Re: problem with 3x cree
Can you hook up the LEDs to a lab power supply? A power supply you can adjust voltage and amperage? I would go ahead and hook up the LEDs directly to a power supply and see if they light up. You can also do a very fast touch of 3 LiIon cells and see if they light up. With three LiIon you are exceeding the Vf of the LEDs so you can't run them for too long that way. This would tell you if the problem is the LEDs.
What batteries are you using, what set-up (voltage, etc?)?
Sounds like may be the LEDs may have gotten too much juice and burned one up.... But need further information.
If you have multiple volt meters, you can hook one up before and after the driver, check amperage as well, etc...
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