-fuel hybrids too will be phased out. Meanwhile, oil costs increasingly rise as supplies diminish. We are already seeing production of hydrogen-electric vehicles. Furthermore, it is increasingly probable our global economy will be hydrogen-based. Doing so needs major changes. We may, however, have little choice.

Hydrogen electric vehicles - not a new concept

The first known internal combustion engine was invented In 1806, by Francois Isaac de Rivaz. It ran on hydrogen and oxygen. In 1863, Étienne Lenoir developed a single cylinder hydrogen and oxygen powered car. Records show that 350-400 sold.

Interest in hydrogen power then waned until 1933 when Norsk Hydro power converted a truck to run on hydrogen from reformed ammonia. It used the existing internal combustion engine. While coal gas is not 100%  hydrogen, vehicles ran on it during WW2.

Norway's Asko goods vehicles run on hydrogen generated by using solar energy to split water. This produces emissions-free hydrogen and oxygen. SINTEF (a major European research organisation) states Norway could have 10,000 heavy hydrogen-powered vehicles by 2030.

Hydrogen can be produced in many ways

Industry uses hydrogen on an industrial scale. Most however, is produced from fossil fuels. This causes substantial CO2 emissions. There are, however, no common international standards re producing and transporting hydrogen. Nor for tracing its environmental impacts.

Currently, heat and chemical reactions release hydrogen from organic materials. These include fossil fuels and biomass. An environmentally better alternative is via passing electric current through water. This splits water into hydrogen and oxygen. This technology is called 'electrolysis'. It is already well developed and now feasible using seawater via solar or wind generated energy.

Another way ('photolytic') uses energy from daylight. This too splits water into hydrogen and oxygen. It is at  research stage. If feasible, it will produce hydrogen with low environmental impact.

Bacteria and microalgae too can produce hydrogen through biological reactions. They use sunlight or organic matter. These technologies are at an early research stage. They have the potential for sustainable, low-carbon hydrogen production.

Hydrogen is not always 'clean'

Hydrogen is a versatile energy carrier. It's cost, however, depends on how 'clean' it is.

Green Hydrogen has zero carbon emissions. It is produced via zero-emissions sources. Wind and solar powered electrolysis is preferred because splitting water releases no carbon. One 1 kilogram of green hydrogen's energy can produce about 33.3 kWh. In 2020 it costs 3.50 to 5 Euros.

Blue Hydrogen is produced without carbon emissions, or has such emissions captured and stored or reused. Synthetic Blue uses carbon capture and storage and carbon credits etc to achieve net-zero emissions.

Grey, Brown or Black hydrogen is typically produced from natural gas or brown coal. Generating electricity with hydrogen-from-coal will result in roughly the same greenhouse gas emissions as burning coal in a power station.

Global hydrogen energy plans

The USA was the first country to establish hydrogen (and fuel-cell) technology. It was part of its 1970s energy strategy. In 1990, the USA passed the 'Hydrogen Research, Development And Demonstration Act'. This formulated a five-year plan for hydrogen energy research and development. In 2002, its Department of Energy issued the national Hydrogen Energy Development Roadmap. Its guidelines coordinated hydrogen energy development.

In 2012, the US Congress rewrote the hydrogen fuel-cell policy. It increased tax credits for hydrogen refueling properties. It created tax credits for efficient fuel-cells. In 2014, the government promulgated an Energy Strategy. This clarified a leading role of hydrogen in transportation. The National Fuel Cell and Hydrogen Energy Association was formed in 2015.

The USA's hydrogen and fuel-cell research and development was led by the Department of Energy. It was also supplemented by universities and research institutes etc. All were allocated funds.

In 2019, the USA's Department of Energy announced intentions to spend up to US$31 million. This was for low cost hydrogen production, transport, storage and utilisation. It later launched a partnership with fuel-cell makers. All focussed on advancing hydrogen's infrastructure.

Hydrogen electric vehicles - fuel-cells

A fuel-cell is part generator and part battery. It converts a fuel's chemical energy into electricity. The cell is continuously supplied with fuel and air (or oxygen). The output is clean DC. The only emission is ultra-clean water.

Fuel-cells have long been used in space applications. Many are installed in hospitals, schools, hotels, office buildings and countless RVs. They can supply both main and backup power. Some are powered from methane produced by decomposing garbage. Smaller fuel cells are powered by ethanol or methanol.

The first fuel-cell powered vehicles (in 2002) were from Daimler-Benz, Ford, General Motors and Nissan. http://fsec.ucf.edu/en/publications/pdf/fsec-cr-1987-14.pdf.

The USA's take-up of fuel-cell powered cars is slow but steadily growing. In 2020 approximately 10,000 are used in coastal California. The California Fuel Cell Partnership has outlined targets for 1000 hydrogen refueling stations. Also, for about one million fuel-cell electric vehicles by 2030.

Hydrogen electric vehicles - European Union support

The European Union (EU) is pushing a vehicle hydrogen-program for aviation and heavy industry. The EU’s CO2 legislation for passenger vehicles includes SUVs. If fossil-fuelled, the EU requires average fuel consumption of 150 km (92 miles) per U.S. gallon (about 3.8 litres) by 2030. This is a serious engineering challenge. Vehicle makers thus welcome an alternative CO2-free fuel. Hydrogen is by far the favourite.

Producing hydrogen in Europe is not a problem. It can utilise excess capacity from wind-farm. There is ample such capacity in Germany, Denmark, the Netherlands and Scotland. There is ample hydro-electric power in Switzerland. In Germany, hydrogen is currently burned as waste.

The EU regulations virtually require new cars in 2030 to be battery or fuel-cell powered. The (global) Hydrogen Council estimates that by 2050, hydrogen will power over 400 million cars and SUVs. Furthermore, up to 20 million trucks and five million buses. Moreover, it forecasts that hydrogen will, by then, provide 18% of the world’s energy.

David Wenger of Wenger Engineering Gmbh organises seminars on 'fuel-cells being inevitable'. He emphasises that investors are embracing hydrogen. Also, that companies like Toyota and Hyundai lead the way. 'People are starting to wake up to the benefits of hydrogen as industry tries to fulfil obligations from the Paris Agreement on Climate Change. Investors are moving in to help improve the product and lower costs.

Should car buyers go for fuel-cells rather than battery electric?

It is still being argued that producing hydrogen traditionally uses as much carbon dioxide as saved by via the fuel-cell process. Also that the renewable capacity from wind, solar and hydro-electric to provide enough hydrogen competitively doesn’t exist. And even if was, distribution and storage costs would be prohibitive. Far from all agree with that.

A 2020 California Energy Commission, report outlines a plan for developing renewable hydrogen production. It predicts that future hydrogen demand and costs makes this worthwhile. The key findings are: 'the dispensed price of hydrogen is likely to meet an interim target based on fuel economy-adjusted price parity with gasoline of $6.00 to $8.50 per kilogram by 2025.'

    Fuel-cell car and other electric vehicle buying cost

    Apart from lacking an adequate fuelling network, fuel-cell cars are expensive. The few currently for sale cost around US $60,000. That’s almost twice as much as comparable electric or hybrid vehicles. In California, however, fuel-cell powered vehicles attract up to $10,000 tax savings, and a $15,000 fuel card.

    In addition to small volumes (large-scale fuel-cell vehicle production is yet to be industrialised) there’s also a need for the precious metal, platinum, which acts as a catalyst during power generation. The amount of platinum needed for vehicle fuel-cells has already been greatly reduced. 'The general goal is to bring down the price of hydrogen-powered cars to a similar level to that of other electric cars,' explains Rücker.

    One reason why hydrogen fuel-cell cars are costly is their large size: their hydrogen tank(s) take up a lot of space. The motor for a 100% battery-driven electric vehicle, however, fits into small cars. That’s why electric cars are made in all vehicle classes.

    Fuel-cell car and other electric vehicle running cost

    A fuel-cell powered electric vehicle typically travels about 28 miles (45 km) on 1 lb (0.45 kg) of hydrogen. Currently, 1 lb (0.45 kg) of hydrogen costs around 14 $US in the U.S. In Germany, a joint venture (H2 Mobility Partners) will provide nationwide hydrogen refueling stations. The H2 Mobility's agreed price for 0.45 kg is the equivalent of 4.8 $US.

    The cost per mile of running hydrogen cars in the USA is currently almost twice as high as that of battery-powered vehicles charged at home. BMW’s expert Axel Rücker expects these operating costs to converge: 'If the demand for hydrogen increases, the price could drop to around USD 2.50/lb (USD 5.60/kg) by 2030 forecasts Axel Rücker.

    The cost of hydrogen fuel-cell vehicles has to include that of transporting and storing hydrogen. The gas can be in compressed liquid or gaseous form. The trend is towards compressed liquid. Either way, transporting and storing hydrogen is more complex and energy-intensive than for petrol and diesel.

    Hydrogen electric vehicles - driving a fuel-cell powered vehicle

    A  fuel-cell car's propulsion is purely electrical. Driving one is similar to driving an electric car. There is virtually no engine noise. Furthermore, all accelerate well. This is because electric motors provide full torque at low speeds.

    Another fuel-cell car's advantage is quick charging time. Depending on the charging station and battery capacity, fully electric vehicles currently require between 30 minutes and several hours for a full charge. The hydrogen tanks of fuel cell cars are refilled in less than five minutes: much as with refuelling a conventional car.

    For the time being, hydrogen cars have a longer range than purely electric cars. A full hydrogen tank will last around 300 miles (approx. 480 kilometres). Typical plug-in electric cars travel about 160 km (about 100 miles) on a single charge. This range can be extended by having more battery capacity – but that increases vehicle weight and charging times. Fuel-cell vehicles, however travel 480 to 640 km (300 to 400 miles) per fill-up.

    Hydrogen electric vehicles - summary

    Hydrogen fuel cell technology can make ecologically sustainable travelling possible. This necessitates using renewable energy sources for hydrogen production. It also needs doing so in more places to shorten transporting.

    In a recent (mid-2020 report) Bloomberg New Energy Finance, in alluding to the possibilities of a hydrogen economy, noted that it would take a global government subsidy of US$150 billion over 10 years to do so.

    Electric Vehicle Series

    This is a part of a series of articles about the history and technology involved in electric vehicles.

    #1. Why the Move to Electric Vehicles
    #2. Electric Vehicle History
    #3. Electric Vehicle - Energy Use
    #4. Electric Vehicle Hybrids
    #5. Electric Vehicle - Thermodynamic Efficiency
    #6. Electric Vehicle Batteries
    #7. Electric Vehicle Charging
    #8. Electric Vehicle Charging via Solar
    #9. Electric Vehicle Motors
    #10. Electric and Hybrid Vehicles

    Interconnecting batteries in series or parallel- here’s how and why

    Updated 2020

    Interconnecting Batteries

    Interconnecting batteries in series or parallel is totally feasible. But its best to know how it works - and the limitations of each. Collyn Rivers explains.

    Interconnecting batteries in series increases voltage. Current remains as before. Interconnecting batteries in parallel increases current. Voltage remains as before. No matter how connected, the stored energy remains the same.

    A common need for series connection is that most batteries are two, six or twelve volt. Some vehicles, however, have 24 volt systems. These typically have two 12 volt batteries in series. Many stand-alone solar systems use 48 volt storage. These typically have four 12 volt batteries in series.

    At common need for parallel connection is in systems above 100 amp-hour. A typical 12 volt deep-cycle 100 amp hour battery weighs about 32 kg. To ease handling it's common to parallel multiple such batteries. Lithium batteries of similar capcaity are one third the bulk and weight.

    Interconnecting batteries in series or parallel - the pros and cons

    Each way of interconnecting has its pros and cons. But not the same pros and cons. Nevertheless, if one needs over twelve volts, and/or substantial capacity, there's little choice. One must increase voltage or current. Or both.

    batteries series (6-12 volt)

    Series connection

    A minus of series connection is that usage is limited by that of the 'weakest' cell. Series-connected batteries must thus be of identical type, capacity and condition. This is particularly so with LiFePO4 batteries. These also need monitoring to ensure all cells are at equal voltage. read more...

    Grid-connect solar modules for RVs – here’s how you can use them

    Updated 2020

    Grid-Connect Solar Modules

    Using grid- connect solar modules for RVs is readily done but needs an MPPT regulator. This article by Collyn Rivers explains how and why to do it.

    Grid-connect solar modules are often sold very cheaply.  Most however produce optimum power at voltages that cannot be handled by the 12-24 volt solar regulators used in most RVs. Using grid-connect solar modules for RVs is however readily done by using an MPPT (Multiple Power Point Tracking) solar regulator. These accept a much wider voltage range. Grid-connect solar modules for RVs can also be used in stand-alone solar systems. This article by Collyn Rivers (Solar Books) explains how and why.

    Grid-connect modules are made in a huge range of voltages and sizes. Those of around 300-350 watts tend to be the best value for money. Most output about 50 volts at 6-7 amps.

    Grid connect solar modules for RVs - juggling volts and amps

    An MPPT solar regulator 'juggles' incoming volts and amps to produce whatever needed to charge your solar system's batteries deeply, speedily and safely. For RVs such as camper trailers, travel trailers and motorhomes this is usually a (nominal) 12 or 24 volts.

    Care is needed when buying an MPPT solar regulator when using grid-connect solar modules for RVs. Some accept any input voltage from as low as 9.0 volts to often well over 100 volts. But some work only from 9-36 or so volts. Others have an upper limit of about 50 volts. This will be shown in the maker's literature.

    solar regulator morningstarThis 400 watt Morningstar MPPT solar regulator is ideal for smaller systems. It will accept input from solar panels up to a nominal 36 volts. (The maker emphasises its use with grid-connect solar modules for RVs.) Pic: Morningstar.

    MPPT regulator do not need prior setting for incoming solar voltage. They do need setting for the type and voltage of the battery/s used (e.g. lead acid, AGM, gel cell etc), and usually for the capacity (amp hours). This is usually easy to do. If in doubt ask the vendor (or most girls or boys from 9-35).

    Outback Power MX60

    The Australian-designed (now US-made) Outback Power MPPT units will accept up to 110 volts or so at up to 80 amps - ideal for larger systems on motorhomes, converted coaches - and home stand-alone systems. Pic: Outback Power.

    Can I legally install grid-connect solar modules for RVs myself?

    In Australia, it is legal for non-electricians to install grid-connect solar modules etc, as long as the solar array's nominal voltage does not exceed about 60 volts DC. You are unlikely to experience other than a tingle up to 24 volts. Care is still needed, particularly if working on the RV's roof. Anything above 50 volts or so can give quite a shock. Unless experienced in electrical work have someone who is to assist you. If the modules produce or are series-connected to produce above 60 volts dc, you must use a licensed electrician.

    Be aware that many (probably most) ultra-cheap solar regulators are claimed to be MPPT - when they are not. Stay only with known brands.

    Further information

    Full details of all this, plus a great deal more  is included in my books: Caravan & Motorhome ElectricsSolar That Really Works! and (for bigger systems) Solar Success. See also related articles (under Power/Solar) on this website. My other books are the Camper Trailer Book and the all-new Caravan & Motorhome Book. For information about the author please Click on Bio.

    Electric and Hybrid Vehicles

    Electric and Hybrid Vehicles

    As of 2020 it is realised that reducing fossil-fuelled vehicle to a safe level is impossible. Hence the trend to electric and hybrid vehicles.

    Many countries are already banning (or will ban soon) the sale of fossil-fuelled cars. These include France, Canada, Costa Rica, Denmark, Germany, Iceland, the Netherlands, Norway, Portugal, South Korea, Spain, Sweden and the U.K.

    Twelve American states adhere to California's Zero-Emission Vehicle (ZEV) Program. The USA's Trump administration, however, eased the requirement - from the mandated 5% a year – to 1.5% a year. Unless Trump is (improbably) re-elected, this situation is likely to change. Environmental bodies led by California have challenged Trump's backward step.

    Globally, there is move to electric vehicles. Apart from minor rubber tyre particles they are virtually emission free. They are also about 80% efficient. If, however, their electricity is from fossil-fuelled power stations, their emissions are similar to year-2020 petrol fuelled (or hybrid) vehicles.

    Dirty Power Stations

    Electricity vendors promote grid energy as 'clean'. At present, however, that applies only to its usage. It's generation is mostly filthy. As of 2020, 56% of Australia's electricity is from centralised, carbon-intensive coal-fired power stations.These generate about one–third of all Australia's carbon monoxide emissions. About 21% is from gas. Such power station emissions are similar worldwide. The remainder is from wind and solar.

    Fully electrically-powered vehicles are virtually non-polluting. Most are over 80% energy efficient. If, however, the electricity they use is from most current power stations, their emissions are no lower than of a 2020 model petrol or hybrid vehicle. It thus makes little environmental sense to use an electric-only vehicle unless that electricity is wind or solar generated. This already possible in South Australia. It is also totally feasible (for commuting at least) to charge an electric vehicle by using solar energy at your home or place of work.

    Electric and hybrid vehicles - the energy required

    Urban-living Australians drive an average 38-40 kilometres each day. Most electric cars use about 1.0 kW/h to travel about 5 km. An electric vehicle (used as above) thus uses about 8 kWh of electricity/day. Grid electricity, on long-term contracts, costs about 20 cents per kW/h. If so the fuel cost is a mere $1.60 daily. However, as noted above, using grid power results in no overall fall in emissions.

    Unless you can solar generate about 8 kW/h for daily commuting, it is (in 2020) better to use a hybrid. A typical hybrid generates less pollution than an electric-only vehicle run from current power stations. While hybrids are to be progressively be phased out in Australia from 2030, it is probable that the power station issues will have then been resolved.

    Electrical and hybrid vehicles - charging from home solar

    For those with ample home or business solar, it is readily feasible to charge the battery (or fuel cells) from that source. Such charging can even be done overnight by selling daytime solar energy to a grid supplier. You then repurchase it (often at low off-peak rates) at night. Or, to have ample solar energy available where the vehicle is parked during the day. Where ample sun access is available, there is a business opportunity for parking stations to provide vehicle battery charging. read more...

    Have portable solar in your rented home

    Updated 2020

    Have portable solar in your rented home

    You can easily have portable solar in your rented home. Here’s how to do it simply, safely, legally and cheaply using readily bought parts.

    You can easily have portable solar in your rented home. Here's how to do it simply, safely, legally and cheaply using readily bought parts. Doing so requires space that faces the sun for some daylight hours year-round. It works best within 50 degrees latitude north or south. Use high efficiency (plus 20%) solar modules to maximise input. You must not connect the system to any fixed mains wiring. This precludes using existing lighting. Use portable light fittings instead. Also, slash lighting cost by fitting LEDs. You take all that when you leave.

    Have portable solar in your rented home - here's how

    Group electrical units that you use at much the same time. Examples include a home office, child's study or entertainment centre. Depending on individual needs, make-up one or more systems, each accepting solar input. You can do this by using readily available portable inverter/chargers and battery packs. Grouped electrical devices connect to a multiple power board that can switch each socket individually. The solar unit then powers that board. If solar is adequate it can be used to power a second or more system.

    Where and what you can use

    Top solar modules produce about 180-200 watts a square metre. In most cases, your solar input is thus limited to about 500 watts. This will be a probable 1500 - 3000-watt hours/day if north facing. This runs computer systems plus LED lights, and good LED TVs up to 60 cm or so. It will not run air con, nor heating/cooking appliances.

    All that's needed is stocked by solar equipment suppliers. The parts needed are used also in travel trailers and motorhomes. They readily interconnect. As pictured above, inverter-chargers combine all required apart from the battery. They are often buyable secondhand at bargain prices.

    My books Solar That Really Works! and Solar Success provides ample background for people considering this.

     

     

     

    How to stop paying for electricity

    Updated 2020

    How to stop paying for electricity

    How to stop paying for electricity is easy. This article shows how. Going almost totally off-grid is more affordable than ever. Now the electricity provider pays us. You can do the same - here's how.

    Solar is now cheap

    We always wanted to stop paying for electricity, and now we virtually have. It is getting easier to free yourself from dependence on the grid.

    Many governments subsidise home solar. Most buyers, however, purchase only small systems: typically 1.5 or 2.4 kW (kilowatts). These, in Australia in early 2019 cost A$2500 -A$3000 installed. This helps reduce existing bills, but increasing solar capacity is truly worth considering.

    Our (NSW government) subsidised 6 kW system cost us A$4350. It produces an average of 25-40 kilowatt hours a day. We initially paid the electricity supplier A$ 0.27 per kW/h for about three hours each night. We sold the daytime surplus (of an averaged 17 kWh/day) for a contracted 20 cents per kilowatt-hour for two years. This brought in about A$1200 a year. The initial cost of installation was A$4500. The result was then free power plus an increasing yearly income inside four years.

    How to stop paying for electricity - adding battery backup to our solar array

    As with many others, we prefer not to totally rely on grid-power - even as a back-up. Having self-built our own 3.8 kW stand-alone system in Australia's Kimberley, we knew that do this is totally feasible. But unless electricity exceeds about $1 a kilowatt/hour it is currently not a money-saving thing to do. Whilst going totally off-grid still appeals we settled on a compromise that is proving very satisfying.

    We added a 14 kW/h Telsa battery bank that supplies our typical three/four kilowatt/hour early morning and evening energy draw, and copes with periods of overcast sky. As with any large solar array, even that still results in some solar input. The grid-connection has been retained - but mainly for selling our still considerable surplus. The grid acts now mainly as a 'belts and braces' back-up in the event of solar failure. It is occasionally drawn on to top up the Tesla battery bank - but rarely for more than about five hours a week (in early winter).

    Being virtually non-grid reliant has a 'feel-good' value. It has no price!  See also our article on the following: battery capacity required. 

    Further information 

    Our related book Solar Success explains and illustrates in detail how to a great deal of money when doing all of the above. Tens of thousands of people worldwide have bought it. We promise to return your full purchase price at any time if not totally satisfied. The digital version is downloadable right now by clicking on Solar Success. The print version is stocked by all Jaycar stores in Australia and New Zealand. It is also stocked by many bookshops in both countries - and can be ordered through them if not stocked. The book can also be bought by email (from anywhere in the world) from booktopia.com.au

     

     

     

     

    Connecting travel trailer batteries – there’s no magic way of doing it!

    Updated 2020

    Connecting Travel Trailer Batteries

    Connecting travel trailer batteries is often misunderstood. This article explains what's possible, and why and how to do it successfully.

    A typical travel trailer has an ongoing need for energy. And an occasional need for (high) power. Knowing the difference between energy and power truly assists.

    Energy is the ability to perform work. It was originally estimated that a brewery horse could typically lift 33,000 pounds one foot in one minute. That amount of energy was thus called one horsepower.  This now mostly expressed in watts. (About 750 watts is one horsepower).

    Power is the rate at which energy is used to perform work. If that 750 watts is drawn for one hour, it's expressed as 750 watt hours.

    That brewery horse's one-minute lifting is equalled, in a few hours, by a child.  Horse and child exert equal energy. But the horse needs far more power.

    Battery usage is similar. A starter battery is thus horse-like. It can exert high power. Starting a car engine however takes only two/three seconds. The energy expended is tiny. It's about that used by a 12 watt LED in ten minutes.

    A deep cycle battery, contrarily, is akin to a marathon runner. Less 'power' but energy can be expended far longer.

    Connecting travel trailer batteries - ensuring enough energy and power

    As explained above - most RV batteries have two main (but different) requirements.

    1. Enough power to cope with high peak loads.

    2. Enough energy to cope whilst away from 230 volts etc.

    This can be addressed in two main (but different) ways.

    Different batteries - different characteristics

    Increasing battery capacity increases available power. And, virtually by definition, more energy. There are, however, downsides. You must, for example, have the ability to recharge them. That charging must be both deep and fast.

    Lead acid deep cycle batteries are heavy. Twelve volt versions weigh about 25 kg/100 amp hour. Their life is greatly reduced by frequent deep discharging.Their plus side is (relatively) low price. Plus ready availability.

    AGM batteries are a compromise. They are physically rugged - thus suited to off-road use. AGMs can supply higher power than conventional batteries. They maintain charge far longer (12 months plus in cool climates). AGMs, however, are even heavier than conventional batteries. Discharge needs limiting to about 50%. If exceeded, their life is thereby curtailed. And they cost a lot more. (Gel cell batteries are similar - but less often used.)

    Any 12 volt LiFePO4 battery above 18 amp hour supplies RVs peak power with ease. The energy capacity needed, however. is slightly less. This is because they can be routinely discharged to 10%-20% remaining. Another benefit is that (in RV use) they rarely drop below about 12.9 volts. They are about 35% of the weight and bulk. On the downside they cost far more. They must also have effective individual cell management. Buy only from vendors who truly understand them. These are, however, rare.

    In practice, a 300 plus amp hour AGM will provide the peak power required for any RV. It also has ample energy capacity. AGM batteries are thus a good choice if space and weight permits

    Connecting travel trailer batteries 

    To ease handling, (or obtain higher voltage, or higher current) batteries can be connected together. There are two main ways of doing so.

    Series: consecutively positive to negative. Total battery voltage is the sum of each individual battery voltage. Total current is that of the battery that produces the least current. For example, were all batteries 100 amp hour, but one 50 amp hour, the total output would be 50 amp hour.

    Parallel: positive to positive, and negative to negative.

    Here, all batteries must be the same voltage, but can be of widely different capacity. The available current and capacity is the sum of each individual's current and capacity.

    When connecting travel trailer batteries in parallel, it is, for example, just fine to parallel a 12 volt 10 amp hour battery across a 12 volt 500 amp hour battery bank. The result is a 12 volt 510 amp hour battery bank.

    Battery shed coconut well reduced jpg

    This battery bank (at the author’s previous all-solar powered property outside Broome, WA) had 16 batteries, each 12 volts and 235 amp hour. Each level has four such batteries in series. All four rows are parallel connected.The output is thus 48 volts and 950 amp hour. That's 45,120 watt hours (45.12 kW/h).  Pic: solarbooks.com.au

    Parallel connecting batteries is safe

    Contrary to common belief, this is safe. Like good socialists each (battery) will thus take according to its need, and supply according to its capacity. See Interconnecting batteries in series or parallel re advised limits.

    To increase both voltage and current, you parallel identical strings of series connected batteries. Here, the voltage is that of any one string. The amp hour capacity is the sum of all the batteries' capacity. Doing so, furthermore, is routine in large solar systems. They are typically 48 volts upwards.
    Connecting batteries in series (end-to-end) thus increases total voltage. Connecting batteries in parallel increases total current.
    In every case their total energy (i.e. watt hours) is the sum of each battery's energy so connected.
    There is no magic way of increasing it. 

    Connecting travel trailer batteries - 6 volts or 12 volts?

    Most travel trailers and motorhomes have 12 volt systems. As batteries are heavy, some owners prefer 6 volt batteries. To obtain 12 volts they are series-connected (positive to negative) as below. This results in the same current (as each 6-volt battery) but twice the voltage.

    batteries series (6-12 volt) web
    Series connection. If each 6 volt battery is 100 amp hour (600 watt hour) two series-connected such batteries hold 100 amp hour at 12 volts (1200 watt hour). Pic: solarbooks.com.au

    If more capacity is required, further pairs of so-connected batteries are then wired in parallel as shown below.batteries series-parallel

    Here, four 6 volt 100 amp hour batteries can hold 200 amp hour at 12 volts (2400 watt hours). Similar connection (but using 12 volt batteries) are used to obtain 24 volts in converted coaches with 24 volt alternators.                                                                   Pic: solarbooks.com.au

    A few travel trailers have only one 12 volt battery. Most, however, have two 12 volt, 100 amp hour batteries. The result is 200 amp hours (2400 watt hours.)

    If four batteries, each of 100 amp hour are parallel connected, total capacity is thus 400 amp hours (4800 watt hours).  batteries parallel 12 volts web

    Ttypical battery bank for a largish RV. Four 12 volt 100 amp hour batteries store 400 amp hour at 12 volts (4800 watt hours). Pic: solarbooks.com.au

    Probable requirements

    For most RVs, the highest (domestic) power need is likely to be a microwave oven. They draw about 130 amps for 5-15 minutes, typically via an inverter.

    Any LiFePO4 battery used as the main RV supply will cope with ease. Such power can just be met by a 12 volt 200 amp hour AGM battery. But 300 plus amp hour is preferable. Some owners attempt this with 200 or so amp hour deep cycle lead acid batteries. They will supply such power for a short time, but doing so repeatedly shortens their life.

    Connecting travel trailer batteries  - Summary

    The best way to increase available power for the same energy capacity is via batteries capable of doing so.

    Conventional lead acid deep cycle batteries are the least so-capable. AGMs are better. If bulk and weight  does not handicap, a 300-400 amp hour AGM bank readily provides RV power typically needed.

    The highest power (by far) is from lithium-ion (LiFePo4). Any such battery will have ample power to drive whatever you wish. They also have more available energy capacity.They are however costly. Furthermore, they need specialised installation and charging.

    Connecting travel trailer batteries  - further information

    Batteries and their charging are complex subjects. Caravan & Motorhome Electrics explains battery charging in depth.

    If you liked this article you will like my books. They are technically accurate - yet in plain English. Other books are the Caravan & Motorhome Book, the Camper Trailer BookSolar That Really Works (for RVs), and Solar Success (for homes and properties).

    Solar regulators with current shunts – how to fix misleading readings

    Updated 2020

    Solar Regulators with Current Shunts

    If connected incorrectly, solar regulators with current shunts may register twice the true solar input.  Here's why - and how to fix it.

    An RV magazine article once described a solution to a non-existent problem. That Australia's sun can produce excess output that overheats solar regulators. It quoted a Plasmatronics PL 20 amp regulator as indicating 36 amps. And that from an 18 amp solar array. The article advised adding a cooling fan, That, it claimed, enabled the regulator to cope.

    In reality the system's was producing 16-18 amps. That current, however, was being registered twice. Once as it flows through the PL 20 regulator. And again as it flows through the associated current shunt. Forum members sometimes post similar examples. And equally mistaken 'solutions'.

    Ocasionally, your solar modules may briefly produce over their normal voltage. Their output current, is however, automatically limited. Your modules are thus not damaged by excess current. Your solar regulator likewise blocks excess current flow. There is thus no risk of overvoltage battery charging.

    A cooling fan has merit in tropical areas. It may be advisable if air flow over the solar regulator is not feasible. A fan is otherwise not needed. Nor will a fan assist to increase your output.

    Solar regulators with current shunts - return battery connection

    When installing solar regulators with inbuilt monitoring, you must have the battery return path go directly to that battery. Furthermore, if a current shunt is used, it must by-pass that shunt. Moreover, details vary between solar regulators.

    It is not feasible to show how do this in article form. Full details however are in Solar That Really Works! (for cabins and RVs). They are in Solar Success (for home and property systems). The issue is also covered in Caravan & Motorhome Electrics.

    Our other books are the Caravan & Motorhome Book, the Camper Trailer Book. All are updated at least every second year. For information about the engineer/technical author please Click on Bio. 

    Inverters for Homes and Properties

    Updated 2020

    Inverters for Homes and Properties

    How to choose inverters for homes and properties. Inverters convert the solar battery output into 110 or 230-volt alternating current. It is all-but-essential to use one. Using only 12-48 volts is too limiting for all but basic cabins.

    Two Outback Power inverters are interconnected. Pic: Outback Power

    User only inverters marketed as sine-wave (not modified sine wave etc). High-quality sine-wave inverters produce electricity that is 'cleaner' than the average grid supply. Other types do not. They may wreck sensitive electronics. There are two main types of sine-wave inverter:

    Transformer-based inverters

    Those transformer-based are bulky and heavy. This is rarely an issue for homes and properties. Their major plus is inherent overload capacity. Tools and domestic appliances draw two/three times they're running current whilst starting. Transformer units handle this with ease. Some produce twice or more their output rating for 30 minutes or so.

    Transformer-based inverters up to 1500 watts will run from 12 volts. Those for up to 3000 watts require a 24-volt inverter. Anything over that needs 48 volts.

    Only a few (e.g. Outback Power units) can be parallel-connected to increase output. This ability is uncommon. If you need, obtain written assurance of feasibility.

    Switch-mode inverters

    Switch-mode inverters are smaller and lighter. Few, however, have overload capacity. Most only sustain their rated output for a few seconds. The better quality units sustain 80% (of rated output) for constant use. Some, however, may only sustain 50%. Switch-mode inverters work best for loads that draw no excess starting energy. These are rare. Air-compressors  draw many times they're running current whilst starting.

    In Solar Books opinion, the best inverters for home and properties are those transformer-based.

    Inverters involve complex technology. Our book, Solar Success explains inverters for homes and properties. Solar That Really Works! does likewise for boats, cabins and RVs. The top-selling Caravan & Motorhome Electrics covers inverters in detail. All our books are in digital or print versions. Digital ones can be bought right now. Click on a title (above). Print versions are stocked by all Jaycar stores in Australia and New Zealand and most Australian book shops. They are also available via email (and post) from booktopia.com.au

    Grid connect solar problems – what vendors may not reveal

    Updated 2020

    Grid connect solar problems

    Grid connect solar problems include, false promotion and vendor claims, incompetent installation etc. Here's what vendors may not tell you.

    Q. Must solar panels be at an exact angle?

    A local installer says my existing 1.5 kW system's modules must be at exactly the same angle as my latitude. They are only a few degrees out). He say he can fix them for $1000 - so most days they’ll produce a lot more. Is this a scam?

    A. Yes. He’s after your money!. In most areas plus/minus 5º makes less than 1% or so change. It may, however, result in a bit more in summer than winter - or vice versa. Less than that will make next to no change. It is, however, desirable to have them face more or less into the sun around midday. But, here again a few degrees does not matter.

    Q Grid connect solar problems - do I need after-sales service?

    My installer seeks $250 a year for ‘servicing and tuning’ my 1.5 kW grid connect system. Do I really need that?

    A. This too is a scam. Installed solar needs no servicing, let alone ‘tuning’. Unless the modules are truly dirty, there is likewise no need to clean them. Occasional rain does the job. Our own grid connect systems (north of Sydney) remains unwashed since 2010. There is no measurable loss.

    Q. Grid connect solar problems - do I need a tracking system?

    I live in the south of Australia where the sun is much ‘lower in the sky’ in winter. My installer advise using a $5000 (plus $1000 installation) tracking system for my proposed 1.5 kW grid-connect system. He claims it will save the amount of solar capacity otherwise needed by about 30%. Is this true?

    A. What he claims is true. But what he has not revealed is a lot!

    Tracking systems are costly and need ongoing servicing. It is hugely cheaper to accept that loss. You can add another 450 watts more solar capacity for a probable $1250! And zero maintenance.  Find another installer.

    Q. Grid connect solar problems - how do I work out the grid-connect size I need?

    I’d like to install enough grid-connect solar to halve my existing power bill. Installers say they need to calculate how much electricity is used and quote accordingly. Is there any way I can tell if they are selling me more than I need.

    A. This is routine practice. The best way to start, however, is to reduce existing usage. We slashed the previous owner’s 31 kWh a day to 4.1 kWh a day summer and 6 kWh in winter.

    It costs some money up front, however, savings are huge over time. That alone will fix that ‘halving’ you seek. Adding solar then - and only then, will drop it yet further. It is not feasible to explain how in an article. The first third of my book Solar Success shows exactly how to do it. It includes actual examples (including our own). Unless you do this, the installer will scale the system to existing usage. read more...

    RV Solar and Alternator Charging

    Updated 2020

    RV Solar and Alternator Charging

    You can make RV solar and alternator charging work. It is complex on post-2014 vehicles. This ongoingly updated article explains how.

    A sunset - background picture.

    How RV solar and alternator charging works

    A caravan or motorhome battery charges by connecting it across it a source that has a voltage that is higher than that battery has at the time. That battery neither knows nor cares whether that charge is from one source or several. Those sources must all be of closely similar voltage. Ideally, they are identical. If not, the battery will draw mostly from that with the highest voltage. Charging becomes complicated, however, once the battery/s approach full charge.

    What happens then is that the controllers associated with each charging source mistake each other’s voltage for the battery. This may cause damaging overcharging. This is particularly so with AGM and LiFePO4 batteries. This applies also to simultaneous solar and generator charging. Do not attempt to do this yourself unless you know how. This explained in our book Caravan & Motorhome Electrics.

    Suitable controllers for RV solar and alternator charging.

    Most controllers sold for both solar and alternator charging, monitor both solar and alternator input but do not combine them. They switch to whichever has the higher input at the time. Solar Books recommends RV solar users to do likewise. This is particularly so with most vehicles made since 2010 or so and virtually all since 2014.

    Issues with post-2014 RV solar and alternator charging

    Prior to 2014 or so, vehicle alternators produced about 14.2 volts for some minutes after engine starting. This dropped to a more or less fixed 13.6 volts thereon. This, by and large, presented no issues for RV battery charging. Such alternators had a high enough voltage to charge a secondary battery in the vehicle to a usable level for leisure or auxiliary use. Ongoing emissions regulations however require minimising power usage. This (in 2014) extended yet further - to vehicle alternators of variable voltage. read more...

    Solar Shadowing – reducing the losses

    Updated 2020

    Solar Shadowing

    Solar shadowing - reducing the losses is like you partially unblocking a water pipe. Partial solar shadowing reduces your losses proportionally. Except in extreme clouding, however, solar modules produce some output. During daylight it's rare for you to have none.

    Pic: solarbay.com.au

    Solar Shadowing - reducing the losses -  bypass diodes partially assist

    Most 12-volt solar modules have 60 cells. Each cell is connected in a string. A totally shadowed cell produces no current. Blocking one affects all.

    Basic modules supply the current of the least producing cell. To limit this, good quality modules have three strings. Each string has 20 cells. Furthermore, each string has a so-called 'diode'. If activated, it carries current from unshaded strings. This assists, but is not a perfect solution. With only one cell shaded, output is slashed one-third. Furthermore, diodes are not reliable. One diode failing will prevent associated strings working.

    A typical bypass diode. Pic: Original source unknown.

    The ideal is a diode across each cell. Doing so, however, is costly. Worse, diodes fail more often than cells. Reliability is reduced.

    Solar Shadowing - reducing the losses - the more effective ways

    In basic systems, the lowest cell output limits your overall output. With multiple modules, shadowing one limits output of all. The loss is confined to the area shaded.

    Power Optimisers

    Power optimisers attach to existing solar modules. They maximise energy. Power optimisers also eliminate power mismatch. They decrease shadowing losses. Such optimisers can be built into solar modules. Or fitted separately. The concept works well.

    Pic: Enphase micro-inverter (power optimiser)

    Solar Shadowing - reducing the losses

    Our books cover shadowing issues in depth. Solar That Really Works! is for cabins and RVs. Solar Success is for homes and properties. Caravan & Motorhome Electrics covers RV solar and general electrics. All are available in digital or print form. Moreover, our books also cover legal issues. Furthermore, you can download our digital versions right now. Click on the books' title (above). Print versions are stocked by all Jaycar stores. You can also buy them (from anywhere) from booktopia.com.au/

    Solar Modules for Homes and Properties

    Updated 2020

    Solar Modules for Homes and Properties

    This article shows how to know power output from solar modules for homes and properties. It shows how to optimise it for winter or summer.

    Top quality solar modules catch 18% to 20% of the solar energy available. This is typically 140 watts-180 watts per square metre in full sun from about 10 am to 2 pm. Input tapers off before and after. Such modules are priced accordingly. Buy only top quality unless you have ample space for those cheaper but less efficient.

    Solar modules for homes and properties - which way to face?

    For maximum daily input, solar modules should face directly into the sun at mid-day: due North or due South. This is not always feasible, but the loss is not appreciable. Even if facing away from the sun at midday, you will still have worthwhile input. If in such situations (and you have room) simply add more solar modules. Their cost now is so low it will not cost much more.

    Solar modules for homes and properties - at what vertical angle?

    Most books and articles advise to tilt them at the same angle as your latitude (e.g about 33 degrees for Sydney, Australia). Errors of 10 or so degrees, however, make little difference in the yearly total. It is possible to increase winter input (at the expense of summer input) by tilting the modules more upright. Likewise, increasing summer input by having them closer to flat. At one time some people had them adjustable - but this is rarely feasible (or safe) if roof-mounted. But here again, if space is available, simply add solar capacity. This may require a larger solar regulator - it cannot 'overload' the existing regulator but it blocks current input in excess of its maximum rating.

    Solar modules - shadowing losses

    Another issue with solar modules for homes and properties is a loss of input when your solar modules are shadowed. Some loss is inevitable. The losses, however, with up-market modules is far less. Attempts to save money by buying cheap solar modules is counter-productive. There are also solar modules that each has a mini-inverter. With these, shadowing losses are reduced.

    Solar modules for homes and properties - solar module types

    There are two main types of solar modules for homes and properties: polycrystalline and monocrystalline. Until recently the latter produced more per square metre and priced accordingly. The best polycrystalline solar modules are now (2020) of similar efficiency and price. This is not an area in which to seek bargains. By and large, you pay dollars per actual watt. Not marketing watts!

    Solar modules - the capacity you need

    The minimum capacity you need varies according to your energy usage, your location and the time of year. See our article How much solar energy -where and when

    Full details of all aspects of this and other related topics are in Solar Success. For solar in travel trailers and motorhomes see Solar That Really Works!