Calculating Solar Power Outpower

flutsy

Firstly apologies if this is not in the correct thread.

I was wondering if someone could tell me how to calculate how much power a 13w solar briefcase would make? Or to fully charge a 85AH leisure battery? What figures do I need? Or does anyone have a dummies guide type website I could look at to learn more?


Thanks

espresso

flutsy wrote: »

Firstly apologies if this is not in the correct thread.

I was wondering if someone could tell me how to calculate how much power a 13w solar briefcase would make? Or to fully charge a 85AH leisure battery? What figures do I need? Or does anyone have a dummies guide type website I could look at to learn more?


Thanks

Instructions/specification here.

flutsy

Thanks for the quick response and great link. Unfortunately I know nothing about electricity so that doesn't mean a lot to me.

Any equations that I would use to calculate the length of time?

espresso

flutsy wrote: »

Thanks for the quick response and great link. Unfortunately I know nothing about electricity so that doesn't mean a lot to me.

Any equations that I would use to calculate the length of time?

Those instructions recommend a 12V battery of 10 - 40Ah capacity.

The maximum output is 13W, so for a 12V battery the charge current would be approx 1A and this would take about 85 hours to fully charge your 85Ah battery.

The maximum output of 4A as stated is for the 3V charging output. It may well do a reasonable job of keeping your battery topped up, depending on your intended use/application e.g. how much current is drawn and for what period of time.

Cardew

I would also put emphasis on the maximum(as in the post above) output being 13 watts; and bear in mind it will only charge during daylight and most of the time will not produce anything like 13 watts.

85AH is a large capacity battery and really the solar briefcase is not up to charging something that big.

The main purpose of these solar chargers is to charge a mobile phone, and at a pinch a laptop, if you really can't access mains - say on a yacht. Even then it will take several hours(on average) charge to enable a laptop to run for an hour.