40 Watt Solar Panel charging phone


Old 08-17-15, 01:15 PM
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40 Watt Solar Panel charging phone

Good Day ladies and gentlemen,
I recently scavanged a forty watt solar panel and was building a phone charger with it. I took a car charger from an unkown brand and replaced the power source with the solar panel and tested it. I used an old BLU phone in case i broke it. It charges perfectly for the first couple of minutes, but then gives me a charging error and beeps over and over loudly.

Any suggestions, fixes, or new ideas? I dont want this solar panel just laying around

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Old 08-17-15, 02:37 PM
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40 watts is huge for charging a phone. may be getting 4 amps or so.. Your probably over heating the battery in the phone. but we dont know how you hooked it up..

You need a regulated charge controller to charge a 12v battery is your best bet and use an inverter...
Old 08-17-15, 03:20 PM
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What voltage is your solar panel?

Then you took a car charger designed to output 12 volts and be powered by 120 VAC and used a DC solar panel to power the charger. Then you hooked it up to a device that needs 5 volts DC for charging. I hope you're seeing a problem there.
Old 08-18-15, 01:00 AM
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Other than just as a project and to be able to say, "Look what I did!" I see no reason to even mess with a solar charger for a cell phone.

A couple of years ago I did an experiment where I connected my Kil-A-Watt meter to my cell phone charger for about three months. The result of the test was that I used about a nickel's worth of electricity a year to keep the phone charged. Now admittedly at the time my electricity was about eight cents a kilowatt hour but even if you are paying 80 cents a kilowatt hour the cost is still less than a dollar a year.
Old 08-18-15, 01:45 AM
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Me and my friends have built a 100 W solar panel generator for a charging station. We did it with some calculations from where the sun will hit most of its light from the panel. One thing, Have you used a charger controller? This will help to limit the rate/amount at which the electric current is added to the batteries. This will also prevent overcharging. We bought some kind of charge controller which is designed for a solar panel system.
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