SF A2 Question

[Bravo25]

I have an A2 that has started dropping the incan to 1/2 brightness. Not all the time, but at least half the time. I can push the button or screw the tailcap down, the leds light up, and the incan comes on about half way. Releasing,and depressing the cap again, or loosening, and then tigtening the cap again can cause it to come to full brightness. Repeating the above steps might cause it to be dim again, or full bright.

Is there a low voltage threshold that the light will drop out of regulation, and cause this behavior?

 

[Hoghead]

It sounds like you need to clean the threads on the body and the switch.

 

[FlashlightOCD]

When the batteries are nearly shot, the light will sometimes exhibit this type behaviour. Try some fresh batteries and see if it fixes the problem.

 

[Bravo25]

It was the batteries. I have run 2 sets through this light now. The first were Surefires, and once they were depleted enough the incan ceased to work at all, and I just got the LED's. The second set was an off brand import, and they didn't seem to "cut off" the way the SF's did.

 

[FlashlightOCD]

Just a FYI, the same thing can happen with SF batteries too. It is just a function of how the batteries behave at the end of their lifespan.

 

[CM]

Bravo25,

Can you take the spent batteries and try it out in another light, preferably an L4 if you have one and see if it powers it at full brightness. I'm curious as to how much power is left when the A2 goes out of regulation.

Thanks,

CM

 

[Bravo25]

[ QUOTE ]
CM said:
Bravo25,

Can you take the spent batteries and try it out in another light, preferably an L4 if you have one and see if it powers it at full brightness. I'm curious as to how much power is left when the A2 goes out of regulation.

Thanks,

CM

[/ QUOTE ]

I can.
I did.
It does.
Although I don't know for how long without doing a run time test on it. I don't like doing these on my personal lights, so I will try to guestimate it for you as I use it.

I will also check voltages tonight. I don't have a test circuit setup, so I can't advise as to amps.

 

[CM]

Bravo,

Thanks, don't do a runtime test as I can probably guess pretty good. I just wanted to confirm my suspicions and you did it for me. It's too bad that extra power could not be used to keep the A2 in regulation for a bit longer. I guess surefire decided that at that point, the LED's should get you out of a bind if you really needed the light.

 

[Bravo25]

I did use the L4 for a while last night, and it ran about 5 minutes total at full brightness, then dropped to low output. The voltage (although this is discussed as an exercise of futility) ran about 2.5 volts. I need to find a way to use up these batteries, as I don't care to have my KL1, or KL4 running on used up batteries needlesly.

 

[this_is_nascar]

If you had 2.5 volts left, that enough to power-up an Arc4.

 

[flashboy]

put those mostly used up batteries into an INOVA X5. That will use them up the rest of the way and make a lot of light doing so.

 

[CM]

I use the Arc4+ with "dead" 123's as a nightlight sometimes. Arc4 is great for totally finishing off 123's from other flashlights, including the Arc LS series. I can get many many hours on dim in the Arc4+. I think the Arc4 will get the best use from dead 123's--I'd say much better than ANY other light.

Bravo,

Thanks for the results. I guess there's still plenty of life left in the 123's to use in the Arc4+ since the KL4 is really a current hog. 5 minutes is a lot when the thing is drawing probably over 1.4A at that depleted voltage level.

 

[chamenos]

another good light for finishing up used batteries is the pelican M6 LED. i'm running it on a couple of bottles of spent lithium batteries at the moment. it makes an excellent utility or around-the-house light /ubbthreads/images/graemlins/grin.gif

 

[symes]

Amen on the X5 - seems to suck 123s totally dry!

 

[MoonRise]

Arc 4+ and \'dead\' 123s (was)Re: SF A2 Question

Yeah, the Arc 4+ works with pretty dead 123s. /ubbthreads/images/graemlins/thumbsup.gif

I grabbed a 'dead' 123 (I measured 0.8V through a 4.7 ohm load, that's pretty dead! /ubbthreads/images/graemlins/tongue.gif). I popped it into the Arc 4+, waited a few seconds for the light to boot-up and then turned it on. I was able to get Level-16 and up to IIRC Level-12 or so.

The Arc 4+ /ubbthreads/images/graemlins/buttrock.gif

 

[this_is_nascar]

Re: Arc 4+ and \'dead\' 123s (was)Re: SF A2 Question

[ QUOTE ]
MoonRise said:
Yeah, the Arc 4+ works with pretty dead 123s. /ubbthreads/images/graemlins/thumbsup.gif

I grabbed a 'dead' 123 (I measured 0.8V through a 4.7 ohm load, that's pretty dead! /ubbthreads/images/graemlins/tongue.gif). I popped it into the Arc 4+, waited a few seconds for the light to boot-up and then turned it on. I was able to get Level-16 and up to IIRC Level-12 or so.

The Arc 4+ /ubbthreads/images/graemlins/buttrock.gif

[/ QUOTE ]

I don't understand. I had thought the Arc4 needed 2.0 volts to ignite.

 

[milkyspit]

Re: Arc 4+ and \'dead\' 123s (was)Re: SF A2 Question

Based on my mathematical fiddlings, that 0.8V through a 4.7 ohm load suggests 170mA current flow. That would seem to be enough to convert into something useful for a Luxeon, though it would be pretty dim! Note that the 0.8V is under loaded conditions... with the battery unhooked it might show something much higher, like perhaps 2.7V. Dying 123 cells sag quite a bit in voltage under load.

 

[The_LED_Museum]

Just resetting the subject line to match what this thread started off as. /ubbthreads/images/graemlins/wink.gif

 

[MoonRise]

Re: Arc 4+ and \'dead\' 123s (was)Re: SF A2 Question

The 0.8V was with a 4.7 ohm load. No load voltage was 2.6-2.8V or so.

It has gotten to the point now where if I'm going to use the Arc 4+ on the lower levels for a while and I'm anywhere near the 'dead' cells, I'll swap out the good cell for one of the 'dead' ones. When I'm done, I just put a fresh 123 back in for general EDC. /ubbthreads/images/graemlins/grin.gif

The Arc 4+ /ubbthreads/images/graemlins/buttrock.gif