Cr123a cutting out

vicv

Flashlight Enthusiast
Joined
Mar 22, 2013
Messages
1,387
Location
Southern Ontario
I am somewhat new to using primary lithium cells in incandescent flashlights. So I was wondering if anyone has seen this behaviour before. I have three of them in a mag light ML 25IT in a reducer and a 7.2 V 1.2 amp Bulb. They have been working very well up until this morning when I want to use this light for some thing and it didn’t work. No light at all. I remove the batteries and installed 2 18500s and it worked fine so it was not the bulb. I tried three fresh primary cells and it worked fine. Put the old ones back in and no light. So these three are only not working in this one flashlight but they work in anything else and anything else also works in this flashlight. These are good Panasonic cells. I don’t imagine that they just feel like this when at a lower voltage as tactical lights used them so this is odd behavior. Anyone have experience like this? I’d do not have another light I can put these i these are good Panasonic cells. I don’t imagine that they just feel like this when at a lower voltage as tactical lights used them so this is odd behavior. Anyone have experience like this?
They all measure 2.75v under load. But swapping between them and I did discover that one of them cannot provide good brightness from an LED light. So One is dropping significantly under load compared to the other two. But are used the light last night and it was still quite bright so this happened just sitting there overnight. But it obviously was not accidental left on as two of the three batteries can power in LED light at 1.4 A with what appears to be full brightness
 
Last edited:

Lynx_Arc

Flashaholic
Joined
Oct 1, 2004
Messages
10,833
Location
Tulsa,OK
Try this advice (be careful)
 

vicv

Flashlight Enthusiast
Joined
Mar 22, 2013
Messages
1,387
Location
Southern Ontario
Going to a dead short on my meter doesn't seem fun.
I understand stand that one of the three is dead. I expected them to discharge equally. That being said, I'm more concerned that it will not light the lamp at all. But the bad one and a working one will light a 7135 based light. Won't go past 30 or so lumens but will light.
It's like in the incan lights, it's just a broken connection
 

Lynx_Arc

Flashaholic
Joined
Oct 1, 2004
Messages
10,833
Location
Tulsa,OK
Could it be the PTC?
I don't use CR123s but likely the load you are putting on it via your testing isn't nearly as much as the load the light puts on it and that heavier load on one or more cells is causing it to cave in voltage too low to be useful. I once had a remote with some maganese type batteries of some odd sort that came with the remote and the remote started acting up I tested the batteries with a voltmeter (no load) and it measured 1.6v but kept cutting out in a remote. I put half depleted alkalines in it and it worked perfectly. I've used the testing procedure listed in that thread what you do is take meter with a shunt in it (10-20A separate circuit) that has a second hole for the leads and essentially short the cell across the shunt and measure the current very quickly just touching long enough to get a reading. Compare that with the other cells and some newer ones to see what you get. You may see currents like 7A or more not sure as I've only done this with nimh batteries. Don't do this a lot as it does drain batteries if you do too much of time this way.
 

vicv

Flashlight Enthusiast
Joined
Mar 22, 2013
Messages
1,387
Location
Southern Ontario
I don't use CR123s but likely the load you are putting on it via your testing isn't nearly as much as the load the light puts on it and that heavier load on one or more cells is causing it to cave in voltage too low to be useful. I once had a remote with some maganese type batteries of some odd sort that came with the remote and the remote started acting up I tested the batteries with a voltmeter (no load) and it measured 1.6v but kept cutting out in a remote. I put half depleted alkalines in it and it worked perfectly. I've used the testing procedure listed in that thread what you do is take meter with a shunt in it (10-20A separate circuit) that has a second hole for the leads and essentially short the cell across the shunt and measure the current very quickly just touching long enough to get a reading. Compare that with the other cells and some newer ones to see what you get. You may see currents like 7A or more not sure as I've only done this with nimh batteries. Don't do this a lot as it does drain batteries if you do too much of time this way.
That I could see as with the convoy s2+, clicking past low mode doesn't get any brighter. Just strange as even dead alkalines will show a very dim output but not nothing. And last time I used the light it was fine. Just yesterday. Not full brightness but still pretty good. Like maglite kypton bulb on fresh alkaline CCT
 

xxo

Flashlight Enthusiast
Joined
Apr 30, 2015
Messages
2,467
The bad cell might be causing the other cell's PTC's to throttle current. Try the bad cell in a one cell light and compare it to the others,. If you don't have a one cell light, try it with a 2 cell bulb in your ML25IT.
 

vicv

Flashlight Enthusiast
Joined
Mar 22, 2013
Messages
1,387
Location
Southern Ontario
Ya I dont currently have a 1 cell light. I'm not sure how I'd make am electrical connection with a single cell in my ml25. I don't have dummy cr123 cells. It's not a big deal. Also I've already dropped it off in a battery recycle bin since clearly it was dead. I presume this is just the way this chemistry of battery goes once it's dead and I had one that even new died faster than the others. I was just surprised by the abrupt "failure"
 

xxo

Flashlight Enthusiast
Joined
Apr 30, 2015
Messages
2,467
Inconsistent cells are rare, unless they are made in China or are fake USA cells - this has caused exposions in multicell lights as the Chinese/fake cells often lack functional PTC's. There have been warnings about this circulated among law enforcement.
 

vicv

Flashlight Enthusiast
Joined
Mar 22, 2013
Messages
1,387
Location
Southern Ontario
Ya. These are genuine Panasonic cells
PXL_20211021_203739220.jpg
PXL_20211021_203746160.jpg
 

xxo

Flashlight Enthusiast
Joined
Apr 30, 2015
Messages
2,467
You should be able to see a sliver of the green PTC peeking out under the wrapper on the base of the cell.
 

xxo

Flashlight Enthusiast
Joined
Apr 30, 2015
Messages
2,467
That's it. Apparantly all USA made CR123A's are made by Panasonic which uses a green PTC.
 
Top