# Solar charged SLA, LED lights



## GotCoffee (Apr 10, 2006)

I'm trying to build a solar charger for a 12V 7Ah SLA battery that will power 12 white LEDs (3.5V @ 20 mA) 24-7. The LEDs are set up in three groups, 3 LEDs in two different bathrooms and 6 in the hallway.

I was thinking of series 3 LEDs with a 75 ohm resister. The max I for these LEDs are 30mA.

Does anyone know where I get a charger for the SLA of a schematic on how to build one. I'm pretty good with a soldering iron. I have been searching mouser.com for an IC that would charge an SLA and then float charge to no avail. The charger or circuit will be powered from 12V similar to http://www.siliconsolar.com/shop/catalog/12v-Solar-Battery-Charger-p-133.html

Thanks,

Ray


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## bfg9000 (Apr 10, 2006)

The $10 price of a pre-built: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=44768 makes it kind of difficult to consider building one. SLA will absorb the slight overcharge from such low currents without issue so this is already as low as float chargers go in UPSes, emergency lights and other applications those SLA are commonly used in.


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## bfg9000 (Apr 10, 2006)

Of course if you insist on fast charge + float:
http://www.arsqrp.com/ars/pages/back_issues/2003_text/0903_text/N7CEE.html
http://users.picbasic.org/projects/SolPanCtrl/solar_panel_controller.htm
http://www.uoguelph.ca/~antoon/gadgets/labc2.htm


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