Thermister protected CC devices

[purduephotog]

After killing a number of LEDs I read up on LedEngin's site about installing a thermister - GE610 I think- to prevent this.

I wired up my 14x5W ledengins and measured the voltage across them- 32.5V (which was very low). I installed said thermister- voltage is now 38.5V.

I'd like to put a couple of more LEDs in there since I can take advantage of the extra headroom... but I suppose I never thought the voltage would drop so much around that thermister. Of course, I have the thing totally encased in heat shrink tubing so I can't easily measure the drop around it.

I did measure the temperature with a HF IR Non-contact and the thermister was radiating around 210F... so I may have to install some additional thermal protection around the wiring (I'm using good quality MTW silicone wiring, then cheap 22 gauge to wire the LEDs).

Anyone else have experience with thermisters ?

Thanks Kindly-

Jason

 

[a1953mdl]

Did you get any more information on this. I think for higher power LED lighting this is extremely important. Unfortunately I can't help you any, was reading to find out about it my self.
Maybe bringing this to the top will incite a little more feed back on this subject.
Lee

 

[purduephotog]

Did you get any more information on this. I think for higher power LED lighting this is extremely important. Unfortunately I can't help you any, was reading to find out about it my self.
Maybe bringing this to the top will incite a little more feed back on this subject.
Lee

Well, I did and I didn't.

I built the device with a thermister and it is burning approximately 10V @ 1.3A. That means 13 watts is going out to heat to protect the unit on startup.

I'm probably going to cut the wires and remove it, or at least add another couple more LEDs (perhaps a 10W unit) to lessen the waste.

My coworker, a very intelligent EE, told me it was a silly idea to use one as they should be designed with better clamping, etc.

I'm using a Meanwell CC supply instead of xitanium. So far it's not had any issues.

 

[blasterman]

I'm using a Meanwell CC supply instead of xitanium. So far it's not had any issues.

"F -n- A, bubba"



Yeah, the Mean Wells are giving me less hassles as well. And a lot cheaper.

Also, you don't *HAVE* to use the LED orientated Mean Wells. The fixed voltage ones work fine if you do the math right, usually have an adjustment range, and are typically cheaper. The tend to be a tad less efficient than current regulated, but big deal.