FourSevens Mini123 HCRI voltage cutoff issue?

cland72

Flashlight Enthusiast
Joined
Nov 23, 2009
Messages
3,276
Hi all,

My 47 Mini123 HCRI wouldn't get brighter than the initial mode (low) last night when I went to turn it on. I rarely use this light, and when I checked the battery voltage, it was 2.88v resting. Shouldn't the mini operate in regulation down to 0.9v?
 

Hondo

Flashlight Enthusiast
Joined
Oct 26, 2005
Messages
1,544
Location
SE Michigan
The resting voltage may be high enough, but that cell could be so dead that it can't deliver any current. The voltage will just sag and almost no power comes out when loaded.
 

Hondo

Flashlight Enthusiast
Joined
Oct 26, 2005
Messages
1,544
Location
SE Michigan
Well indeed it is, happy 1000 to me! :party:

Let's make it a good one.

Since you can not judge the capacity of a CR123 from resting voltage, this is what I do to gauge them with a DMM. It's called a "flash amp" test. Set your meter to measure current, on the 10 Amp scale. Low current meters won't work. Then connect the leads right across the battery, for only one second. Read the meter while it is connected. If it goes up to 8-10 Amps, it's a fresh cell. If it is only 3-4 Amps or less, it's about had it, but may work for a while on low modes only. It may seem a bit hard on the cell to do this, but it is OK for one second and gives a real good reading of cell capacity.
 

cland72

Flashlight Enthusiast
Joined
Nov 23, 2009
Messages
3,276
Hondo, I did your test and got 0.24 amps max. I guess it is a dead cell after all. Thanks for the input!
 

cland72

Flashlight Enthusiast
Joined
Nov 23, 2009
Messages
3,276
I know I'm bumping an old thread, but there's something new to note that is relevant to this discussion: a battery that would not power my mini AT ALL was removed and put into my Surefire E1B. It powered the E1B on low just fine without any issues.

Strange... I guess either the E1B has a bad *** boost driver, or the Quark voltage range is overstated... Thoughts?

edited to add: the resting voltage of the primary was 2.77 volts.
 
Last edited:

archimedes

Flashaholic
Joined
Nov 12, 2010
Messages
15,780
Location
CONUS, top left
Although I wouldn't call it a "battery vampire" , my E1B will run on low with cells that are too empty to power many other flashlights.
 

Hondo

Flashlight Enthusiast
Joined
Oct 26, 2005
Messages
1,544
Location
SE Michigan
Sounds like the E1B is pretty close to a battery vampire. Wonder how long it can keep it running with that cell. And if the other cell that ran the Mini on low only flash amped at 0.24 A, how low would this cell be?? I don't consider that a loss for the Mini, just an uber-win for the E1B.
 

sidecross

Flashlight Enthusiast
Joined
Jul 29, 2012
Messages
1,369
I might be over cautious but the main reason I bought a load battery tester was to check voltage to make sure primary 123 batteries in series were matched. I bought the tester a few years back and think it is still a good investment with all my flashlights and batteries.
 

sidecross

Flashlight Enthusiast
Joined
Jul 29, 2012
Messages
1,369
The cells we are discussing would be unlikely to activate even the lowest indicator on a ZTS ....
And that would indicate the battery under load is less than 10% and for me it would be useful information. :wave:
 
Top