My current power setup

I seem to be frequently asked over and over again what I have for power. I’ve been procrastinating this post as I kept adding things, and had more additions in the future. While I still have some planned upgrades I believe the majority of the system is likely to stay this way!

I will update this page as often as I remember. Up to date as of 1/5/2020

Some stats:

1.3kW Solar Array

13kWh Primary Battery

1.2kWh Aux Battery

Notable Equipment:

System Overview

Starting at the van alternator at the top left. Power from this is fed into the Sterling BB124870 a nice DC to DC charger. This takes the 12v “Car electrical power” and converts it to my 48V primary battery bank. It also has a lead hooked up the a set of relays. shown here in green. While the Sterling shouldn’t over charge my battery as a whole, it can overcharge any one cell. We will get to that a bit later. It automatically detects when the car is running and turns on, provided the charge on/off switch from the relay is set to allow charging.

The solar panels are wired 2S2P, which means 2 in Series and 2 in Parallel. Instead of seeing 4* 60v panels at 5.5amps the 2 in Series means they act like 2* 120V panels. Because both of those groups are in parallel the Amps add up. So the solar charger sees 1* 120 volts at 11amps. All that power is fed into a Victron 250/100 MPPT solar charge controller. As with the Sterling this has a charge on/off switch wired to its own relay. This also charges the 48V primary power pack.

Finally we have another Victron charge controller. This is my old solar charger and is only used here because I had it and it does the job well. It is a 150/100 MPPT charger. Instead of solar panels it is hooked into the 48V primary battery bank. The output is connected to my auxiliary battery. Because my inverter is currently 12V, and all of my electronics are currently 12V it actually powers everything.

Fusing, fuses, and wiresize.

My system has a few extra fuses that are not required. The first one is coming in from the solar panels. They are not required because the wire size can handle a full dead short of 11amps. The solar panels cant provide enough power to damage the wiring. They are actually installed because I use them as a switch. If I want to kill solar power going to my controller I yank a fuse. I put in two just to color code my wires and for symmetry.

Another fuse that isn’t required is on the Sterling charger. It does 70A on the 12V side, but that is how much power it pulls. It doesn’t send any power out. It is there because the wire wasn’t long enough and I had two sections. I used the fuse as a splice. It is also handy if I wanted to charge the car battery from one of the charge controllers.

Solar panels

Solar panels that have a length just shy of the roofs width. Just enough room for a paddle board and max fan with them installed this high.

3 of the 4 panels installed.

When I decided to install AC, I knew I would need as much solar power as I could get. These 4 panels cover my entire roof. Not only do they provide shade helping keep the vehicle cook they are rated at just over 1300 Watts. Typical dwellers have panels in the 100-400 Watt range. Even with all this power, I don’t have unlimited power!

I found a really great deal on these panels on Ebay, but they have a store as well. Here is a link if you want the same 327W sunpower solar panels that I got. https://www.santansolar.com/product/sunpower-327w-e20/

I got these used because they fit my budget at the time. I wanted a higher end panels, however the difference between the highest end panels and my panels are maybe 100w for the entire system. That isn’t worth three times the price! I was able to dump my savings into my battery bank!

Battery bank

Every project seems to have many steps and this one was no exception. As you can see I needed help with this one. Grant was thankfully able to capacity test the batteries for me. This allowed for grouping them into the best possible groups for the highest capacity. I used https://secondlifestorage.com/repackr.php and the capacities from what Grant was able to record during his testing.

Shout out to Grant who capacity tested 52 battery cells! Not only that, he did it with a charger he bought for maintaining and testing RC and hover-board batteries. Compared to what he is used to charging mine are massive. Due to how large they are relative to the charger that he had the best he could do was test up to 4 a day. I believe the wait was worth it though.

Analytics

Part of the requirement for my system was to be able to log the data. Previously I threw a system together myself, however recently I’ve been using openhab as well as home automation equipment and technology. Most noteworthy here would be the power systems. It would take too long to dig up historical data and I just recently rebuilt everything with the new solar charge controller so I only have a couple of days worth of solar logging with openhab. I’ll eventually do a complete write up on both the data collected what it teaches us as well as what I’ve used for home automation in a van.

Power input graph