Electricity / by Ray Phung

Electricity was a topic that came up early in the planning phases.  We had a lot of hypothetical discussions of the type of amenities we would like to have and whether we would realistically use them.  Then, we thought about how we would generate power (alternator? solar? shore power?) and how large of a battery bank we would need.  I think visuals help tremendously, so I drew this up:

Clearly, I was meant to be an artist. My original design included an inverter and a hard wired AC system, but I decided to use DC only for its simplicity.  

This is quite a large topic, but I will go over installing solar power, hooking the batteries up to the van's alternator, installing the fan, and other wiring and fusing issues.  

Power Generation

Items needed:

We are not really the type of people to stay in RV parks, so having access to shore power was not important to us; we would spend most of our time boon-docking.  Thus our main power generation would be from the van's alternator and from solar panels.  To store the power, we opted to purchase two deep cycle AGM batteries from West Marine.  AGM batteries are completely seal and require less maintenance than your normal flooded lead acid batteries. (It's important to do battery research!). We hooked these batteries up in parallel with each other using 2 AWG wire, which created a 210 amp-hour 12V battery bank. When sizing our battery bank, I created a handy spreadsheet which calculated our average daily usage.  To do this, make sure you convert your watt usage to aH (aH = Watt/Volts), then multiply this times 12 to get daily use per appliance.  

Two AGM batteries hooked up to the ACR and solar panels

The red wire is coming from the PDC next to the car battery and into the ACR.  The ACR is connected to the AMI/MIDI fuse block and into the house battery.  Black cable is coming from the solar charger to a MAXI block and into the battery.  The thin red wire coming to the other MAXI block is going to the switch/breaker panel. 

To hook the alternator up to house batteries, you need to run a battery wire from the van's power distribution center, which is a set of terminals near the van's battery.  I fused it with a 125 Amp AMI fuse from the PDC and ran a 4 AWG cable (the T1N Sprinter stock has a 90aH alternator). This cable was bundled and routed with the existing wiring harness, and pulled through the rubber gasket below the drivers seat.  From there, I routed it under the driver's side step, under the b-pillar, and through the cabinetry to the electricity cabinet.  From there it meets the ACR.  The ACR combines the house and the van's battery when the van is running, but separates the two when the vehicle is off.  That way, it prevents you from draining your vehicle battery when the engine is off, but allows the alternator to charge the house battery when the engine is running.  The ACR is then connected to the House battery.

Solar panel wiring going into the cable clam and dropped into the van.  It's then connected to the solar controller

Solar panels and fan installed on the roof.  

I purchased a 300 watt solar array from the folks at Renogy solar, which also came with their Adventurer solar controller.  This gathers the energy from the panels and directs it to the battery. Installing the panels was an ordeal.  I wanted to avoid drilling holes in the roof, so I opted to use 3M VHB tape which many companies use to attach panels to RV's.  But due to the curvature of the van's roof, only two of the four solar panel's feet would sit flush with the van; the other two were maybe 40% stuck on.  This is one of many times i discovered that there are no straight lines in the van. I tried several other methods to secure the other feet, such as using Eternabond tape and adhesive/sealant, but eventually I drilled holes in the roof and used pop-rivets to secure the feet down.  I made sure to fill the holes with sealant to prevent water leaking.  

Adventurer solar controller and the 5 gang switch/circuit breaker panel. 

After I secured the panels to the roof, I connected all the wires in parallel.  I used a boring bit to drill a large hole in the roof to drop the wires down into the van.  To seal the hole, I used a BlueSea Cable Clam.  The panel wires were routed inside to the solar controller.  I used a coping saw to cut a hole in the cabinetry to install the controller.  From the controller, 10 gauge battery tray cables were routed down to the batteries.  At this point, all power generation was hooked up to the batteries.

Power Usage

We determined our main power usages to be the following -

All of these items would need to be fused and wired into some sort of distribution panel.  I opted to use a 5 gang rocker switch panel which has circuit breakers built into it.  These are used in boats to distribute power to various DC electronics.  It has fuses built in and has a pretty sleek design. Plus, switches are fun!  It was installed on the surface of the storage cabinets were all the electricity wires were routed to.  This distribution panel was powered from the battery and fused separately with another MAXI fuse.    

Yikes.  Cutting a huge hole with a jigsaw

Fan-tastic Fan, fully installed. 

We chose the Fan-tastic Fan 807350.  It uses very little power, uses a remote, and automatically shuts off in the rain.  To install the fan, I made an outline out of cardboard and traced that shape on the van roof.  I drilled some pilot holes and then used a sheet metal blade on my jigsaw to cut it out.  It was a little terrifying cutting in the roof.  And even more terrifying when the hole wasn't quite big enough, so I had to make the hole bigger by trimming it.  I filed the sharp edge and painted the exposed metal to prevent rust.  I used the supplied screws to secure the fan down, and then applied 3M 4000UV sealant underneath the fan and put Eternabond tape around the fan edges.  The wires were extended and routed to the distribution panel.  Later on, after it started raining, i had to re-seal the edges due to leaks.  Next time, I would use some sort of butyl seal tape to seal it off to prevent this from happening.

The ARB refrigerators are top-opening chests that are popular among the off-roading 4x4 crowd, namely for their durability and their low power consumption.  On our recent trip to bishop, it was left on the entire time and used very little power.  They can be ran off of DC power, which I decided to hard wire into my distribution panel.  The 37 quart seemed big enough for our space and for our needs.

Taking apart the original Dioder controller

New, glass-faced controller wired up and installed.

For lights, we chose to use Ikea Dioder sets.  They come in packs of 4 round or strip LED lights.  We opted for the round ones.  They are pretty bright, and since they are LED, consume very little power.  For the kitchen area, I opted to put regular warm colored lights.  For our sleeping area, I went with the colored LEDs because, well why not! I decided to replace the controller that came with the lights because it looked cheap and tacky. In it's place, I got a glass wall-mounted panel.  I took apart the original controller and unsoldered the connections coming from the lights.  After i figured out which wires were which, I was able to plug these directly into the new controller.  Power and ground went into the V+ and V- slots, and the Red, Green, and Blue wires went in accordingly.  For the kitchen light, I purchased a separate light switch.  That way all lights could be fused together (one main switch), but then two light areas can be turned on or off individually. The colored LED and kitchen lights were wired together and fed into the distribution panel. 

Color Dioder LED lights

White Dioder lights in the kitchen

I thought a water pump would be nice to have so we could just turn a handle and get water.  No hand or foot pumping for us.  Plus the pump was extremely cheap from Amazon, and uses a negligible amount of power.  The pump was easy to mount and easy to wire.  I got these 12V DC plugs from Amazon as well and mounted them to the bed for easy access when we are lounging.  After using our propane stove inside for cooking, we are currently leaning away from using a built in cooktop.  Purchasing a big enough inverter to power a cooktop (most run on 1500 watts +) is expensive and would drain our batteries pretty quick.  Plus, having extra counter space is nice.  

Fusing and wires size diagram.  I used this at West Marine when i was making my own cables.  This also lists the terminal sizes of all the various connections.

Then, all the negative wires are plugged into a bus bar, which is ground to the van's body.  When putting in the panelling behind the cabinets, i made sure to leave at least one 3/8" bolt hole exposed so i can have a good ground.  

Wiring the electricity seemed scary at first, but it wasn't too bad.  Just make sure you have the appropriate wires sizes and fuses (see #4 below and my fusing diagram!) and make sure you disconnect the things that can shock you. 

Lessons Learned:

  1. Nothing in the van is in a straight line
  2. Planning out your electricity scheme is very helpful
  3. For ease of connection, I used crimp-on connections.  Practice using these and crimping on connectors.  It takes some finesse to crimp them securely
  4. Use heat shrink tubing for a clean install
  5. Blue Sea Systems has a great wire-size/fuse-size chart.  I used this a lot.  Bookmark it! http://assets.bluesea.com/files/resources/brochures/980006450.pdf
  6. Many hardware stores and marine stores will sell wire by the foot. This is many times cheaper and reduces waste. 
  7. Get a list of all the stud sizes for the fuse block, ACR, and battery.  They are all different.  It helps to make your own wires, as the pre-cut ones often don't have the right terminal size (see diagram above)

Rear of the solar controller and the distribution panel, showing how all the wiring is routed.