diy solar

diy solar

Basic solar setup to power lighting in shed

Apples12

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Joined
Dec 8, 2021
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Hi all

I'm in the UK and I'd like to spec and build a small solar power system to power some lights in my outbuilding, the building is 6m x 4m and I think the total lighting will be 8 x 10w (this is a gross over estimation, I will fit standard bayonet fittings and use individual switches to turn on what I need)

It would be nice to be able to power basic power tools like a circular saw (I have a 1200w one) but this is far from essential.

Where do I start?

I know I need panels, controller, inverter, wiring, batteries.

Any help is appreciated

Thank you
 
Maybe skip the inverter. I have 300 watts solar, a little charge controller, 100 amp hour LiFePo battery, a small Blue Sea fuse block, and what we in the States call cigarette lighter 12v plugs.

Ryobi makes a little 12volt charger with a cigarette plug.

This gives me access to dozens of light tools, work lights, compressor, radio, etc. really an impressive lineup of 18v tools. The brushless stuff is quite nice. And you can take the batteries home to charge if you have a lot of work and the solar can’t keep up. Though 2-3 of the big ryobi batteries go a long, long way.
 
First, the UK has crap sun half the year.

Solar seems to be pretty good Apr-Aug.

Check out this guy's challenges:


First and foremost... There's an energy audit in the Resources section. Fill this out. List your items, their power consumption and the daily hours of use. Find your demand FIRST.

Second, and you'll need it for the final steps of the spreadsheet, use PVWatts to determine your available solar for your location. It even factors in average daily weather for the monthly calculations. You can even simulate an array based on power, tilt, orientation and efficiency.

Once you have all that, you can identify your needed solar power, inverter and battery capacity.
 
Due to your location I'm guessing you don't see the sun for weeks on end at times? If that's the case you'll need all the panels you can fit, extra battery capacity, and a way to charge the batteries that doesn't require the sun like a jump pack or extension cord.

You'll need to guesstimate how many hours a day you're going to be running that 80w of lights. That'll tell you what you should plan for battery capacity wise. Then take that number and multiply by number of days you want to run that without sun.

Third step is budget (because up until now you've just been doing math on paper which is cheap) because steak sounds great until your wallet says hamburger. Are you going to want to spend $750 on a charge controller when a $150 unit will do more than enough? How much are you going to have for batteries? Are you springing for LiFe's or are you using leisure lead acids?

After your wrist gets tired from writing all this down, the next step is to whip out a tape measure and figure out where you're going to stick everything. The panels are easy, you have X-meters of roof space. Where are you going to stick the batteries? How about the inverter? All the parts will need a home somewhere.

The last prep step, now that you have a plan and a budget, is to put together a wish list and a rough diagram of what you're looking to do and start a therad here for everyone to look at. The folk here are happy to help and having all the homework done ahead of time will earn you brownie points. Let them figure out what you missed, because we ALL miss something our first time. :)
 
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