Fried my first SST-50

[Greg G]

I hope I'm putting this in the correct forum as it pertains to running an SST-50 in direct drive on 3 NiMH's.



I *thought* this build would work.

New Mag 3 D host with deep reflector.

SST-50 on H22A heatsink machined to accept the SST emitter.

3 D size Accupower LSD batteries.

Direct drive.




After mounting the wired emitter on the heatsink I ran it on my power supply for a few minutes to make sure everything was happy. My supply only goes to 3 amps and it purred like a kitten there. Heatsink started getting hot, so I knew the emitter was dumping out heat into the heatsink.

Assuming that the the current would be somewhat higher on the batteries, but still safe, I soldered the wires to the modded switch, and install everything into the light, hit the switch, and the LED turns angry blue before I can turn the switch off.



Hit the switch again,....dead.


I don't know why I thought this would work. I guess because I've done this with several *I* bin P7's.

Anyway, don't try this at home. Direct driving an SST-5- from 3 D size NiMh's is not a good idea.


The good news is that this light modding week has not been a total loss. Last night I finished up a C2 Centurion running an SSR-50 DD off an AW 18650 (2600mah). McR27S reflector. No pill. Custom heatsink pressed into light body for star to mount to. It rocks the dock.

 

[monkeyboy]

Sounds like you were just unlucky and got a very low Vf LED. Perhaps the slightly higher voltage and lower internal resistance of the LSD cells also contributed.

I'm DDing an SST50 with 3 x titanium D 12000's and getting 4.8A hot off the charger and 3.5A (initially) if I leave the cells to cool off for a couple of hours.

 

[Greg G]

Yeah, I've read of a few people DD'ing SST-50 off C NiMH so I thought this would be fine, at least for a little while, but maybe you're right, I got a low Vf emitter.

This thing went instant blue and died before I could switch it off. I would normally suspect heatsinking, but I ran it at 3 amps on the power source for a while to make sure all that was working.

 

[420light]

Sorry to hear about your loss. :mecry:

 

[parawizard]

What are the batteries rated at :green:

 

[Greg G]

They're just 1.2 volt *nominal* D size NiMH's.

 

[parawizard]

I had a SST-90 unsolder itself from the leads! Still works good though.

 

[JohnF]

I know what you are feeling - I was starting a mod this weekend using the 6-die Ostar with a vf of 20.1v. I was testing on the bench, and set the power supply to 20v (I thought) but didn't have my reading glasses on and set it to 30v. It went from bright to blue to dark in 1 second. Damn.

John F

 

[Bimmerboy]

"Fried my first SST-50"

Does that mean you're gonna' fry another one? Hehe... ya' know, with that sigline and all...

So far, I lay claim to one dead laser diode, and a torn leg off a MC-E. Not a bad track record for being into modding for a good while now, but still, I feel your pain. :candle:

I know we get away with DD many times, but my unsolicited advice to all is to use a driver. The LED you save may be your own.

This has been a public service announcement.

 

[kengps]

I fried an SST-50 with a single 18650. What I found was that many host have a lot of resistance and thats why many get away with DD. Some big heavy wires direct to the LED will fry an SST-50 in a second or so.

 

[csshih]

I believe a sst50 gets unhappy and blue around 6A

 

[Greg G]

Does that mean you're gonna' fry another one? Hehe... ya' know, with that sigline and all...

So far, I lay claim to one dead laser diode, and a torn leg off a MC-E. Not a bad track record for being into modding for a good while now, but still, I feel your pain. :candle:

I know we get away with DD many times, but my unsolicited advice to all is to use a driver. The LED you save may be your own.

This has been a public service announcement.

It's all in the name of flashaholism.


I'm sure I'll fry lots more stuff in the future.

 

[Greg G]

I fried an SST-50 with a single 18650. What I found was that many host have a lot of resistance and thats why many get away with DD. Some big heavy wires direct to the LED will fry an SST-50 in a second or so.

Sorry to hear it.

I have a SSR-50 in a SureBlue C2 bored for a single 18650. It has a Z41 tailcap and very short 20 gauge wires running to the star. The resistance on that light has to be low. And I'm running an AW 2600mah 18650 in it, which is reputed to have less internal resistance (more amps).

It's still running thank goodness. I have no idea how many amps it is pulling though.

 

[kengps]

Sorry to hear it.

I have a SSR-50 in a SureBlue C2 bored for a single 18650. It has a Z41 tailcap and very short 20 gauge wires running to the star. The resistance on that light has to be low. And I'm running an AW 2600mah 18650 in it, which is reputed to have less internal resistance (more amps).

It's still running thank goodness. I have no idea how many amps it is pulling though.

You must have a little extra resistance in the switch then. I am able to keep it running on an 18650 IMR with about 3.5 feet of 20/22 guage wire. I am soon building a pill with a new star. Will be shortening slowly to see what it will survive on.

 

[Greg G]

There's probably not much resistance in a Z41 *twisty* tailcap. The main resistance would be in the spring, which is pretty beefy.

I am not running an IMR battery though, which could be a big difference between my light and yours.