Hi,
I bought a solar panel a year ago and didn't use until today. I bought an LED light that has around 62 LEDs that consumes 15watts with a 220v converter how can I hook the LEDS to the solar panels do I need resistors? What size? How many?

I opened tbe LED inclosure and took the attached pictures. I found 62 LEDs that are connected in parallel -am not sure- the whole thing is 15 watts and 1000lm. This is everything I found so far. I wish it is enough to start. Also, the PV is 85 watts and 24 volts. I usually get voltage in the range of 19.

I'll NOT use the supplied LED controller instead, I'll hook the LED strip to PV directly. The problem is how to do so? What resistors do I need? How to connect them?

 

The pictures

 

Sorry for the duplicated picture.

 

May be a problem. The controller says 300 ma. and 15 watts. OK so it is good for the led's that say they are 12 watts. So using P=IE it would say about 40 volts to the leds.
The leds appear to be in series, but 40 volts would not be enough for 62 of them. So something doesn't add up. Can you measure the voltage to the leds?

 

Ronv,
Thank you for the prompt reply. I measured the out voltage of the controller and it showed strange reading. It increases from 5.xx to 30.xx in 5 seconds after that it decreases from 30.xx till 5.xx in another 5 seconds and so on.

 

Was it connected to the leds?

 

Was it connected to the leds?

No ronv it wasn't connected.

How should I measure the voltage? Is it between the positive and negative of the LED strip? Or in the wire before the LED strip?

 

The voltage is 37.3

 

Do you still have the specs on the solar panel? If it has enough power you could use a constant current boost regulator to raise the voltage.
You can find them pretty cheap on ebay.

 

I don't have the specs but it is 85 watts and 24v.

Can I use dc-dc buck converter?

 

No, It needs to boost from 24 to 37 and have constant current control.
They are not so cheap at 37 volts, but here is one example.
http://www.amazon.com/Autek-Constan...nstant+current+boost+converter#productDetails

 

Great ... I'll wire the LED directly to the PV using this booster regulator isn't it?

BTW, thank you thank you thank you ronv.

 

Not quite so fast.
The output of the solar panel goes to the input of the boost circuit..
Then you need to adjust it.
What would be good for this is a resistor of say 1000 ohms and 2 watts or more.
Then adjust the voltage to 38 volts while the panel is in the sun.
Then attach a small lamp - like a seven watt Christmas tree light and adjust the current adjustment to 290 ma.
Now you can hook the output up to the leds.