What do you need?
There are basically three ways to charge your battery:
- DC to DC
Solar: Smaller blocks for smaller spots
We most commonly install 60W solar panels. Almost all motorhomes and caravans have a number of items on the roof already - vents, air conditioner, TV aerial etc. A 60W panel is typically 540mm x 630mm x 30mm, so we can squeeze them in places that would otherwise have to remain blank.
A lot of small panels instead of a few large panels also avoids putting all your solar eggs in one basket, so to speak. It only takes a large bird poo or the shadow of a power line or branch, and you may lose all the output from a panel. Better to lose 60W than perhaps 150W or more.,
Mains: Charging from the grid
A mains charger incorporated into your RV will allow you to charge your battery from the grid when the weather is bad or you've used a large percentage of your available battery power.
Many larger inverters also have a built-in mains charger that can automatically detect if the power coming into the inverter is DC or AC. When the inverter detects DC power (ie; coming from your battery), it will convert that power to AC (240V) for your AC powered appliances. When the inverter detects AC power (ie; coming in from the mains), it will use that power to top up your battery and also to run your 240V appliances directly.
DC to DC: Charging from your alternator
DC to DC charging from your alternator is an excellent way to charge your battery whilst driving and an excellent alternative to carrying a generator.
There are some old-school folks who will tell you that DC to DC charging puts too much load on your alternator and uses more fuel, but I'd suggest you challenge them to provide some facts and figures on this assumption.
Electricity is really just organised lightning.
- George Carlin