Poof'd SST-90


Feb 16, 2010
Orange County, CA
Recently I purchased three SST-90, three DX SST-90 drivers and Tenergy D cells.

My plan was to build a 4D DD SST-90 w/ Der Wichtels deep heatsink for the MagRebel reflector.

One problem was, I bought SR-90's, so they where on star boards. First thing I did was I took the LED off of the star with a blow torch. The solder between the star and LED melted until the LED slid off. I noticed there was a little bit of solder on the middle pad, on the bottom of the LED where it should be heatsinked. I didn't think much of it at the time. I soldered 18AWG wire to the + and -. And the used Arctic Silver epoxy to thermally mount the LED onto Der Wichtels heatsink. it was frustrating because it almost didn't fit onto the heatsink pedestal. The LED appeared to be ~.05mm to big, or the heatsink to small. So with bad jujdgement I decided to force it into the slot with vice grips :ohgeez:. Causing it to chip the corner. But it didn't appear to effect the LED's performance.

After I had the LED mounted I did some testing. I ran it with six D Tenergy cells with the DealExtreme SST-90 Driver. The batteries total where 7.5 volts. I measured 4.5 amps at the tailcap. Making the total wattage ~33 watts :devil:

But I didnt want a driver, I just wanted on/off. So I disconnected the driver and put the heatsink in a 4D Maglite with four Tenergy cells at 4.75v total. And ran the SST-90 direct drive. I soldered the LED to the Maglite switch and put a reflector on the LED. I pointed the LED at a house and it was super bright. Then it started to turn bluish, then really blue, then really really blue, then :poof:


the LED was on for less than 10 seconds before it :poof:'d. And the heatsink wasn't even warm. What happened? The voltage was