I came across this post by paulr in What's a good light to toss in car & forget? and felt that it raised some serious issues for those of us who rely on our lithium lights. Is this specific to paulr's light, possibly due to a short, or could it be endemic to 123's and LAA's in general?
I don't have scientific backing for this but it seems to me you can't rely on the 10 year shelf life of 123's once they are already in a light and used a little. I've carried a UKE 2L in my belt pack for many years and it's great. It seems to me that I've had to change the batteries after just a few minutes of total runtime though, because the runtime is spread out over possibly a couple of years. It's like putting new cells into the flashlight and using it on for a few minutes starts some kind of reaction going in the cells, that doesn't stop after you turn off the light, so they have some self-discharge. So I've put new cells into the light, used it a few times (hardly ever for more than a minute or so), and then found the batteries were dead.
So, if you're going to put a 2L (or any other light for that matter) in your car to "forget about", putting some spare batteries alongside it is also highly adviseable.
Well, I recall somewhere I read that you can never rely on the shelf life property of any battery as advertised after you use it, even slightly. I agree with Paulr. Dunno if it because of the reaction, but certainly not because short. The same applies to button cells, where the manufacturer/ advertiser said that its shelf life is forever. However, it also added that this shelf life only applies when the batteries is fresh in the package.
Uh, from close to twenty years ago when MicroTec(?) came out with a Lithium flashlight that used a 3V double-long-AAA-like battery, the datasheet that came with the battery discussed the ten year shelf life as being due to a "skin" forming on one of the internal chemical elements of the battery that prevented self-discharge. The "skin" would be breached when the battery was used, and might eventually grow back with extended non-use, but that it was not guaranteed.
The same applied to the lithium batteries used in the ELT's we had in out aircraft: So long as they haven't been used they were good for a long time, once use had started they would self discharge if use was interrupted.
Sounds like what y'all are experiencing.
I haven't seen anything "new" on this effect - by that I mean haven't seen this mentioned recently in lithium battery info ...
Well, this is unpleasant news indeed. I never saw this discussed in CPF probably because most people assumed as I did, that "shelf life" held relatively constant regardless of use. I guess I'll be changing my lithiums much more frequently from now on.
Does anyone know the self-discharge rate of lithiums after first use?
Haven't heard anything but the solutiuon is simple.
If you're reading this you're a flashaholic and will likely, at some point in your life, have 2 Lithium lights. If Light "A" is used every day and "B" is a backup, put fresh batteries in "B." Soon after "B" is used (Not the minute after, you could probably go months and be ok) rotate fresh batteries in "B" and put the old batteries in que to be used in "A"
[ QUOTE ] Saaby said:
Haven't heard anything but the solutiuon is simple.
If you're reading this you're a flashaholic and will likely, at some point in your life, have 2 Lithium lights. If Light "A" is used every day and "B" is a backup, put fresh batteries in "B." Soon after "B" is used (Not the minute after, you could probably go months and be ok) rotate fresh batteries in "B" and put the old batteries in que to be used in "A"
[/ QUOTE ]
Good idea. I'm tempted to do a long term test: Burn two new 123's for three minutes in a 6P, then check voltage, put them aside and test voltage at least once a week for a year,
keeping a record of readings.
You've got do an actual runtime test, like run the light for 2 minutes once a month for 5 years. 1 year isn't enough to really see the effect we're talking about.
Saaby is correct,I have found that after use in my uke2l that "shelf" life of new lithiums dwindles to between 6-9 months in my vehicles environment.And runtime,afterwards is about a quarter of new,unused lithiums.In my case,I will rotate the batteries between other lithium powered lights,and insert new batteries in the car flashlights.I have also learned the hard way,as usual,not to store the batteries in the factory package.The cardboard absorbs the high humidity,further still degrading storage life.
I haven't really noticed this, but I do swap out my batteries. When they run dead in my A2, I pull them from one of the car's UKE2L and put fresh ones in there. I guess that’s why I never noticed it before. I also am actually using my batteries until they are dead now with the help of the A2 so I don't have as many sitting around.
New concerns about lithium life
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