# Solar panel

• posted

That violates the conservation of energy principle, you can't run LEDs off a battery and recharge that battery with a solar panel powered by the LEDs. LEDs are at most 40% efficient at converting power to light, solar panels are %20 (not sure) and you lose even more power in the battery. An LED array takes a lot of power more than just several watts.

• posted

Would it be possible to trickle chargle batteries of a higher voltage? ==================================================== There are very efficient (80 to 90%!) dc to dc converters that accept input volts over a 4:1 range 9 to 36 volts. A 12V solar panel is typically 21V and 0 ma or 0V at 320ma or somewhere in between like

12v and 160ma. or 14V and 130ma (about 2 watts). Check out electronics places like Jameco, Digikey to look for dc to dc converters and power supplies.
• posted

Hi,

I have a solar panel which generates a max of 2W out.

Would it be possible to trickle chargle batteries of a higher voltage?

I have a high voltage battery (12VDC...ok not that high) running many smaller low voltage LED's. As the LED's dont use much energy, Im assuming that a small solar panel can put back what the LED's took out.

If this is possible, do I need any extra's to hook it up besides a diode? Also, does voltage or current play a role in my answer?

```--
Vince```
• posted

Yes Vincent The voltage output is very important and your question cannot be answered without clairvoyance ;_) You will have to find out the voltage (output by the panel) by measurement or a nameplate etc. To charge the 12v battery it would want to be at least 14v output.

```--
Regards ......... Rheilly Phoull```
• posted

Nobody metioned power yet. Red blue and green leds have diff voltages... but .02amps and 3v will run one...thats .06watts, so a

2watt panel will run 33 leds.
• posted

Yes. A boost converter can increase the voltage. What voltage does your solar panel produce?

It depends on how much current the LEDs use. "Many" LEDs could mean

5 or 500 or ?? If the LEDs take out less than 2 watts and the panel produces 2 watts then (ignoring losses) your panel can put back in what the LEDs took out.

Yes and yes. You'll need a DC-DC converter to raise the voltage to the voltage needed for trickle charge - and you need to know how much current the LEDs use to decide whether the project is worthwhile.

Ed

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