Monday, 13 August 2018

solar shed lights

To me its a no brainer that solar energy just suits small scale projects which don't need to be "on the grid". So with that in mind I thought I'd show you where I'm up to with my small solar shed lighting project.

Some time back I put this small 10W panel on my shed roof, with two things in mind:
First keeping the battery of my pajero topped up and in good order when I went over to Finland for a few months (meaning I wouldn't come home to a dead battery) and
Second being the basis of a lighting power source because running power down to the shed seemed like an enormous pain in the wallet for just a bit of used some times lighting.

So I needed for this project:

  • LED lights (I sort of made them)
  • a battery (scrounged an old flattery from a mate)
  • a IR movement sensor (so as to automatically turn it on)
  • some patience
I made the LED lights by gluing LED strip (bought of eBay for $15 for a 5meter roll) onto some 1 meter lengths of angle aluminium.

This results projecting the light out in a nice diffuse manner basically at the same coverage as the angle, the side reflects quite well and so you get a nice fan. It has the added bonus that acts as a heat sink for shedding the heat from the LED's and helping prevent the glue from separating from the strip.

I then mounted the strips at the tops of the walls, so as to shine light down where I need it (which isn't on the roof of the car all that often).

...and actually when you stand back you can hardly even see they are there.

So that the lights aren't on all the time I've got a small PIR movement sensor after the controller 12V output to turn the lights on when I walk / drive into the shed. As you can see, its just wired roughly at the moment...

The controller is quite interesting, it's very well priced and has some good features. Many online reviews have slammed this little guy because its not MPPT ... well so fucking what? I'm charging a single battery from a 10W panel and MPPT would bring what? 10% more to the table? I could achieve heaps more just stepping up the panel size to 20W...

The pay back is its fucking cheap and has some great features which the online reviews seemed to ignored, perhaps because they don't "get it" in terms of usage (just testing and spec sheet gazing).

What I like about this controller is that you can set a bunch of features:
  • to only engage the load (12V output) after sunset
  • to optionally engage the load after sunrise
  • to individually set how long the load should be available for after those events
  • manually set the battery protection level voltage (the voltage it cuts off the load to protect a battery from over discharge
  • manually set the battery charge shut off level (where it just applies a tiny mA float)
That it will handle a 10A load makes it all pretty good for $30

So, how does it work?

There's still things to do, for example I'm yet to:
  • add a 12V Li-ION battery (which will be much smaller and probably last ages given the loads)
  • mount the controller and PIR onto a board for making it look neater
  • make up an adapter to allow me to charge the battery in the car still, (which would then also run the lights), so that when I am not using the car for a while I can just switch it over to charging my car battery (so its dual purpose)

I'll link to that when I get that bit done.

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