Most of my wiring was to be run through cabinetry, so I was lucky enough not to need to run too much before insulation and paneling.
1) 12V DC: Battery, charging, wiring, and devices
2) 120V AC: Powering, wiring, and devices
3) Solar Panels and Generators
12 Volt DC:
This is the standard electrical system in automobiles to power the lights, engine, etc. For my van build, I've added a second 12V system. This allows me to use the camper as much as I want, without ever risking draining the starting battery and stranding us.
Choosing a battery is one of the most difficult decisions I had to make. Lead-acid is cheap but extremely heavy, needs vented, requires maintenance and has a relatively short life span. Sealed lead (AGM) is more expensive, just as heavy, but requires less maintenance and doesn't need vented. They also last a little longer. Lithium is the future; it is far less weight, more versatile, longer lasting, and more powerful.
I had chosen the mid-range AGM battery, but while shopping brands, I was convinced to splurge on Lithium. The single Ohmmu 150AH Lithium battery I landed on has the same useable power as three 100AH AGM batteries and weighs around 30 pounds, while AGM would be well over 150 pounds. The Lithium should also last twice as long, and allows for faster charging and discharging.
For my 'phase 1' charging system, I installed a Renogy DCC50S DC-DC Smart Charger with MPPT. This unit is the interconnect between the engine (and engine battery) and my camper lithium battery. When I start the van, the charger waits approximately 15 seconds for the alternator to recharge the starter battery, and then begins to allow the alternator to charge the camper battery as well. The smart charger adjust voltage and amperage to optimize the charging for the specific type of battery, which helps with charging and battery life span. The unit pulls up to 50 amps from the alternator, but reduces the pull as the battery gets closer to full. With a built in MPPT charger, the unit also has inputs for solar panels, which it uses to charge the camper battery as well. The unit will also use the solar panels to trickle charge the starter battery if the voltage begins to drop due to not being driven. Solar panels will likely be my electrical system phase 2. For now, this smart charger is the only method I have installed to charge my battery. Our intention with the van is to drive it every day we're using it, either to travel, or even simply to hiking trail heads or lakes. With that in mind, the smart charger is ideal. If we were planning to park and live in the van without driving every day, we would need to add another charging system (Either solar or 120v AC). In testing, one afternoon and night of living in the camper uses between 10% and 15% of our battery, which is then completely recharged in under 1 hour of drive time.
Wiring for 12 volt DC gets a little tricky, and I used THIS wire gauge calculator quite a bit. Lower voltage power requires higher amperage to accomplish the same task, as higher amperage draw requires thicker wire! Not something you normally think about in automotive setups, but once you begin to think about charging batteries or power inverters, amperage draw becomes a real concern. I bought a large spool of 14 gauge In-Wall Speaker Wire for the majority of my low voltage devices. This wire is wrapped in a white sheath, providing a very clean look, as well as an extra layer of protection against rubbing through. My main charging power is run through a 4 gauge wire. When the engine is charging at the full 50 amps, this wire gets warm.This isn't necessarily an issue, but it is a sign of wasting power. In hind sight, I wish I has run 2 or 0 gauge wire for this span. My charger and battery are near the back of the van, so no question the distance (around 22 feet of wire) is playing a role in the inefficiency. I did run 0 gauge ground wire to future proof the setup, planning ahead for when I add additional charging systems.
Almost all the devices I've added in the camper are 12 volt DC. Our intention is to be able to live off the battery, without requiring an inverter, generator, or plugging in. With that in mind, there are only two devices I've installed that will currently only work if we plug in; the rooftop AC/Heater, and the Microwave. Everything else runs off the battery including the lights, MaxxAir roof fan, USB ports, and the water pump/heater.
120 Volt AC:
This is standard household power, and I've added a plug to the back bumper so I can use an extension cord and plug the van into a normal power outlet whenever I'd like. By plugging the van in, we can run the rooftop AC/Heater and microwave. The refrigerator I bought, while is extremely efficient running off the battery, will also automatically switch to household power if it senses 120V becoming available. In phase 3 of my elecrical system, I'll be adding an Inverter/Charger, which will also charge my lithium battery whenever I plug the van in to a household outlet.
I opted for 10 gauge wiring for the main power feed. This is overkill, but I had it leftover from a previous project, and don't ever want to have to redo this wiring. I ran 10-3 wire through a water-tight conduit from the back bumper 'power inlet' up to a 20 amp GFCI outlet in the kitchen area. From the protected outlet, the 10-3 wire continues up to the rooftop AC/Heater, while more standard 14 gauge wire continues to the microwave and refrigerator. I had originally considered extra outlets inside and outside the van, but eventually decided that we simply don't plan to use many 120 volt devices.
I did purchase an extremely heavy duty 10 gauge extension cord to always keep in the van. Again, this is most likely overkill, but as I had to buy a cord for the van, I wanted to buy the best I could. The cord powers the AC perfectly.
Solar Panels and Generators:
Phase 2 of the electrical system will be adding solar panels. The Renogy charger I have installed can handle up to 600 watts of solar panels, and my roof has enough square footage to fit about 550 watts. It would be far easier, and a bit less expensive to go down to 450 watts, and I'm leaning that direction. With our lights on full, the refrigerator running, and our fan on max power, we're still using less than half that amount of power. Ignoring the rooftop AC and microwave, 450 watts of solar would power us indefinitely, even considering the inefficiencies of peak times of day or shade. I plan to install 3 HQST brand 150w solar panels, with 10 gauge wiring from the roof down to the Renogy charger.
As far as a generator is concerned, the only purpose would be to run the AC or Microwave, neither of which we are considering a necessity. Our goal is to not need a generator, and we do not plan to carry one with us for most trips. That being said, I have tested a Honda EU2000i generator, and it powered our rooftop AC without issue. On the occasional trip where we know it will not cool off at night, we may bring one along just to be able to run the AC for a bit before bed. If we know we will need to run the AC all night, we will likely choose to stay at a campground with a power outlet. If I were to purchase a generator, I would look for a used Honda EU2000i, or purchase a new Predator 2000.
Pictures to come!