How do i test leds that are wired?

[reefpeeper]

I have 12 cree leds wired in series and they recently all went out. I know that it is not the driver because when switched to the driver that runs the blue leds they still do not light. So with that being said how can i test the leds to see if one or more are bad? Or does anybody have other suggestions on what else could be wrong?They are still wired in series. Thanx

 

[Reef Breeders Verified Sponsor]

You can wire 2 AA batteries together, and touch positive to negative, and if the LED lights, it is good to go. There are harnesses for the 2 batteries available at radioshack, that is what I use to test my LEDs.

 

[ReefLEDLights]

The common drivers try to maintain a constant current. If you have a loose wire or cold solder, Its possible that the driver surged and fried the LEDs

You can also use a 9v battery but I prefer a multimeter for testing

This troubleshooting link may help Trouble Shooting and things NOT to do! « « ReefLEDLights | LED Aquarium Lighting ReefLEDLights | LED Aquarium Lighting

 

[Bluewater04]

Make sure the driver is disconnected and use 2 aa batteries to test each led.

 

[reefpeeper]

I did the 2AA test and all my white leds did not light. Does this mean they all blew at once? Do i need a new driver also?

 

[ReefLEDLights]

I did the 2AA test and all my white leds did not light. Does this mean they all blew at once? Do i need a new driver also?

The driver is doing what its supposed to...Provide a constant current.

If it was fooled by a bad connection it increased current and most likely fried the LEDs. The driver should still be good. You can test it on the other string of LEDs but make sure everything is unplugged.

Its really important to ensure all connections are secure. This is why I like solderless connectors. As its an art to solder well...

Bill

 

[Bluewater04]

Make sure the driver is disconnected and use 2 aa batteries to test each led.

Sounds like the leds are fried.

 

[Young Frankenstein]

Take an Ohm meter, measure resistance touching the LED in circuit, with leads +to+ and then reversing - to + , one way you should read a high resistance and when reversed you should get continuity. If reversing in both cases show continuity or infinity the led is gone.