Do you keep your batteries in your multiple cell Li-Ion lights?

Guitar Guy

Enlightened
Joined
Oct 23, 2016
Messages
590
Location
West Virginia
I did find some old threads with some folks detailing how they checked for parasitic drain with removing the tail cap and testing with an ammeter, but I'm not really going to get into all of that.
 

letschat7

Flashlight Enthusiast
Joined
Dec 7, 2022
Messages
2,486
Location
West Virginia, North America
@letschat7, that looks pretty nasty, but 20 years is a pretty long time. I think my oldest Li-ion cells are about 7 yrs old. I've only ever had one fail, and it just pretty much went dead all of a sudden. I think the protection circuit may have failed. There was no venting or event. When I tested it, nothing registered at all, so I got rid of it. I believe it was a Nitecore 18650. All of my Li-ion batteries are protected Fenix & Nitecore, and a few Acebeam & Imalents that came with the lights. Most of them have not really been charged very many times.
I bought it thinking it was usable went to charge it and was like fuuuuuuuuuu.
 

PaladinNO

Enlightened
Joined
Jun 22, 2017
Messages
244
Location
Norway
I keep all my lights loaded, but I equally keep the cap slightly unscrewed on all of them to prevent any parsitic drain, which most of my lights unfortunately have. And I do it on everything from my single-cell to the dodeca-cell (12-cell) lights.
 

vicv

Flashlight Enthusiast
Joined
Mar 22, 2013
Messages
2,936
Location
Southern Ontario
What exactly is the fear here leaving cells in lights in series specifically?
Is it worse to you than a single cell? Why?
As far as parasitic drain, why is it a worse issue in a multi cell light?
And on parasitic drain, if your light has an electronic switch, it has it. If it's a mechanical switch, it doesn't
 

Guitar Guy

Enlightened
Joined
Oct 23, 2016
Messages
590
Location
West Virginia
What exactly is the fear here leaving cells in lights in series specifically?
Is it worse to you than a single cell? Why?
As far as parasitic drain, why is it a worse issue in a multi cell light?
And on parasitic drain, if your light has an electronic switch, it has it. If it's a mechanical switch, it doesn't

This thread is a couple of months old, and my question pretty much got answered.

The reason for the question about multi cell lights was regarding if a light sat around for 6 months or a year without getting used, could there be a danger of one cell failing or rapidly discharging way more than the other(s), and would it cause the other cell(s) to try to charge the failing one, and somehow cause a safety hazard. If that were the case, I had wondered if it would be safer to remove cells from lights that seldom get used.
 

vicv

Flashlight Enthusiast
Joined
Mar 22, 2013
Messages
2,936
Location
Southern Ontario
Ah. Ok. Already answered then but ya, no issues. One cell cannot charge another one when they are in series, so no issue there. And if there is no parasitic drain, also, no issue. But in my opinion, if you were going to leave a light, unused for that long, I would take the cells out. Only so I can put a storage charge on them so they will not degrade.
 

PaladinNO

Enlightened
Joined
Jun 22, 2017
Messages
244
Location
Norway
My bad, sorry. Didn't mean to necro anything, this thread just showed up in the "similar thread"-feed, and I misread the month.
 

Monocrom

Flashaholic
Joined
Aug 27, 2006
Messages
20,175
Location
NYC
Honestly, sitting around for 6 months to a year unused; grab your charger and top off those rechargeable cells before using the light.
 

Guitar Guy

Enlightened
Joined
Oct 23, 2016
Messages
590
Location
West Virginia
Honestly, sitting around for 6 months to a year unused; grab your charger and top off those rechargeable cells before using the light.
Yes, I do, but most of them do get used a little here and there. It's just that I have a lot of lights, so I try to use most of them a little in order to keep cycling the batteries, but it takes quite a while before they actually "need" to be charged.
 
Top