A Post by Andy
{Note: The work detailed in this part of the post was completed over the summer of 2015, before we moved into the Turtle. I am just getting to writing the post now.}
So, we like to have our computers run, have lights, have the controls for our fridge work, have a charged Wi-Fi hotspot, and have our furnace fan powered to keep us warm. For all this we need electricity, and since we want to be off-grid, we need batteries. We started with this:
If you are familiar with the Turtle, this compartment is behind the largest access door on the passenger side- the door with the vent in it. In the following photo, I put in a dotted line where the plane of the floor on the inside intersects the compartment.
The walls of the compartment above the floor line are plywood, and bump up under the couch inside. The sides and bottom below the line are made of heavy steel. I have deduced the compartment was originally designed for a generator, as there was old 120V AC wiring running to it, an unconnected fuel line that ran into the back, and the door vent.
I had a hard time figuring out what all the wires were hooked to, as it was a bit haphazard in the compartment. In the above picture, (1) is a port that goes outside, below the floor of the Turtle. The wires there threaded out of the box, ran a short distance under the Turtle’s floor, then threaded up through the floor to the old inverter. There is a second hole (2) that the wires from the old 100W solar panel and the wires between the battery and main 12V distribution panel were run. (3) is the unused electrical box that had 120V AC wires run to the compartment where the shore power cable is housed.
Maybe I should back up a bit and throw out a few concepts and definitions and explanations for the terms we will be using.
- Battery: A thing that stores electricity in chemical bonds. Here, we are just referring to 12V lead-acid batteries.
- 12V/12VDC/DC: 12 Volt Direct Current (DC). This is what cars use for their electricity for headlights, the radio, starting, etc. It is the kind of power all the batteries we talk about will produce.
- 120v: 120V Alternating Current (AC). This is what is in your house and in businesses you know, the typical wall plug Amy and I look for at restaurants to plug our computers into. It’s generally 120, 121, or whatever it takes.
- Current: The flow rate of electricity.
- Voltage: The force pushing the electricity through the wires.
- Inverter: An electrical box that changes 12VDC to 120VAC. It changes car electricity to house-hold electricity. This is so we can plug our AC computer cords into our DC batteries.
- Converter: An electrical box that changes 120VAC to 12VDC. The opposite of the above—pretty much a garage battery charger that you use to get your car started after you leave the lights on.
- Charge Controller: An electrical box that changes the output of the solar panels into DC voltage, hopefully charging the house batteries.
- House Battery: Now, I probably use this too freely. When I talk about house batteries, and I mean batteries dedicated to our living compartment. If I say house (or household) electricity, I mean 120 V AC. Got to figure this out… but, house batteries are 12V batteries separated from the car system, and dedicated to lights and heat and powering the inverter in the house part of a van. One should be able to run these dead flat, and the car will still start, as they are fully independent circuits.
- Starting Battery: The batteries under the hood, used for starting the car, sparking the gas when the engine is running, running a radio (if you had a functional one), and lighting the headlights.
- Shore power: Kind of a boat term, but a source of 120V AC electricity you can plug into. When you pull up at a friend’s house, and pull out your extension cord, and plug into their electricity, they are your “shore power”. (Thanks Alex and Julie, Kari and David, Connie, Mag and John, Dave and Ryanne, Mike and Becky, Blake and Martha, Roger and Mary, Chris, Dad…)
Now, back to the good stuff! To start the battery box rebuilt and modification, I first labeled the wires and removed the old battery. I then cleaned the compartment with baking soda and water to neutralize the sulfuric acid and prevent further corrosion. Lucky, the metal compartment is super stout, so it was still in great shape. As usual, after a final thorough cleaning, I caulked the seams and painted the compartment with black Rustoleum. I can’t find a picture of the completely empty, cleaned and freshly painted compartment, but trust me, it looked good!
After getting the compartment beautified, I cut and painted a plywood plate to fit into the bottom, bolted and glued it to the metal base of the box, and mounted battery trays to it. I painted up everything with oil-based paint and used stainless steel hardware to affix everything.
Since we had just gotten the Interlux blue boat paint, I practiced the painting technique on the top surface of the plywood base, so it is the same shiny blue as the Turtle exterior. In the following photos, you can see the two new Fullriver 115Ah 12V DC sealed AGM batteries that we started with in there, but just patched into the cleaned up existing wiring we are reusing at this point.
I decided to go with Absorbed Glass Matt (AGM) batteries. They cost a bit more than flooded batteries, but they do not spill, they will not develop corrosion at the terminals, and can be mounted sideways, if that configuration seems important. Additionally, they do not require venting, so they can be safely installed inside the living compartment, if that is necessary. Here is the site. We have been happy with this choice, and as you will find out in future posts, choosing AGM sealed batteries will allow us to make some future cold-weather modifications.
As to wiring, I was just starting to adopt the boat convention for new circuits and runs I would rewire. The convention is as follows: For 12VDC, yellow is ground, and red is positive. For 120V AC, the wires are white, black, and green for ground. Examples of the wires are here:
The reason behind adopting this convention is that at a glance, you can tell which circuit they are supposed to be wired to. Additionally, the boat 120V cable is stranded, as opposed to the household solid copper wire. Stranded wires should always be used in a vibration environment. Logically, then, a van should have no solid copper wires (though most RV builders do actually use cheaper solid copper for the 120V runs). As you might have observed, we have concluded that one should think of their van as a boat, and look to boat paints, wires, latches, and hardware for the upgrades and work. Though the boat cable is a little more expensive, it is paired and tinned for corrosion resistance, and gives a real nice finished look. Additionally, it can be purchased in any gauge.
So, at the end of our Phase 1 battery configuration we had our two new AGM batteries with a combined storage of 230Ah at 12V installed and secured, with the connections cleaned up. With this battery pack, we simply used the old converter to charge them when we were connected to shore power, and the old inverter to make our 120V for our computers when off-grid. At this point in our journey I also had just finished the install of our 300W of solar to charge the batteries (we will cover the panels and solar charging and solar controller in a different post).
That’s Phase 1 for you!
The sunset at that spot, later that evening. . . a pretty nice backyard
That time we lived on a lake
Cooke City, Montana. . . The morning we woke up to the roar of a town full of snowmobiles!
Blue Turtle Crossing 