Dorcy 3D, SSC U-bin and 4 Cs WOW!

I put a SSC U-bin SWO from DX in a 3D Dorcy about a month ago and was not to impressed. It was a lot brighter then my stock unit with much brighter spill but not mind boggling. I just crammed 4 C cells into it and now it ROCKS!!!! These have a very tight hotspot and throw like a Mother! The 4 Cs are a tight fit but save a lot of weight compared to 3 Ds. I'm gonna try to shorten the spring and find some hose so I can run it on 4 rechargeable AAs. It out throws my SSC modded propoly's and Rayovac 4 watt Cree by a long shot!!!!

fishx65 said:

I put a SSC U-bin SWO from DX in a 3D Dorcy about a month ago and was not to impressed. It was a lot brighter then my stock unit with much brighter spill but not mind boggling. I just crammed 4 C cells into it and now it ROCKS!!!! These have a very tight hotspot and throw like a Mother! The 4 Cs are a tight fit but save a lot of weight compared to 3 Ds. I'm gonna try to shorten the spring and find some hose so I can run it on 4 rechargeable AAs. It out throws my SSC modded propoly's and Rayovac 4 watt Cree by a long shot!!!!

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I'm not familiar with what the circuit is in your light, maybe none at all or just a resistor. You may be really abusing the LED though, so be careful. In fact if it has much better throw than the Rayovac Cree which is already driving the Cree hard, it really does sound like you're probably heavily overdriving the LED.

Good point Triple M! Anyone know if I'm gonna kill it?

I would suspect that if you have it on very long that it's going to be harmful to the LED. If it had a great heatsink and good thermal contact to dissipate heat then it could tolerate more abuse, but I'm guessing that you're being REALLY hard on the LED. You could also damage the circuit if it has one. I haven't driven an LED hard enough to view it firsthand, but I have read many times of looking for a 'mean' blue-green from the LED when it's being heavily overdriven. I've also read that the Seoul does not hold up as well over time when overdriven compared to overdriving a Cree. If you don't already have one, you shoud buy a cheap digital multimeter and test the current being drawn from the cells to get a better idea of just how hard the LED is being driven. You could think of it as 'redlining' an engine and running at its maximum RPM, it's going to be really tough on the engine and greatly shorten its life.

yea but it's not nearly as bad as overdriving a bulb.

for instance, we over drive a 40 hour bulb with one extra cell and it becomes a 10 hour bulb.

overdrive a 100,000 hr led and... who cares.
it still will probably last for two years or so.
it greatly shortens the life but a new led is only $7

jasonsmaglites said:

yea but it's not nearly as bad as overdriving a bulb.

for instance, we over drive a 40 hour bulb with one extra cell and it becomes a 10 hour bulb.

overdrive a 100,000 hr led and... who cares.
it still will probably last for two years or so.
it greatly shortens the life but a new led is only $7

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You're oversimplifying things, aren't you? It depends entirely on just how much it's being overdriven, and from the sound of it I'm guessing that it's being overdriven a lot. I've had 5mm LEDs 'burn out' in a matter of minutes from being overdriven. The LED could be damaged to the point of reducing its output by half in just a few minutes if driven too hard, or worse. Without knowing exactly how much current is going to the LED and how well it is being heatsinked, it's hard to say how badly it's being abused, but from the description of easily out-throwing a 4W Cree known for having great throw, I'm guessing that you'll be counting the lifetime of the LED in a few hours, maybe less if used continually for extended periods of time.

fishx65 said:

Good point Triple M! Anyone know if I'm gonna kill it?

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Unless my memory is shoddy (which it probably is), the 3D dorcy has a 1.2ohm resistor between the LED & batteries. 4 NIMH AA would be 4.8volts & the resistor would probably only drop the voltage down to about 4V. Even factoring in the voltage sag, 4C at the initial 6volts would be much worse. Probably best to just run a DMM across the LED leads & see what voltage is hitting the emitter.

Personally I would swap out the resistor & fit in one of those cheap multi-mode DX/Kai drivers. But then again overdriving the seoul to super brightness is fun, isn't it?

Yep, both my 3D Dorcy has a 1.2ohm resistor in it. A quick test at the tailcap with a multimeter will tell you how much current that LED is getting since the light is direct drive.

test your current, if your high, I'd suggest a $5 fix, pick up a regulator like others have said, a 1A buck would be fine for using 4Cs, or pick up a buck/boost if you wanna go back to 3Ds.

I measured the voltage at the emitter. 3.2 volts with 3 Ds and 3.6 volts with 4 Cs. Batterys are new Alks. Is this good or bad? Think I'm gonna burn it up? Looks like heatsinking is not a problem at all with this Dorcy cuz the star sits on a huge aluminum plate. Kinda new at this modding thing but enjoying the heck out of it!

Anyone know what the max safe voltage is for a DX SSC U-Bin?

Ran the big Dorcy for about 10 hours last week while doing a little night tracking. No problems at all! We also used the Rayovac 3C Cree and I can report that the Dorcy out throws it by a very large margin. 100 yds+ was no problem. Wish I had a Tiablo or MRV to compare it to.

mmmflashlights said:

You're oversimplifying things, aren't you? It depends entirely on just how much it's being overdriven, and from the sound of it I'm guessing that it's being overdriven a lot. I've had 5mm LEDs 'burn out' in a matter of minutes from being overdriven. The LED could be damaged to the point of reducing its output by half in just a few minutes if driven too hard, or worse. Without knowing exactly how much current is going to the LED and how well it is being heatsinked, it's hard to say how badly it's being abused, but from the description of easily out-throwing a 4W Cree known for having great throw, I'm guessing that you'll be counting the lifetime of the LED in a few hours, maybe less if used continually for extended periods of time.

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no. overdriving an led reduces it's life just like a bulb.
it should still last many many more hours than an overdriven bulb, just like an led driven at the proper level outlasts a bulb driven at the proper level. you can start to lose some perfect tint halfway through the life and a little efficency too, but by the time that seoul is halfway done, there will have been five upgrades and it won't mean a thing to you.

excuse my oversimplification! hmmppfh. (sigh of indignation)

jasonsmaglites said:

no. overdriving an led reduces it's life just like a bulb.
it should still last many many more hours than an overdriven bulb, just like an led driven at the proper level outlasts a bulb driven at the proper level. you can start to lose some perfect tint halfway through the life and a little efficency too, but by the time that seoul is halfway done, there will have been five upgrades and it won't mean a thing to you.

excuse my oversimplification! hmmppfh. (sigh of indignation)

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My post wasn't a question, it was a statement. You are oversimplifying it. Like I said, it depends how much it's being overdriven, just saying that 'overdriving' will still give you a couple years on an LED is misleading, and without knowing how hard the LED is being driven and how well it is heatsinked one can't really put an accurate estimate of time on the effects it will have on the LED. If you are heavily overdriving it you could destroy an LED in a matter of minutes, or if it's very slightly overdriven it could have such a mild effect that you'd never even notice. As you said the risk to overdriving a bulb can be much riskier, but that doesn't mean that overdriving an LED can't potentially destroy it very quickly depending on how hard it's being driven. No offense intended towards you, I just don't want someone to be mislead into the thought that you can overdrive an LED hard without damaging it in a relatively short period of time, because you can, and that was my initial concern for his LED.

In any event, it doesn't sound like his LED is being overdriven much at all if it's driving it at 3.6V and he has run it for extended periods already without noticing issues.

Assuming we are talking about the old Dorcy 3D 1W torch with Luxeon emitor, I have got few questions. I have an SSC star purchased from either DX or KD a while ago. It probably is a P2/P3 bin but I am not sure. Please tell me if my deductions are correct from the following observations.

I tried to put the SSC in parallel with Luxeon. The brightness of Luxeon did not drop down much. It was difficult to judge which was brighter between the SSC and Luxeon but suffices to say, SSC was definitely NOT any significantly brighter. This tells me that if I were to replace the Luxeon with SSC, I would make this torch dimmer, NOT brighter :-(

Later, I tried to check the current via direct driving these two emitors (one at a time) via three AA NiMh cells. SSC was pulling in 0.6A but Luxeon was pulling 0.8A. Once again there was no way that SSC was brighter than Luxeon.

This tells me that the SSC has higher Vf than the Luxeon and there is no point in swapping. I would be better off just removing the resistor and driving the Luxeon as hard as I could. It is already being driven at 0.6A. With the massive heat sink, I don't see any trouble even if the current were to be doubled. Besides, if it dies, THEN I can swap in the SSC.

Any suggestions?

- Vikas

Does it mean anything that this light was probably intended for 3 alkaline D cells (4.5 V) - compared to 4 NiMH C cells (4.8 V) - not much of a difference. Or do the alkalines sag badly, so it really is a big difference?

Most of the new emitters are far more resistant to overdrive damage due to better thermal mechanics and more stable phosphors. The Rebel's and Seoul's use highly flexible dome material (not sure if there's encapsulant under there) so the diode can expand and contract without the stress and friction that a 5mm's hard plastic would induce upon the diode's structure, and the Rebel doesn't even use bond wires but is connected through the main body instead. The Cree uses a glass dome suspended over liquid encapsulant so it can move up and down perpendicularly over the diode with thermal expansion. Phosphor stability and quality has gone up over the years and guarantees better lumen and tint maintenance / endurance, even on 5mm's phosphor. LED's usually fail from massive overdriving due to tearing apart from expansion, burning up the phosphor, and/or the wires contacts being diminished or eliminated.