Quote:
Originally Posted by Fat Charlie
you could probably turn your whole roof into a panel without having to know too much about electricity.
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"The General rule to calculate the average charge time:
"Take Amp/hour rating of the battery and Divide by the charger rating (in amperes) and then add about 10% for the extra time to top off the battery, i.e. Assuming You have a typical full size auto battery, it is about 50 amp hours.
"To Calculate how much time You’ll need to charge the battery with a 15 Watt solar charger You’ll need:
1. Calculate the Ampere per hour of the charger: 15 Watts /12 Volts = 1,25 Amperes
2. Calculate the division: 50 amp hours / 1,25 ampers = 40 Hours of direct sunlight
3. Add 10%: 4 hours"
(retrieved from here:
How to Use 12 Volt Portable Solar Powered Battery Chargers)
Seems useful. Maybe use a 100 watt charger, like this pretty expensive thing:
100w 12v,Semiflex solar panel,thin 2.5mm,Waterproof ! - eBay (item 260771192187 end time May-18-11 20:59:20 PDT)
This panel would nearly cover my whole roof.