I am going to build my panels, I do not how many I need nor do I know how many battery’s I need, also inverter. Can you give me the answers? I have a 2 bedroom home with 2 bathrooms. A shop with plenty power tools. 2 ref and 2 freezers,washer and dryer also. What am I going to need?
Thanks

Best answer:

Answer by Peter W
OK – some rules of thumb:

10 watts per square foot, unless you go to amorphous-crystal cells – then you may get up to 15 watts per square foot.

Storage should be three times (3 x) the average load in your house. The average load may be calculated from your appliances, frequency of use, lighting load and heating load.

Your solar panels must be able to deliver at least 2 x your average load in order to actually store power as well as meet your needs.

Commercial installations less subsidies are typically $ 10/watt, fully installed + storage but including the inverter. Subsidies will cover most of this in some locations. So check your area.

So: if you have an electric stove, electric dryer, general lighting and a shop with various 20A motors, television, freezers, refrigerators and so forth – 50A max on the stove. 25A on the dryer, 25A on the water heater – allow 40A for everything else. comes to 140A peak – average (rule-of thumb) is about half that. 70A. You are a heavy electric user as compared to most individuals.

At 220V, that comes to 15,400 watts. Times two, and rounding comes to 30,000 watts of capacity required to meet 100% of your needs or 30KW. Roughly 3,000 square feet (30 square meters) of panels.

Battery Storage at using 100AH batteries comes to (working backwards and allowing a 15% inverter loss and not wanting to kill your batteries) – will require forty (40) 12V storage batteries in parallel.

And why it is that most installations are to supplement power only – and not replace 100% of the requirements.

You are looking at an unsubsidized cost of around $ 100,000 +/- if you do 100% of the labor yourself. About $ 8,000 in the storage system alone. And if you do this yourself, you will not get any subsidies.

Know better? Leave your own answer in the comments!