CMG Reactor 3 and Lithiums?

[epro05]

I know CMG warns against using Lithium AA's in the Reactor 3, but I was wondering if any brave souls have tried them anyway.

If so, what has been your experience regarding brightness, burn time, or damage to the Luxeon Star?

Phil

 

[Azreal911]

wouldn`t that fry the luxeon with the huge dosage of amps it will get? cause i thought the reactor 3 is direct driven.

 

[epro05]

I've read in this forum that the Reactor 3 has a 2.2 ohm resistor. Assuming 4.5 volts, 3.42 Vf, and 2.2 ohms, the current would be about 490 mA. I know that's considerably above the 350 mA that the part is spec'd at, but from what I've read on this board, almost all the LED lights are overdriven, considerably.

Phil

 

[Quickbeam]

Heatsinking is the problem. The overdriven Luxeons you read about here are heatsinked to the metal body of the lights they reside in (if they're made properly). The CMG head is plastic, which insulates rather than conducts heat, so it would get very hot inside the head and cause thermal damage to the Luxeon - initially reducing its efficiency, eventually causing failure.

 

[Ray_of_Light]

The Reactor 3AA I have has a 2.4 ohm resistor in the tailcap, and draws 350 mA from 3 AA batteries (4.5 Volts).
The resistor is a quarter watt, overheating.
The Luxeon is not well heatsinked, being encased in the plastic head.
With new lithiums AA, the current flow is abouth 500 mA, overdriving a underdissipated Luxeon, an frying the limiting resistor in the tailcap.
I suggest not, nor they do.

Anthony

 

[FalconFX]

You can direct drive the Reactor III with the tailcap from the original Reactor, but the RIII is resistored... Even at that, Lithiums aren't recommended...

 

[epro05]

Thanks for the information. I'll stay away from the lithiums for sure. The design margin just isn't there for heatsinking.

By the way, the UPS guy just delivered my Reactor 3 a few minutes ago, so I took it out into my garage (dark there) and tried it out. I like it and the beam quality is pretty good, not excessively green.

I also bought an Inova X5T earlier this week. The Reactor is significantly brighter than the X5T but the smaller light fits the pocket better and its brightness and beam smoothness was quite good also.

What got me started on all this is that my brother gave me a Pelican L1 about two weeks ago and that woke me up to how much better the beam quality can be compared to everything else I had used in the past. After some websurfing I discovered CPF and the information here has been great and very helpful.

I've got a Streamlight Scorpion coming tomorrow, for when I need more throw and brightness.

So, with a Pelican L1, Inova X5T, Reactor 3, and a Scorpion, I think most of my needs will be met.

Phil

 

[The_LED_Museum]

[ QUOTE ]
TheProphet said:
With new lithiums AA, the current flow is abouth 500 mA, overdriving a underdissipated Luxeon, an frying the limiting resistor in the tailcap.

[/ QUOTE ]

If you let all the magic smoke out of that resistor, nothing will work anymore. The resistor won't resist, and the Luxeon won't lux. /ubbthreads/images/graemlins/icon15.gif
At this point, you get all pissed and either throw the Reactor in the toliet, or replace that resistor. /ubbthreads/images/graemlins/eek.gif

I'm pretty sure it says "Do not use lithium batteries in the Reactor 3" for a reason. /ubbthreads/images/graemlins/wink.gif

 

[epro05]

The LED Museum,

I'm convinced at this point and appreciate the advice. I will not be using Lithiums in my Reactor 3. I just got it today, and I'm happy with the brightness and throw. I'm also happy with it's beam color and I just posted a few pics comparing it to my Inova X5T and Pelican L1.

I have a Scorpion on the way that I hope will satisfy my quest for a few more lumens, for those times that it's really needed.

Everyone has been so helpful with my question. Thanks so much.

Phil

 

[stangster]

I took off the little circuit board w/ resistor and the plastic thing, stuck in a large spring and put the tailcap back on.

I don't see one bit of difference in brightness.

Plus, I left it on for 15 minutes w/o any noticeable heat radiating from the head. This is the same with the board back in place as well.

What gives? Where's the extra "umph" that everyone talks about?