Battery box for a camper van

Tom Cleary
Tom Cleary Solar Expert Posts: 37
Hello:

I'm adding a solar battery system -- this is my first solar rig -- to my camper van and would like your feedback. If you can offer any suggestions on improvements it would be much appreciated.

Is there a fire danger associated with doing the following? My camper van doesn't have a dedicated battery compartment as larger RVs do, and an outside location would be better for venting the batteries by placing the two batteries in a battery box outside. The idea would be to place the charge controller next to the battery bank and route the pv panel wire to the charge controller, then into the battery. Then, after leaving the battery, route the electric wires from the battery back inside the van and use them to power a busbar and an inverter.

The alternative would be to route wires from the solar panel into the camper van to the charge controller, then run the wires from the charge controller back outside the van to a two battery bank, then back inside again to power the busbar and inverter.

Locating the charge controller inside the camper van means adding extra wiring, possibly a few feet in this case. it is important to keep the wiring to the battery as short as possible I've read. Just wondering what others experience has been with this problem?

I've read that plastic battery boxes can burn up. How susceptible is a plastic battery box to dangers of fire? I have heard that marine battery boxes can work well. Has anyone had experience with the double battery box from Todd? Eventually I want to build my own battery box out of wood, but will have enough to do in the near future getting the solar rig working and am looking to buy a double battery box for now. Am trying to learn as much as I can to do this right. Thanks for your help.

Tom Cleary

My proposed system is: Rogue 30 amp controller, Bogart Trimetric 2025, two Costco deep cycle flooded cell batteries, Kyocera 24 volt 185 W panel connected to the cc by a 50 foot 8 AWG (100 foot roundtrip), Morningstar Sure Sine 300 inverter.

Comments

  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Battery box for a camper van

    That's similar to what I'm planning for my camper van. Mine has two battery trays under the hood. One for engine battery, and one for house battery. I don't have any other place to put the batteries outside the cabin, but I have a perfect place under the couch, so I'll be putting two batteries there.

    Since they'll be inside the cabin, I don't want regular FLA (flooded lead acid), with the venting issues, so I'll be using AGMs which are sealed (unless you overcharge them to the point of blowing the seals).

    I'll most likely be going with the Morningstar SunSaver duo charge controller, since it can charge the house battery and also keep the engine battery topped off. It's a PWM charge controller, not MPPT, so it costs quite a bit less than an MPPT controller. PWM is fine though for a single panel setup, since MPPT isn't going to increase my harvest enough to really even notice (probably a single 135w PV flat mounted on the roof), and certainly not enough to justify the extra cost.


    EDIT: Oh, and the way I'm planning to wire it is to run from the batteries (under couch behind driver's seat - I'll make a wooden box to hold them) to the left rear corner where there is already the shore power breaker box (holds two breakers, but only has one 15a in it) and the battery charger. I'll put a "power distribution block" in a metal box:

    http://store.solar-electric.com/16220-1.html

    I'll connect the batteries to the large terminals on the block (big fuse (+) and battery monitor shunt (-) at battery end (also a disconnect switch (+) on the front of the battery box (reachable under driver's seat))), and to the smaller terminals I'll connect the solar charge controller output, the inverter's 12v input, the shore power battery charger output (right now a 10a Shumacher, which I plan to swap out for a bigger Iota), and a 12v fuse block for the 12v loads.

    (Actually, I plan to drill holes for 4 resettable 12v breakers and mount them in the box where the power block is, and then run wires from the block to the breakers, then connect the smaller devices to the breakers.)

    The charge controller will also mount back there as that will keep all the electric together in the back, and I'll put an extra smoke detector just above the collection of electric widgets.

    There is a split-charge relay off the alternator, and I'll probably change out the house battery under the hood for another starting battery and then add a switch so that I can activate the split-charge relay so if need be I can jump start off the 2nd under-hood battery. I'll then run the 2nd battery output from the SunSaver Duo to that battery just to keep it topped off. The battery temp sensor will go to the in-cabin AGMs.

    Down the left side is the driver's seat and the couch behind that, and behind the couch is the cabinet with the fridge. On the rear of that cabinet is where the shore power breaker box is now, so getting down into the van from the PV is nothing, I'll just drop down through the existing fridge vent and then poke through the side of the cabinet to the charge controller.

    To access the electrical stuff, I just open the left rear door and there it is.

    I'll wire the existing shore power breaker box, to the output of a 30a 120v DPDT relay as a poor man's transfer switch (in its own metal box). Incoming on the relay will be the feed from the shore power plug, and the feed from the inverter. When not energized, the relay will default to feeding the breaker box from the inverter, but the coil will be wired to the shore power side, so if there is shore power it will energize and connect the breaker box to the shore power instead.

    I have a portable generator, and I just plug the shore power connection into it when I use it.


    Another EDIT: Oh, and the Iota charger will be wired so it will only work when there is shore power. I'll add another breaker to the existing 2 breaker box (luckily it's a 220 box so I don't have to change it out), and wire it so that that breaker will get power from the shore side of the transfer switch, and then hook up a plug to that breaker for the Iota.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Battery box for a camper van

    Depends to a great extent on the size of the batteries. VW has gotten away with dual batteries in the cabin for years, including the starting battery. One under the drivers seat, the other under the passenger seat.

    Add big FLA batteries and high charge currents and you might have a worry. Plastic boxes can burn up, metal ones can short. Choose your poison. I think I would prefer plastic. Everything else in a RV can burn!

    Tony