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How much solar panel watts and battery amperes are required

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Member level 3
Oct 5, 2012
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Salam to All

I want to make a solar system
DC load is 12Ampres (12v 24 watt Six Energy Savers)
I want to run these for 18 hours

Plz guied me how many Amperes of battery and how many watts of solar panel are required??????????? that may full the battery and run the energy savers as well simultaneously

I m form Pakistan Lahore, Here it is sunny Enough.

"Sunny enough" is not enough to start your calculations.

Amperes, you need roughly the 12A (derated for end-of-
life voltage sag @ load). It's ampere-hours that cost you
in Battery Land. Your raw Ah is 12*18 or 216Ah but this
also wants derated for capacity aging and for capacity
to ride out some number of days at minimum isolation.
This is locale-dependent, and see comment #1.

Then you have to come up with a peak-sun-equivalent
insolation hours in which to replenish that battery bank.
I'd say 6h max for a fixed panel, no more than 9h for a

So if I wanted to accommodate 50% aging as the end
of service life, I'd have a 532Ah battery bank and if I
wanted to ride out a worthless day here and there, make
it 1000Ah or more.

Then to charge that fully within the 6h peak-equivalent
of a good day, that's 167A of panel output plus the 12A
base load (assuming you want whatever it is, to work
in daytime) or 179A charging current at 13.5V or so.
That's not something most batteries will want to see
for long, you need to charge at C/4 which is kinda high
for a lot of rechargeables. Something you need to look
carefully at, but won't see rated in the short form of
most battery specs - you may have to drill down into
applications support material, and find that charge
efficiency and/or service life are badly impacted by
high rate charging and need to be accommodated in
your derating calcs.

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