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Solar powered led problem? Answered

I have an issue with my solar powered lights. I have this solar panel...


and a radio shack 12v 5ah battery. The leds arent even pulling 1amp and I have only used them 2 or 3 times. The solar panel claims to have discharge and overcharge protection but after not using them for about 2 weeks the battery is reading only 6-7 volts....I tested the panel in the sunlight and it read about 18v output...

I have the polarity correct and the panel is hooked directly to the battery and from the battery it is hooked directly to the lights with a switch. Now maybe that is my problem? Im not sure. Most projects I see have a charge controller in between but they have higher watts..so idk.

Would really like some insight into my issue if I have one besides maybe the panel being bad.

These are my lights....


That panel and that battery should work.

First make sure the battery will take a 12 volt charge it may be new, that doesn’t mean it is good.

Second the solar panel may be draining after dark if that is the case, add a diode. A 1N5817 should do it will carry 40 volts and 1 Amp.

Like this solar light schematic I hope it is the same idea as yours, after dark some solar cells and panels drain the battery if not in use this circuit should prevent that if the built in has stopped working.

Last make sure the solar panel is getting a full days light, some solar systems need 10 hours, this time of the year we get only 8 hours of light.


Solar lights Answer.gif

Thanks for the answer. I have a feeling the enternal diode has failed. I put the solar panel and the battery in my window yesterday and it was a cloudy day and the battery read something like 7.06 volts when I left and when I came back later in the day and darker it read in the 6 volts. So I also think the solar panel is draining the battery. I do wanna possibly run some other lights off this also in the future so I might just go get a bigger panel/controller combo.

that's a 1 watt panel, in full summer, noon sun. which, even then is less than 100ma of charge, so for every hour the lights are in, the FULL SUMMER SUN, PERPENDICULAR TO THE panel takes 6 hours to charge the battery back. There in lies your problem.

What kind of battery is it?

The solar panel isn't going to have any kind of charge controller. It will have a protection diode built in so a battery doesn't feed power into the panel and damage it. The above panel is meant for trickle charging a 12V SLA battery. Meaning if your using the battery on a regular basis the panel will not be able to keep up. An SLA battery is considered dead when it's down to about 10.5V or less. It would take that panel several days to fully recharge the battery.

It is a ups/alarm battery.. The lights will only be used maybe 1-2 times a week for maybe 2 hrs at a time. I used the lights one night and tested the battery afterwards and it only dropped like .02 volts. If I remember correctly the leds only pull around 500ma total. Ok so do you think it overcharged the battery and just killed a cell or two in it? Cause with the multimeter it only reads around 7 volts.

May be overcharging damage. Damage could be battery wide or just in a cell or 2. Doesn't really matter since it may have rendered the battery useless once it's fully discharged.

OK thank you for your input. Ill go get a charge controller and battery from radioshack and give it a shot!!