Now that is has been a full 4+ months since my previous post I’ve finally made some progress with my solar power supply.
I have picked up several pieces that are key to getting a fully off grid low voltage power supply. I was able to get a Kyocera KC50t Solar Panel, a Xantrex c35 Charge Controller, a DC breaker box and breakers, interconnect wire, and mounting hardware.
I mounted a piece of 1/2″ plywood to my garage wall as a backer board, and there I mounted the DC breaker box along with the Xantrex C35 about half a foot above that. Then onto the wiring from there.
Wiring together all of the components took longer than I had expected. Due to the distance of my panel from the electrical components I needed 10g wire. I was actually right on the cusp of needed 8g wire and the cost jump was double, so I was happy to be in the 10g range. After some effort I finally got everything wired together.
So now I have 10g leads from my battery pair to a DC breaker in the box as a cutoff. From there more leads went to the Xantrex on the battery terminal and common ground. Then another lead from the PV Array terminal and common ground on the Xantrex to another DC breaker. From the other end of that breaker was my long lead up to the roof where the panel would be mounted. Also I have incorporated a ground wire interconnecting all of the pieces together with a grounding stake that is just outside my garage.
After actually trying to build a mount on my own vs. buying one, I ended up returning my mounting hardware and purchasing a purpose built mount. I’m much more comfortable with how this worked, and I have more confidence in its construction. I think that I could have build the mount myself, but it was much easier to just assemble than to visualize how to do it without a reference.
Once I had the factory mount in hand, the remaining tasks went pretty quickly, and I was ready to mount the panel on the roof. I gathered my tools, my hardware for mounting to the roof, and a tube of asphalt/roof patching compound to weatherproof the holes I needed to drill to lag bolt the panel to the roof.
Once on the roof I was able to adjust the mount to a setting that was pretty close to the angle that I wanted. (More on the angle later) I then was able to use my stud finder to locate a stud to drill the holes for the lags. The other end of my mounts did not fall on a stud due to it being ~24″ across which is not the distance for roof joists (rafters?) I slathered on the asphalt compound and secured the panel with the lag bolts and washers. The finished result seems fairly secure and sturdy so I have confidence that it will stay put and not leak, I hope.
As for the angle at which I mounted the panel, I had found a great blog post that gave formulas for determining the best angle to mount panels based on your latitude, and seasonality. I decided to go with a full year angle to not require any adjustments on the roof which ended up being ~37.5 degrees.
And now for the turn on! Back in the garage I flipped the breaker for the battery bank, and after a few minutes the Xantrex started blinking. I then flipped the breaker for the PV array and I was up and rolling. I used a volt meter to test the voltage inbound from the panel which measured a strong 20v. I also tested the voltage from the battery bank lead which showed 12.8v. The Xantrex was blinking showing a charging status.
I was then able to start connecting some loads to the setup. I hooked up my HAM radio as well as a couple of 12v chargers such as a phone charger etc. I also have some 12v LED task lighting that I’ve hooked up at my workspace for my radio rig. Everything has been working great and I have not noticed any fluctuations in power.
I haven’t been using it long enough to know how much my batteries are being drained, and/or how long it takes the solar to recharge it fully. I’m not exactly sure yet how to figure that out either, so I’ll have to do some research I guess. If anyone has any ideas let me know!