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45W sounds like overkill for an RPi - I live in Scotland (55.95N) and I have a 50W panel charging a 110Ah battery in my garden shed. The battery is used to powe

by jrabone 13y ago

45W sounds like overkill for an RPi - I live in Scotland (55.95N) and I have a 50W panel charging a 110Ah battery in my garden shed. The battery is used to power a 1kW Invertek 250V inverter (150A fuses are impressive BTW) which I use to run a lawnmower, power tools, soldering station and lights (not all at once!). The lawnmower is the biggest drain (900W) and is really pushing the envelope - but in the summer I can cut 55 sq. metres of lawn once a week without any charge problems. In the winter the grass doesn't grow :) but I can run the other tools just fine. I was very surprised at just how well this system worked, but then I did splash out on a high end 50W Kyocera panel when I designed this. My only alternative would have been to bury an SWA cable across common ground and somehow run it to my consumer unit in a 1st floor flat, so I was prepared to spend £300 (as it was then) on the panel. They're a lot cheaper now.

tocomment 13y ago
How much did the system cost?
- jrabone 13y ago
  In total about £600 (this was 2 years ago); £250 for the panel, £120 for the battery, £150 for the inverter (Ebay, 2nd hand) and the rest on sundries like cable & connectors (also Ebay in most cases). I used http://www.midsummerenergy.co.uk/ http://www.midsummerenergy.co.uk/ for a lot of the bits. Note you can now get a 135W panel for £190, which is some indication of the falling cost over the last 24 months - the 50W Kyocera panel is now £80!
  - tocomment 13y ago
    So what kind of battery is it? I might want to try this. Do you have any other details? A blog post perhaps :-)
    - jrabone 13y ago
      It was an Elecsol 100Ah leisure battery. The equivalent would be http://midsummerenergy.co.uk/buy/Sealed-Batteries/PM-110.html http://midsummerenergy.co.uk/buy/Sealed-Batteries/PM-110.htm... Other bits were a Morningstar SunSaver solar regulator SS10 and a Nasa Clipper BM1 Battery Monitor (unnecessary extravagence - don't bother!). I also added a couple of 12V fluorescent lights powered from the SS10 so I didn't need the inverter running just for light. It's a pretty simple set up, the hardest part is making up the high current battery cables - the clamps, fuse holder and connector to the inverter are pretty substantial to handle 100A. I mounted the panel on the roof of the Apex shed with simple aluminium brackets. The wiring is pretty simple (more complicated by the battery monitor which has a 100A shunt resistor in the negative lead to monitor the load current). I uploaded a pictorial wiring diagram at http://i.imgur.com/UX4Y29o.jpg?1 http://i.imgur.com/UX4Y29o.jpg?1 for you.
      - tocomment 13y ago
        That's great thanks! I'll let you know how it goes.
tocomment 13y ago
So if I got a bigger panel and needed more power would you say to buy a second battery? Would I just hook it up in parralel?
- jrabone 13y ago
  If you need more power you have 2 options. You can add more batteries in parallel and increase the size of the cables to take the higher current, or you can go to a 24 volt system which means you can use the same cable. 24 volt components are maybe harder to find though. My system is really intended for short periods of peak power (say 30 minutes a week running the mower). It was harder to find cheap inverters to handle more than 1kW at the time too.

by jrabone 13y ago

tocomment 13y ago

How much did the system cost?

jrabone 13y ago
In total about £600 (this was 2 years ago); £250 for the panel, £120 for the battery, £150 for the inverter (Ebay, 2nd hand) and the rest on sundries like cable & connectors (also Ebay in most cases). I used http://www.midsummerenergy.co.uk/ http://www.midsummerenergy.co.uk/ for a lot of the bits. Note you can now get a 135W panel for £190, which is some indication of the falling cost over the last 24 months - the 50W Kyocera panel is now £80!
- tocomment 13y ago
  So what kind of battery is it? I might want to try this. Do you have any other details? A blog post perhaps :-)
  - jrabone 13y ago
    It was an Elecsol 100Ah leisure battery. The equivalent would be http://midsummerenergy.co.uk/buy/Sealed-Batteries/PM-110.html http://midsummerenergy.co.uk/buy/Sealed-Batteries/PM-110.htm... Other bits were a Morningstar SunSaver solar regulator SS10 and a Nasa Clipper BM1 Battery Monitor (unnecessary extravagence - don't bother!). I also added a couple of 12V fluorescent lights powered from the SS10 so I didn't need the inverter running just for light. It's a pretty simple set up, the hardest part is making up the high current battery cables - the clamps, fuse holder and connector to the inverter are pretty substantial to handle 100A. I mounted the panel on the roof of the Apex shed with simple aluminium brackets. The wiring is pretty simple (more complicated by the battery monitor which has a 100A shunt resistor in the negative lead to monitor the load current). I uploaded a pictorial wiring diagram at http://i.imgur.com/UX4Y29o.jpg?1 http://i.imgur.com/UX4Y29o.jpg?1 for you.
    - tocomment 13y ago
      That's great thanks! I'll let you know how it goes.

tocomment 13y ago

So if I got a bigger panel and needed more power would you say to buy a second battery? Would I just hook it up in parralel?

jrabone 13y ago
If you need more power you have 2 options. You can add more batteries in parallel and increase the size of the cables to take the higher current, or you can go to a 24 volt system which means you can use the same cable. 24 volt components are maybe harder to find though. My system is really intended for short periods of peak power (say 30 minutes a week running the mower). It was harder to find cheap inverters to handle more than 1kW at the time too.