Battery Selection and Installation
Battery Selection
As noted before, I chose to use two 220Ah 6-volt AGM batteries wired in series to get my 12-volts. I think there is already WAY too much written on-line about the pros and cons of 6-volt vs 12-volt batteries and even more written about how many amp-hours are necessary. In the end I chose 220Ah giving me, in theory, 110Ah of usable power (at 50% discharge) which should power my fan, heater, and LED lights for a good long time. The short version for my choices:
- AGM battery because they don’t require venting and are more durable in rough conditions;
- Deep cycle is a given as they are designed for long discharge (as opposed to a starting battery);
- 6-volts are typically a heavier duty build and handle the charge/discharge cycling better; and
- The size and weight of two 6-volts are more manageable than one huge 12-volt.
- I did not go with lithium because of cost and although there were lots of folks doing the long-term cost-benefits analysis, it just didn’t pencil out for me. Nevertheless, please, do your own research on AGM verse lithium because it’s likely the cost of lithium has gone down by the time you read this.
Battery Location
I went around and around on where to put the batteries. My van did not come with any auxiliary battery nor did I want it to. I checked out the options to mount the batteries under the hood, but it started to get complicated and (strangely) expensive – especially since I wanted to mount 2 batteries.
I was almost resigned to building a battery box in the cargo area as part of the conversion when I realized that the two 6-volt AGM batteries I was considering would fit perfectly under the passenger seat. This was a game changer for me. I saw that there was enough room to put a bunch of other control and distribution fixtures in there as well and it had a ready made access holes for routing wiring and for mounting a fuse block. As it turns out there were some significant advantages to this:
- Did not use valuable floor space for installation,
- No long wire run connecting batteries across the engine compartment,
- Shorter wire runs from the batteries to the fuse block and bus bars,
- In turn, shorter runs from batteries to consumers, and
- Batteries would be in the heated cabin increasing output and longevity in cold weather.
I created the battery mount by sizing the batteries in place and marking their location on the floor. I then built an anchor system using high-strength cam straps and angle brackets bolted to the seat base and floor. (The passenger door side angle bracket isn’t visible here.)
I had some 1/4″ thick rubber sheeting that I cut to pad the batteries from the floor and sides of the seat base which I attached using double-sided tape. (Only one rubber piece shown here on the floor.)
Here’s the final setup with the batteries wired in place. I created my own cables with 4ga wire and a crimper and appropriate terminals. Note that in the future I may replace the main battery cables with a bigger gauge (1/0) if I install any higher amperage appliances such as an inverter or induction stove. I also insulated the terminals to isolate them from any accidental contact (not shown). There remained about 1/2″ clearance between the swivel seat base and the top of the battery terminal.
For orientation, the front of the van is to the left. The other stuff you see is covered in another post on Wiring and Fixtures.
To track the power level and charge rate I installed a Renogy battery monitor. The shunt is installed on the forward mounting panel also inside the passenger seat base while the monitor is mounted inside the galley cabinet. I installed it inside the cabinet because the display light comes on every time there was a draw on the battery and at night the display light was annoying. In the end it wasn’t a big issue since I didn’t need to constantly watch the battery and charging level. The only issue I had this unit is that the connector wires at the monitor end became separated from the connector – I suspect they weren’t set properly as there wasn’t a lot of movement or strain on the wires. I tried to purchase a replacement cable, but the response from Renogy was to purchase an entirely new unit! I will obviously have to attempt to fix the connector myself.
