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Simple solar powered lights with a battery

nabberuk

Jul 25, 2012
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Jul 25, 2012
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hi,

I have some fairy lights the are powered by a 3v battery, also I have a solar cell that's 6v and 4.5w/520mA. I would like to charge a battery pack (haven't got one yet, was thinking of a couple of a cells in series and parallel) with the solar and then power the lights at dusk - I believe I can use the solar to detect dusk.

Other than that, I'm pretty stuck so if anyone could point me in the right direction
 

donkey

Feb 26, 2011
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Feb 26, 2011
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1,301
ok so how skilled are you?
what size battery you looking at? amp hours matter
what type of charger yo using? lipo and standard batteries (AA< AAA etc) use a special charging circuit from memory. SLA batteries take what you give them.
what are you going to do with the 3volt battery?
 

nabberuk

Jul 25, 2012
9
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Jul 25, 2012
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9
Not very skilled at all when it comes to electronics!!

Looking at standard AA batteries, unsure on the amp hours but would need a 4-5 hour run time. During the day the solar cell would charge the batteries.
 

Alec_t

Jul 7, 2015
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Jul 7, 2015
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White LEDs have a forward voltage of at least 3V, so you'd need 3 or 4 AA cells in series to drive them directly. Alternatively a DC-to-DC converter could step up the voltage of a single cell (as is done in most garden lights).
Your solar cell rating is probably an optimistic one for full sun at the equator :), so don't expect 6V throughout the day.
 

nabberuk

Jul 25, 2012
9
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Jul 25, 2012
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9
Yeah I guessed that I wouldnt get the full 6 volts, I've been testing it in our gloomy weather and I've been getting around 4.5 volts.

On the old solar that came with the lights, it contained a single aa cell so it was stepping up the voltage, it had other circuitry in to switch between flashing etc that I'm not fussed with.

So I though I would build a separate one. Just not sure on how!
 
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