To help people get more use from our Street Library, we’ve been toying with lighting it overnight with LED lights. The first attempt was rather pretty but completely impractical – AA battery-powered fairy lights on a very long string. It looked like family fireflies had taken up residency in the Street Library until the batteries ran out – every other day. We switched to rechargeable batteries. So far so good, but changing the batteries have gotten tiresome.
But if a problem is worth solving, it’s worth over-solving by putting a 12v solar panel on the Street Library roof with 12v rechargeable battery, LED light strip, and a solar controller to connect it all together. As I understand it, the solar controller regulates the input from the panel into the battery and lets the battery power the LED lights – all at the same time (that’s electrical engineering for you I suppose).
Before getting stuck in, it’s worth noting that installing all the paraphernalia for the LEDs is probably easier while you are assembling your Street Library kit. It can be done once installed – it just makes for a more rugged installation. Each installation is going to be different depending on your Street Library. Our Street Library is The Shed and we bought the kit version – https://streetlibrary.org.au/p/kit-shed/. We live on a south-facing block (the solar panel is on the north-facing roof panel of the library) and you will have to assess your own location as to the best place to mount the solar panel for the best solar production.
What you’ll need to put your Street Library up in lights (Jaycar – part numbers included).
- 12V 10W Solar Panel with Clips CAT.NO: ZM9051 – jaycar.com.au/12v-10w-solar-panel-with-clips/p/ZM9051
- 12/24V 10A Solar Charge Controller with USB – CAT.NO: MP3750 – jaycar.com.au/12-24v-10a-solar-charge-controller-with-usb/p/MP3750
- 12V 6Ah SLA Battery – CAT.NO: SB2485 – jaycar.com.au/12v-6ah-sla-battery/p/SB2485
- Ask the staff at Jaycar for some Female Spade terminals to make the connection to the battery secure.
- 8mm White LED Solid Strip Light, 12V CAT.NO: ZD0461 – https://www.jaycar.com.au/8mm-white-led-solid-strip-light-12v/p/ZD0461
- Potentially some cable appropriate for the job – again ask the staff at Jaycar, but you might also, use the cable that comes with the Solar Panel (it’s pretty long and can be cut down)
- You’ll also need something to hold the battery in the roof cavity – we used square plastic brackets from the hardware store for securing rectangular downpipes to walls. bunnings.com.au/icon-pvc-square-open-wall-downpipe-bracket_p4775651
- Some good wire strippers would also be handy. I picked these up from Jaycar – jaycar.com.au/heavy-duty-wire-stripper-cutter-crimper-with-wire-guide/p/TH1827 – but you could use a sharp knife if you don’t need them for more than this job alone.
Included with the solar controller is instructions to connect everything together. You will have 6 wires to connect to the controller to get everything working. The solar panel has a very long cable so if you might reuse some of that depending on how and where you mount the panel.
The cable attached to the solar panel is made up of a blue and a brown lead ending in red and black crocodile clips. Take note of which lead ends in which colour clip so you can connect the positive and negative leads correctly to the controller. If you’re using the remaining cable from the panel – ie more brown and blue – remember to be consistent in which is positive and which is negative.
You’ll need to terminate leads in the female spade terminators so you can easily connect the battery.
For the LED light strip, you can cut the strip down from the roughly 6 “modules” it’s composed of, to something a little more manageable (this will also lessen the power draw, but might not be something worth bothering about in reality).
Mounting everything is really the tricky bit. As luck would have it, our library faces south so we mounted the panel on the north side of the roof to get sun all day long. We had to jury rig some screws onto the panel to then allow me to secure it to the roof – and don’t forget the hole for the cable into the solar connector (and some Selleys All Clear to seal it and prevent any water getting in when it rains).
The battery is awkward to install. We chose to attach it on one of the sides to keep the connectors away from small hands (just in case). If you get one brack fully installed, and the top of the second, you should be able to slide the battery into place (don’t forget to attach the leads first) before securing the bottom of the second bracket.
The solar controller attaches easily with 2 screws.
The LEDs have an adhesive back, so mounting them is straightforward – though we would suggest using a little more Selleys All Clear for a longer-lasting job.
Once it’s all installed, you can turn the lights off so that the battery is not being drained at the same time it’s being recharged. We chose is a pretty big battery, so we can run the lights 24/7 and not go below 3/4 charge even after multiple days of bad weather.
Ultimately, you need to make sure that the solar panel is mounted in an appropriate place that gets lots of sun throughout the year to avoid worrying about power production and consumption.
This was a bit of an experiment and a learning experience. The cost is probably higher than it needed to be – approximately $150 (not including coffees and mental gymnastic ) – there may be some reduction possible if you use a smaller battery and/or solar panel.
All in all, it’s relatively straightforward to shine some light on the books in your Street Library. We think this has added value to our Street Library and like the idea that someone might grab a book late at night on their way home.