I learned a few things at this stage too, surprise surprise. Converters and Inverters are different things (inverters change power down from 110V to 12v, converters convert power up from 12 to 110). Batteries are finicky.
We have a 155W solar panel, and a 12V, 4amp fridge, the kind for truckers and tailgate parties that run off a lighter socket. We’ve got a charge controller that I got with the panel, and then the converter that came with the camper, that also has a shore line. Two deep cycle batteries of dubious condition. Then a generator. And a 2amp battery maintainer. And a standalone converter unit, also for running off a vehicle lighter.
Figuring out how to put it all together involved a great deal of mental anguish, time on the internet learning about electricity (I was all good for Ohm’s Law, but when it came to the PEIR wheel I hit overwhelm), and looking for people who knew more than me that could explain stuff.
I think I hit an electrical turning point this time though. By the end of it, it just all seemed so simple. It just all follows back to what’s hot and what’s ground. For years, that has not seemed simple at all, but it’s not so bad.
So without all the many hours involved in the learning curve and emotions, here’s what I did. The solar panel is wired through its charge controller to the battery. The charge controller is awesome, because it reads out the panel output or the battery charge. The converter is suspect, so that is not wired to the batteries. It’s a glorified extension cord. It’s wired to the battery maintainer, though, so any time the camper is plugged into the genny or shore power, the batteries will be getting a little bit.
I wired a 12V socket to the batteries, and the fridge is plugged into that, but I put a switch in the line so it’s easy to turn off. Usually the trailer will plug into the pigtail so that the truck alternator will charge the camper bank, but I haven’t done that. That means running a wire from the battery to the hitch in the truck, which is not an attractive prospect. Although I intend to do it sometime, haven’t yet.
The solar panel runs the fridge all day when there’s sun, plus. We run the fridge after dark for a while and then turn it off at night. The day’s sun recharges the batteries. If we forget and kill the batteries, the genny has a 12V plug with alligator clips to boost them. We have a 500w converter, too, in theory for plugging “normal outlet” things into that runs on the battery, but in practice, the solar panel isn’t strong enough to, say, charge my computer. At least not while the fridge is on. It charges our cell phones no problem though. That’s wired so that we can take it back and forth into the truck where we customarily use it.
Our solar panel seemed a bit vulnerable so I made a wooden frame for it. The travel-protection coroplast pulls out of the “photo corner” corner holders when it’s time for sun. It also has a holster in the camper where it travels. It slides into one tall cupboard in front of the “kitchen” counter, straight in the door. I love being able to build what I need from the beginning instead of retrofitting something sorta adequate later.
The huge solar panel does less than I thought. Now I know that those little bitty panels on RVs definitely aren’t running the tv and fridge and lights. Maybe they’re charging a toothbrush.
Ahhh. That’s all done then. We’re on the fence about whether to wire lights in at all. Little battery lights are so easy, we have bushels of flashlights and headlamps, and usually use candles at night. If we use the camper in the winter at all, it might be another story.