What resistance to put in my led string

[symon_say]

Hi

I building some leds for an ATS, but the driver seen to have to much power and have already burn a few leds, i want to put a resistance to avoid this.

The string have 10 leds 8 red and 2 blue all in series, from what i have read red take less draw, the driver is a cheap chinese one (i have never have problem with then) that deliver 24-45V@650ma.

What resistance should i put??

[der_wille_zur_macht]

You can't (easily) add resistance to the output side of an active constant current driver in order to reduce the drive current. If you did try to add resistance, eventually you would hit the voltage limit on the driver, and behavior beyond that point would be hard to predict (it might shut down, it might strobe the LEDs, it might burn up, or you might get lucky and end up with a lower drive current).

I would suggest getting a driver with the proper current.

[symon_say]

Ok, Thanks, adding more leds can solve the problem too?? right??

[der_wille_zur_macht]

Not really. Adding more LEDs in series will have the same end result. Eventually you will hit the driver's max voltage, and after that point behavior cannot be predicted.

You COULD switch to parallel strings but that introduces a different level of complexity and would basically require developing from scratch.