How long does it take to charge a 12v deep cycle battery with a 10 watt solar panel?
I want to also know if the 10 watt rating on the solar panel is 10 watts per day or is it constantly adding 10 watts? Is there a time which the 10 watts is being added like 10 watts per second or 10 watts per minute and so on?
120 hours of peak sunshine, I’d say give it a month.
Normal power is measured in kilo watts per hour. It sounds like 10 watts would be very small to do anything.
Watts is a measure of energy per second. IE joules per second. 10 watts = 10 joules/second
Car battery capacities will be measured in mAH (milli-Amp hours)
capacities vary greatly although they will still take a fair while to get charged by such a tiny power charger.
a 10w solar panel means at peak efficiency ( high noon, panel pointed flat at the sun, hitting it at 90 degrees), you will get 10 watts (at any given second).
Watts = volts x amps
a 12volt battery needs an "incoming" current of at least 13 volts to charge it; 13.5 volts is better.
so if the output VOLTAGE of the panel is less than 13 volts it wont do anything.
Even if it is, 10 / 13.5 = .74 amp.( three quarters). It will take forever and a day to charge a deeply discharged deep cycle battery……….
consider that a small 110v battery charger is putting out 3-5 amps ( or 3 x 110 =330 Watts) and the alternator on a car is putting out 20 to 50 amps at 14 volts ( 280 to 730 Watts).
It will put out 10 watts in full sunlight at noon, less at other times of the day. That means 0.83 amps, so just divide the battery capacity (in amp-hours) by 0.8 and you’ll get an approximate charging time under full sun.