Maybe the Chinese company who made the LED strips also does not know how to calculate the current. Then the LEDs and/or resistors will burn up soon.

 

There is only 1 resistor for every 3 LEDs

That makes perfect sense. When using LEDs, you want to put as many in series as you can, while still getting them to light. This drops most of the voltage across the LEDs, something around 3V each (less for reds), turning that drop into light energy. You want to minimize the voltage drop across the current limiting resistor, since that drop is all turned to heat instead of light.

IMHO, you may want to add a bit of extra resistance into the entire rig to help it last longer. You can add up the number of 3-LED strings you have, combine the current thru all of them (I = ∑LEDs/3 x 0.020A), and choose a resistor to drop maybe 1V at that current draw, ∆V = I•R. The resistor will need to be rated for I^2•R watts of heat dissipation, and you'll want to at least double that rating for safe operation.

 

Thank you very much to everyone who replied, your advice is very helpful.

I think I found the right datasheet for the SMD LEDs used in that strip and the forward voltage drop is between 2.8V - 3.6V. Most likely around 3.2V typical.

It makes it much easier now. Lets see what happens now.

 

Maybe the Chinese company who made the LED strips also does not know how to calculate the current. Then the LEDs and/or resistors will burn up soon.

How many Canadian companies are the making LED's? Where can they be bought?

 

I buy LEDs made by Agilent but now is called Avago (divisions of Hewlett-Packard) and from Philips Lumileds (who also were Hewlett-Packard). Hewlett-Packard is an American company.

I don't know a Canadian company who makes LEDs. Maybe I am the only Canadian guy who buys LEDs?