Fitting solar panels to a Caravan or Motorhome

Having to find a mains charging point to plug into to charge your batteries every other day seriously restricts your freedom. Imagine all the beautiful wild places you could stay, if instead of relying on the national grid for your power, you got some or all of your energy from the natural power of the sun or the wind?

To make a significant contribution to the energy needs of a caravan or motorhome you probably need a panel of at least 50 watts power output. In summer, a panel of that size should provide enough electricity for lighting, water pump and a radio. If travelling early or later in the year, when there is less light available, a bigger panel may be necessary. If you are running a fridge or a television, you should consider installing several panels, as they can be very power hungry.

Framed panels such as the UniSolar and BP Solar ranges are the most cost-effective panels for a given output, and can either be left unfixed, and plugged in when necessary, or mounted permanently on the roof.

An alternative, sophisticated solution is to fit a flexible adhesive backed solar panel to the roof. These look great, have an extremely low profile, and are very easy to fit.

If you have to leave your caravan or motorhome for long periods, you might want to fit a small solar panel to keep the battery topped up, as batteries do tend to self-discharge over time, and discharged batteries soon become sulphated and lose their capacity. The Spectra range of panels are ideal for this job, and come in 5, 10 and 20 Watt sizes. They are semi-flexible, and will gently bend to fit to a caravan roof. They can be mounted either using the 4 grommet holes in the panel corners, or by gluing the panels down.

The small Spectra panels do not need a solar controller if the capacity of the battery bank (in Ah), is more than 10x the power rating of the panel (in Watts). For example, a 110Ah battery with a 10 Watt panel would be fine, but for an 80Ah battery with the same panel we would recommend fitting a solar controller such as the MorningStar SunGuard model. For larger panels such as the UniSolar models or most of the BP panels we would always recommend the use of an appropriately rated solar controller.

An alternative to solar panels is to use a wind turbine, such as one of the Rutland models. However, these would need to be taken down whenever you move, so are not the 'fit-and-forget' solution that solar panels offer. For static caravans, or if you are likely to be in one place for a while, they may prove to be a cost effective solution.