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Would my solar cell setup work?
Actual question at the end, I will first explain,
At the moment, this is just a proof of concept, i'm only wanting to know if my thinking is correct. Basically, i want to make my own UPS on the cheap £50ish, compares with 100s for a compplete system.
I would buy the following:
12v Solar Cell for charging 0.125mA
12v 8Ah Battery
150 Watt inverter (supplies 220V from 12V)
1. How long would it take for that solar cell to trickle charge the 8Ah battery to a full charge?
2. If my computer uses 65W power, would this calculation be correct to find the maximum run time off the battery:
P/V = I so 65W/12V = 5.5amps to run.
For an 8Ah battery, 8Ah/5.5A = 1.45
1.45*60= 87Minutes or 1h27 maximum run time from a full charge. Is this accurate? Thanks
1 Answer
- billrussell42Lv 71 decade agoFavorite Answer
1) 8 Amp-hr battery holds 8 amps for 1 hour or 1 amp for 8 hours worth of charge. That means 0.125 amp will charge it in 64 hours. But in reality it will be over 100 hours due to losses. That's 65-100 hours of bright sunlight with the sun directly perpendicular to the solar cell.
Batteries have leakage current. If that is, for example, 10mA, that subtracts from the charging current and adds to the charge time.
2) 8 amp hr battery x 12 v = 96 watt-hrs. that means a 65 watt load will last 1.5 hours (96/65), but subtract 20% for inverter losses (more if your design is not as good as a commercial one) and you get 1.2 hours.
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