Intro and question about solar / alternator charging

Hello everyone. My name is Kyle and I live in Central Ohio and am in the middle of building out my first off grid Van with the intention to full time for at least 6 months. Its a 1996 Ford e-150 with 68,xxx (2 owner handicap van with high roof). I’m running 400watts of solar, 400ah battery bank with AGM batteries and Im at the point of running the rest of my power supply components and have a few questions and looking for advice from some of you all who have actually done it. My first question is regarding running a battery isolator along with solar. I bought a generic relay that works as the battery isolator (120a) and would like to use it more as a backup supply on gloomy days when driving from point A to B. I’m wondering to make the switch between the solar panels charging the battery, to the alternator charging, do I need a cut off switch (or rather 2) that would switch the solar panels off and the isolator/relay on, or am I okay with having them both hooked up and on at the same time? I’m guessing running both might create some problems with overheating/overcharging, but not sure. I know there are options like a smart isolator, but i’ve still seen people running cut off switches with them. I’ve also seen the DC-DC chargers but think those are more of a benefit to people using lithium and/or smart alternators. I’ve also seen a trick little gadget from Renogy that is an all in one dc-dc charger and Mppt solar controller. I know the Renogy product automatically switches between the alternator and solar, but it comes with a price tag I’d prefer not to pay and if I could essentially do the same functions manually by flipping a switch to turn the solar off and isolator/relay on, I’m fine with doing that.

Second thing I’m debating is hooking up shore power. I plan on stealth camping and boondocking quite a bit, but certainly cant say I would never be in a park or friends house with power hook up. It would be nice to run my 120v a/c power devices, and/or charge my battery bank with shore power but its certainly not necessary for me. How often do any of you who have it, actually use it? The reason its more of a concern for me is because if I do run the shower power, at that point it make sense to set it up to also charge my battery bank. And if I do that I would have to upgrade from a regular inverter to an inverter/charger which is a good bit more expensive. An additional benefit to the inverter/charger over a standard inverter is that the inverter/charger has an A/C terminal block that you can run wiring to multiple A/C receptacles like you would in a house. It still has 2 A/C outlets just like a regular inverter has, and all I will be running off A/C is a laptop, a tv/monitor, my cooler/fridge from time to time and something like a small blender for a few minutes. So to those of you running only an inverter, do the two A/C outlets provide enough power for you? I’m thinking i would just plug a surge protector into the inverter and then my laptop and monitor into that and have space for a blender or something else if needed. Otherwise I would opt out for the more expensive inverter/charger so I can hardwire 2-3 receptacles.

I’m trying to save money where I can and dont want to buy a nicer version of something if I’m capable of creating a small workout for myself.

Thank you for any and all info!!

Greetings & Welcome!

You can just hook up your isolator from your starter battery to your house battery(s), no extra switches necessary, but I highly recommend either a fuse or circuit breaker close to your starter battery, and another close to your house battery(s). It is best to have a fuse or circuit breaker on every positive line, as close to the battery(s) as possible.

I just use an extension cord with a 6 outlet power strip ran through a window or door. Simple, easy, cheap, & effective. Then I have an el cheapo generator with a standard automatic battery charger which can be used either with the generator or with shore power. I highly recommend a cheap generator & battery charger for a backup plan if nothing else. I paid $99 for my generator on sale, and $29 for my battery charger. Just got a 1kw generator for a friend on sale at Harbor Freight for $104. (That probably isn’t big enough to run an A/C though. In my circle of close friends, most of us run energy efficient 12v swamp coolers instead of energy hog A/C’s.)

I’m not a fan of inverter/chargers. Inverters aren’t very efficient, and it’s best to avoid them if at all possible. Car cords/chargers are a much better choice, and tons of things are available in 12v versions these days. If you must run an inverter, it’s best for it be separate from your charging system, and turned off when not in use.

Good Luck & keep us posted!

"Always avoid complicated solutions to solve simple problems." ~ OffGrid

Just be sure that the alternator charging is connected straight to the battery, not through the solar charge controller (only via an isolator and the fuses that Van Dweller suggests). The solar charge controller can stay connected because it will sense the battery voltage and won’t overcharge. It will stay in float mode as long as voltage is above a certain threshold. Once you turn the engine off and battery voltage goes down through use the charge controller will automatically take over to maintain the battery via the solar panels.

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