Once you’ve figured out how many amp hours you’ll use per day, you’ll need to figure what combination of solar, alternator, and “shore” AC charging you’ll have access to. Then you’ll know all you need to…
Calculate how much Battery Capacity you need for your Camper Conversion
- For us the numbers were:
So, until we decide to buy a second solar panel, we’ll need need 100Amp hours of capacity to make it 2 days without alternator charging (since the solar only offsets half of our usage). You should avoid discharging batteries below 50% of their capacity to maximize their life, so we’d need a battery system rated for 200 Amp hours to make it 2 days.
And that’s what we’ve done for now, we bought 2x 6V 220 Amp Hour AGM batteries that we’ll wire in series (turning them into a 12V 220 Amp Hour battery bank). If we add a second panel we can boondock indefinitely. We’ll probably end up doing that pretty soon, but for upcoming trips we’re planning on moving camp pretty often so it’s not a priority.
Why are those (AGM) batteries so expensive!?!? What other options are there?
AGM batteries are “maintenance free” and “non vented”. This means that you’ll never have to add fluid, they can be mounted sideways, and that they can safely be placed in the living compartment of a camper (most shouldn’t be sealed in tight enclosures though, check manf).
Why did we choose AGMs at >2x the cost of perfectly nice lead acid batteries? We liked that we didn’t have to build a sealed compartment in the truck bed w/ exterior venting, we liked that we didn’t have to check fluid levels, but we absolutely needed something that could be lay on it’s side to maximize headroom in our truck camper. So for us the cost was worth it, but if your Camper Conversion has more space to spare than budget you may want to look at lead acids.