M6 and E2 Runtimes/Battery Voltages: Anybody Know?

carmel

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Oct 28, 2003
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OK, this newbie now has a M6, E2e, and L4 (as well as an LSH-P and LSHF-P)[what a great collection, huh?], and I have a newbie question:

Does anyone know at approximately what battery voltages the M6 and E2 drop below their rated outputs? At that point I'd like to take out the lithiums and use them in the regulated L4 and LS lights.

So, does anybody know what is the approximate voltage of the batteries when the MN20 drops below 250 lumens, the MN21 below 500 lumens, and the MN03 below 60 lumens?

Thanks!

jaws
 

js

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carmel,

123A Lithium batteries hold their voltage very well throughout their life, although they drop to 2.5 Volts under load but hold this. So you can't really tell from an open circuit voltage readout how much life is left in them. One CPFer measures closed circuit current in amps with a peak-hold DMM. He just touches the leads quickly and then disconnects. I'm not brave enough to do this, but I think he said that anything over 7 amps meant the battery was good. Do a search in that forum for details.

At any rate, the best way to tell when the batteries are approaching the end of their life, is when you start to notice a dimming of the beam. As soon as you can actually notice it, and are sure of it, change the batteries, and, yes, put the used ones in a regulated light to suck the last bit of life out of them. But taking the batteries out and measuring their voltage won't help you.
 

carmel

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Thanks, Jim!

I know that taking a voltage meter reading in the first several hours or so after use of a battery will give a false picture of the voltage remaining in a battery (at least that's my experience of alkalines). But after several hours alkalines seem to stabalize, and you can get a good picture of how depleted one is.

Do you know if this is the case with lithiums also? If it is, then somebody (maybe SF) should know what that voltage is when their lights drop under the specified lumens.

Anyway, thanks--I don't want to beat a dead horse. But it would be nice to know the morning after a night of use if the batteries should be changed before the next night of use. This sounds like an flashaholic obsessing. . . .

jaws
 

carmel

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OK, I asked my question of Surefire customer service: the answer was: "The voltage is around 2.9 when the batteries can no longer power the lamp assemblies for the incandescent bulbs." I assume that means 8.7 volts for the battery pack in the M6 and 5.8 v for the E2. Does all this sound right?

jaws /ubbthreads/images/graemlins/thinking.gif

Hey, look: I'm not a newbie anymore!! /ubbthreads/images/graemlins/tongue.gif
 

Double_A

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Math sounds right to me. I'll have to file that info from SF for reference.

GregR
 

brightnorm

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Oct 13, 2001
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Runtime/brightness comparison: PM6, P60, A2, E2


----------------CHART BY BROCK-------------------
2cell.gif



Brightnorm
 

Double_A

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Brightnorm -

Interesting chart. The A2 and E2e curves had me baffed for a second until I realized you had brightness and not lumen output.

GregR
 
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