I had the idea to add a solar panel to a shed we have without electricity. I've always been interested in Solar technology, so this seemed like a practical application to mess with solar.
I decided this should be a 12v DC system, which would allow me to use the myriad RV solar and lighting accessories available on the market.
The rough bill of materials ended up being:
- Solar Panel
- Solar Charger
- Battery
- Light
- Some way to switch the light
- Wiring
For the solar panel, I ended up getting a 50w panel from Renogy on sale for 80 dollars. This ended up being a bit overkill for my usage, but I do hope to put more than a simple light on this circuit in the future. The mounting hardware was an additional $10.
For the Charger, I debated rolling my own, or at least using a PCB and designing my own enclosure, but most of what I found readily available was for 5v circuits to charge smaller 3v batteries. I ended up again going with an off-the-shelf product, This unit from Vicron setting me back another $80. I don't know a lot about the solar world, but this charger seems to be well reviewed and I have had no issues with it. The Bluetooth feature is nice for configuration, and I like that it is set-and-forget.
For the battery, I started with an old Black and Decker 12v hand-tool battery that I disassembled. This was undersized and the wrong chemistry as I'd learn to find out. The light would only illuminate for a couple of hours with this battery, and come winter it would not charge, which is standard for LiPo batteries. I then opted for this battery from Canbat. It holds orders of magnitudes more charge, and being AGM, can charge in sub-zero temps. The battery is again overspecced for my use, though I wanted to support a Canadian company.
For the switch, I did roll my own. I wanted something similar to a paddle switch on the wall, but with functionality to shut itself off after a set amount of time. I ended up ordering a cheap 12v timer-relay off of amazon, and using a momentary button for a PC I had on hand. The idea was to put this in a double-gang wall box, which I would run DC cables out of to the light and battery. As an extra feature, I included a USB panel that would tap the same feed as the light switch relay, to allow charging of phones if we lose power. The last bit was a 3d-printed face plate for the 2 gang box, that accommodates the panel-mounted USB unit, along with a place to hold the timer-relay PCB. Though I had many components on-hand, this can all be had for less than $50.
Last items were the Light and the wiring. The 10w RV light ran me $10, and though I probably could have gotten away with using Romex I had lying around, though I did buy some DC cable off of Amazon, 30 feet at 16 gauge running $30.
Totalling that up, we get... $250 bucks. Cheaper than hiring an electrician to run a line to the shed? Maybe, but messing around with this stuff was half the point.
I hope to do more with Solar in the future, including even getting panels for the house. I hope Nova Scotia adopts "patio solar" laws found in Europe and some places in the US, allowing people to DIY a set amount of Solar to supplement their mains. the tech is getting quite affordable, but laws are behind the times.
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