This article explains how to choose the right inverters for cabins and RVs. They convert 12 or 24 volts dc to 110 or 230 volts ac. 

This is a small transformer-based inverter. Pic:Jaycar.

Inverters for cabins and RVs

Care is need when purchasing inverters for cabins and RVs. There are substantial differences in price, but their range and quality reflect much what you pay.

There are two main types of inverter: transformer and switch-mode.

Transformer-type inverters are large and heavy, they can, however, supply several times their rated load. Some can do this for 10-30 minutes. This is a necessary requirement for many electrical devices that have electric motors. These draw two or three times their running current whilst starting. Air pumps and compressors, however, require even more as they start up on their full load. Small transformer-based inverters are still readily available. If weight is not critical they are often a better buy. Most produce twice or more their rated output for a few minutes. Some do so for up to half an hour.

Switch mode inverters are lighter and smaller. Most, however, can only sustain their rated output for a few seconds. That sustained output is typically 80% of that seemingly claimed, however, cheaper ones may struggle to maintain 50%. Because of this, switch-mode inverters for many usages may need to be rated to cope with high start-up loads. A suitable transformer-based inverter may actually be cheaper.

Connecting to inverters for cabins and RVs

Most small inverters have inbuilt socket outlets. You may plug appliances into those sockets (or via a multi-outlet power board). In many countries (like Australia) you must never connect their output to any fixed grid voltage wiring. Doing so bypasses all safety devices such as circuit breakers and RCDs. You may, however, plug in a multi-outlet power board (as that is not legally an ‘appliance). 

Inverters for cabins and RVs (and their installation) is covered in depth in our books, Solar That Really Works! , Solar Success and Caravan & Motorhome Electrics. These books are now available right now in downloadable digital form from our Bookshop. They are available in print form from all Australian bookshops – or by email worldwide from booktopia.com.au