For our electrical system, we wanted to go without the need to hook up to shore power at all. That meant that we were looking to limit our energy usage as much as possible, and being able to charge the battery while driving (from the alternator) as well as when parked for a few days (solar).
We cobbled together a wiring diagram from a number of sources, as we couldn’t find an exact model of what we were trying to do. Sprinter-source had a couple of examples for auxiliary battery installations, and we ended up following broken granites guide almost exactly (sprinter-source.com). We bought a DieHard marine battery with 100 amp-hours at Sears (tip: check the Sears price online and walk in with a printout, this saved us $50). The battery, ACR (automatic charging relay, Amazon) and maxi fuse block (Amazon) are all installed below the passenger seat, and we used 4-gauge wire from the local auto parts store for all the connections.
So here’s our wiring diagram, and please excuse the 3-year-old handwriting:
As for the solar installation, the conversion source book was invaluable and we ended up purchasing a set from AM Solar in Oregon. We opted for a 135W panel (made by Grape Solar) with the SunCharger 30 charge controller. The panel went up on the roof with 35mm mounting brackets to allow for air flow under the panel (you need at least 1 inch clearance) that are glued, not screwed to the roof using 3M VHB tape – we haven’t had any issues and have driven 10,000 miles with it. To guide the solar cable through the roof, we made a 1/2 inch hole and used a BlueSea cable clam (Amazon) to seal it.
Solar charge controller and fuse block (Amazon) for our appliances are mounted below the drivers seat (facing backwards). It’s a convenient location to monitor the charge current, and changing fuses is equally easy.
Lastly, our appliances:
- Lighting: we bought Ikea LEDs – they’re great. Not expensive, bright, and most importantly, they run on 12V so you can simply connect them to your car battery. We also installed 3 light switches (Amazon) next to the kitchen counter, for the kitchen under-the-cabinet, living area, and bed area lighting.
- Fridge: After much deliberation, we went with a 37qt ARB fridge (Amazon), which is expensive but has amazing reviews – Amazon had a good deal on it when we bought it. The size turned out to be perfect for us. We could probably do with a smaller fridge but we never seem to have trouble filling it up. Parkinson’s law definitely applies here. The fridge is incredibly efficient, using up only about 1.5 amps in 90 degree heat.
- Ceiling Fan: We have the 5000 version of the Fantastic Fan (Amazon). It works well, and draws about 3 amps.
- Inverter: We bought a cheap 300W inverter (Amazon) that charges our laptop and cordless drill.
- USB plugs (Amazon) and 12V sockets (Amazon): We have a set of plugs next to our bed and the kitchen counter to charge up our phones and plug in the inverter. It’s a great location. Charging phones takes up almost no power.
A couple of other things we learned:
- Watt = Volt x Amp. This was very helpful in figuring out what battery size we needed, solar panel size, as well as how much power we would end up using. The conversion source book has some more detail on this.
- Always disconnect the system / fuses before any electrical work.
- The car battery serves as the ground / negative on the car battery system. This allows you to only run the “plus” cable for your electrical system.
- Wire cutters are great for crimping heavy gauge cables. You don’t have to buy the specialized tool.
- We had no trouble installing all the electrical system after the furniture was pretty much built. But this may not be true depending on the layout of the van. Running wires behind furniture that’s built in can be a pain.