SST-90: My first modded light- Update

[gt40]

I just poofed my sst90 top bin with 4 cta c nimh batteries.

This was my first modified light. It was in a 3d mag with 2" custom copper heatsink, cutdown spring, direct driven . It ran really really bright for about 3 minutes then went dark. I didn't get a chance to measure volts to the led or amps or get any pics. I was so excited I finally got the thing to work I ran out from the garage to the back yard to enjoy my first build.

I saw a couple of other posts where SST-90's were run on 4 c nimh batteries and they were fine. I guess I am still learning. I am wondering if I used too big gauge wire(18 gauge) and the voltage was still two high. 4x 1.3 volts (measured the cta batteries after full charge on the cheap eveready charger) = 5.2 less any resistance from the body and connections.

I will post some pics but I came up with an easy way to make the heat sink using an old copper ribbon coil I had laying around and some aluminum pipe. Basically I rolled the copper ribbon till it was the inside diameter of the tube and then stuck it in. I heated the whole thing with a map torch and put solder on the ends and ground it flush. Finally I drilled a hole the diameter of the stock mag switch on the appropriate spot on the tubing.

I have ordered another sst90 but don't want to kill another one so any suggestions would be appreciated.

 

[Ajay]

Re: SST-90: My first modded light- need help!

I will post some pics but I came up with an easy way to make the heat sink using an old copper ribbon coil I had laying around and some aluminum pipe. Basically I rolled the copper ribbon till it was the inside diameter of the tube and then stuck it in. I heated the whole thing with a map torch and put solder on the ends and ground it flush. Finally I drilled a hole the diameter of the stock mag switch on the appropriate spot on the tubing.
.

Oh my....I gotta see some pics of that build. Very interesting.

Sorry about your mishap. What is cta? NIMH cells can give a good amount of juice and there is a chance it was over driven. Next time measure the current flowing to the LED when you power up for the first time just to make sure it wasn't too much current that blew it up.

Next make sure it doesn't over heat.


Ajay:welcome:


EDIT: 4 cells!!?? Vf for the SST 90 is 3.1 to 3.6 but I guess with voltage drop 4 cells are ok.....I will let a CPF elder comment on this further.

 

[gt40]

Re: SST-90: My first modded light- need help!

Ajay wrote:

What is cta?

I got them at a local electronics parts store in LA. They seem to be the baby cousins of the 12000 mah D cells the company makes:
http://www.google.com/products/cata...ct=result&resnum=3&ved=0CBcQ8wIwAg#ps-sellers

 

[ma_sha1]

Re: SST-90: My first modded light- need help!

Probably due to inadequate heat transfer,
next time use SSR-90, the one on star.
A lot easier for heat transfer

I just poofed my sst90 top bin with 4 cta c nimh batteries.

This was my first modified light. It was in a 3d mag with 2" custom copper heatsink, cutdown spring, direct driven . It ran really really bright for about 3 minutes then went dark. I didn't get a chance to measure volts to the led or amps or get any pics. I was so excited I finally got the thing to work I ran out from the garage to the back yard to enjoy my first build.

I saw a couple of other posts where SST-90's were run on 4 c nimh batteries and they were fine. I guess I am still learning. I am wondering if I used too big gauge wire(18 gauge) and the voltage was still two high. 4x 1.3 volts (measured the cta batteries after full charge on the cheap eveready charger) = 5.2 less any resistance from the body and connections.

I will post some pics but I came up with an easy way to make the heat sink using an old copper ribbon coil I had laying around and some aluminum pipe. Basically I rolled the copper ribbon till it was the inside diameter of the tube and then stuck it in. I heated the whole thing with a map torch and put solder on the ends and ground it flush. Finally I drilled a hole the diameter of the stock mag switch on the appropriate spot on the tubing.

I have ordered another sst90 but don't want to kill another one so any suggestions would be appreciated.

 

[gt40]

Re: SST-90: My first modded light- need help!

ma_sha1 wrote:

Probably due to inadequate heat transfer,
next time use SSR-90, the one on star.
A lot easier for heat transfer

Sorry if I missposted. I am still new to led's and ssr vs sst. I got this one: SSR-90-W65S-R11-GN100. It was on a star. It was glued with artic silver on a 2 1/2" x 1 3/8" copper heat sink with aluminum shell. I don't know how I could have fit a bigger heat sink in there....

 

[overdog]

Re: SST-90: My first modded light- need help!

(ups GT40, you posted faster...and you used an SSR?)
I think ma_sha1 is right, it´s much safer to use SSR´s because of better heat transfer- SST´s are only glued with half of the downside to the heatsink, rest is used for connecting wires, no way to transfer heat as good as the SSR´s - When I used SST´s for example in my 4AA 1D I could realize, that after some runtime the optics of the dome of the emitter changed, the shadow at the border of the beam was wandering...hard for me to explain in english, I think it had to do with growing heat which changed the optics of the dome... I dont have such problems even after longer runtime with my Mag 4D where I use SSR.

Those LEDs are still new, we can just collect our experiences we made to find out, how to power them in the right way...

 

[overdog]

Re: SST-90: My first modded light- need help!

Hello gt40,
I have a question, did you use the original mag switch?

 

[gt40]

Re: SST-90: My first modded light- need help!

Hello gt40,
I have a question, did you use the original mag switch?

Yes i did. battery to switch to led with the negative grounded on the heat sink which completes the loop with the tail through the body.

 

[SFG2Lman]

Re: SST-90: My first modded light- need help!

sounds like just too much voltage, voltage drop happens to smaller batteries under heavy load, but from what i understand you have some serious batteries...try 3 cells, that'll put you at 3.9, be easier for that LED to swallow, that is if you still want to direct drive it, otherwise get a Constant current driver, if direct drive is still a favorite though, either chop the length of your battery tube and rethread it for the tailcap, or use a dummy cell

 

[overdog]

Re: SST-90: My first modded light- need help!

Are you sure your emitter is dead? Check your switch, as much as I know original mag switch is not able to handle higher amperage like something around 9 -11Ah you may got with freshly charged batteries- I modified my switch, in short words: each electricity leading part inside the switch which seemed to be to thin to handle higher amperage I thikened with solder for example...

 

[gt40]

Re: SST-90: My first modded light- need help!

Are you sure your emitter is dead? Check your switch, as much as I know original mag switch is not able to handle higher amperage like something around 9 -11Ah you may got with freshly charged batteries- I modified my switch, in short words: each electricity leading part inside the switch which seemed to be to thin to handle higher amperage I thikened with solder for example...

Thanks for the feedback. I just got home from work and checked things out a bit more. I hooked up an imr 18650 with to wires directly to the pos and neg terminals of the led and got nothing accept a little "crackle" sound and no joy. It is definitely dead. I also measured the voltage with my meter with the leads touching the positive wire connected to the now dead led and the neg touching a bit of the bare aluminum i could see by slightly unscrewing the tail. 5.2 volts

 

[jasonck08]

Re: SST-90: My first modded light- need help!

Any pictures of the build... Sorry that you it sounds like you fried the LED.

Some people are successful with driving it with 4x Ni-mh's, but it all depends on the voltage sag of the cells. It's best to check the amperage, and the voltage at the LED before "playing" with your new light...

If they are higher end cells that don't have much voltage sag, then your going to be better off running 3 cells. If the voltage drops a lot then you might need to run 4 cells.

 

[overdog]

Re: SST-90: My first modded light- need help!

It´s the led, but now I am interested in, what amperage an original mag switch can handle, any experiences with? Did you check the inner of your switch, anything like melted plastics or something like this to see? To me some parts inside the switch look, as if they can handle lot of power (ring in the middle), some other parts like the small plates who make contact to the ring in the middle do not seem to be able to handle higher amperage compared to some 10Ah/24V switches I have at home... I never tried a Mag switch without modding a little bit in my SST-90 lights- could be the next problem you could get when you put in your next emitter...

 

[gt40]

Re: SST-90: My first modded light- need help!

Thanks for the feedback, I think the problem was just too much voltage to the emitter. I am making a new heatsink design and going to start a new thread to detail the build.

Link to build thread is here: http://www.candlepowerforums.com/vb/showthread.php?t=253367