Why is my 2009A-SHO LED Driver gets so hot on CREE p4?

Hi guys,
I have just tried out the 2009A-SHO LuxDrive MicroPuck 3V with my cree XR-E P4, and realized the LED Driver gets very hot. The LED driver has 500mA output, and I was only using 2 AA batteries (3V total). Is the driver suppose to be hot when it in use? I'm a noob on flashlight, so please let me know if this is normal for the driver to be so hot. Because I'm afraid it gets burn out. :huh:
Thank you!


-lightbug-

How do you have it configured? It's either a boost (1-3V source) or buck (4-8V source) configuration typically. Unfortunately, you are "in-between", 2xAA batteries (alkaline), new, will be over 3V to start with typically around 1.7V each for a total of 3.4V. This puts the driver module "in-between" modes and it's probably doing a lot of internal switching trying to compensate, or it's being overdriven in it's "boost" mode from it's design. Once the AAs fall below 3V total, it'll probably cool down some (how hot is hot? Can you hold it in your hand in operation?)
Best bet, switch to NIMH rechargeables which will give you an initial voltage of around 2.6-2.8V off the charger (total) and will run at a stable 2.4V until near the end of their charges. I would NOT run Lithium primary 3.0V cells, as these will start over volted, maintain that situation much longer, and not fall below 3.0V for quite awhile (relatively, but figure at least 25% of their runtime will be at or above 3.0V).
Anyhow, not much details in your post, if it's not too hot to hold, it probably won't burn out, but if it's getting that hot (or you smell something), somethings way wrong.
If it's wired in buck/boost mode, it'll run hotter as it's much less efficient, but still, the rest above applies.
Folks with more experience with that driver feel free to pipe in, these are just my thoughts on where the problems may lie, could be totally off base.

does the puck have a switching mechanism to boost/buck modes?
i thought that depended on how the puck was connected...

Christexan said:

How do you have it configured? It's either a boost (1-3V source) or buck (4-8V source) configuration typically. Unfortunately, you are "in-between", 2xAA batteries (alkaline), new, will be over 3V to start with typically around 1.7V each for a total of 3.4V.

Click to expand...

Open circuit voltage for an alkaline cell is only going to be ~1.6V, max. As soon as you hit them with a 500-plus mA drain, they'll drop rapidly (in less than 5 minutes) to below 1.5V for a closed circuit voltage. Unless you move to a different chemistry like a NiOOH cathode found in Duracell PowerPix, or lithium-iron disulfide cells, you won't be over 3 volts CCV for very long with at that level of current draw.

At over 500mA current, you'd be much better off using NiMH cells, anyway, and if you did have an issue with overvolting the puck, it would definitely go away with a pair of NiMH cells would be running at 2.5V CCV.

Thanks for the input guys, appreciated here .

To Christexan:
It is quite hot, barely can hold it in my hand when the batteries are fresh.
However, I don't see smoke comes out nor burning smell.
The MicroPuck is a lot cooler after 15 minutes use of the batteries.
So I guess your assumption of the new batteries going over 3V is correct

Thanks again!

Sorry if I am hijacking this thread, but the standard MicroPuck (even the older and original 350mA versions) can handle a buck mode, too? I ordered mine years ago from LEDSupply.com and they only gave info about its boosting capabilities. When (and if) it bucks the voltage, is it only a safety feature for fully charged batteries, or is it designed to handle something like a 5V power supply? This is a noob question I am sure, but I never heard much about the MicroPuck in the past and never gave it much thought. Also, does it have to be wired differently? I dont own it anymore, but if it has some nifty features as a buck mode, I will get another. Thanks!


-Tony

Micropuck 2009A (350mA version)