"Sudden Death" Problems with Energizer Ultimate Lithium

[rgarito]

Not only is this annoying (and costly over time), but it's bugging me from an engineering standpoint:

I searched on this forum and found a discussion about this exact topic a few years ago but it was never really resolved/answered.
I also see the same topic on a few flashlight web forums and the same thing there--many people reported the issue but nobody seems to have figured it out...  (see here for one of several threads on the topic:  https://www.candlepowerforums.com/threads/battery-station-lithium-aa-sudden-death-again.107892/  )  I'm also seeing complaints of the same on Amazon's reviews.  So....

I have been noticing that when I use Energizer Ultimate Lithium batteries in series, after a few weeks of light use (max, sometimes it happens in a day), one of the batteries will go completely dead--no voltage at all--while the others read fine.  Replace the bad cell and the problem repeats in a few days. 

I've seen this in multiple devices, generally low current draw (remote controls, non-rechargeable battery backups for a weather radio that is normally mains powered, etc).  I use these batteries mostly because they don't leak like DuraLeak cells do...

Some on the flashlight forum were speculating that this was caused by some sort of weird failure mode triggered by being in series.  One thing I noted on Energizer's datasheet ( https://data.energizer.com/pdfs/lithiuml91l92_appman.pdf ) they mention that there is a PTC (self-resetting fuse) in the positive lead for safety.  Could a series connection somehow be burning these PTC's out?

Ideas?  Dave--you should run some tests in a video!

[bdunham7]

I have been noticing that when I use Energizer Ultimate Lithium batteries in series, after a few weeks of light use (max, sometimes it happens in a day), one of the batteries will go completely dead--no voltage at all--while the others read fine.  Replace the bad cell and the problem repeats in a few days.

I not convinced as to how good these are for devices with a continuous high drain.  However, this is not an unknown issue with batteries with flat discharge curves used in series.  What happens is that at the end of their life, the voltage drops off rapidly and if the remaining cells still have life, they force current through the expired cell causing it to be charged in reverse polarity.  So if you replace just that cell, then another cell will be the one to run out of juice and the same thing happens again.  I'm presuming that when you say the problem repeats, you don't mean that the cell you just replaced has gone bad--if so there is something else wrong.  So always put in all new cells in a series application and replace them all when one dies. 

[rgarito]

Most of the time that I paid attention, it was a different failing cell each time (different position within the series string). 

I have witnessed the weird "reverse polarity" alkaline battery issue on devices over the years a few times (where the battery reads reverse polarity).  But not on these devices.

One place I've seen it is a simple remote control  (twice so far in the same remote), where there is no power draw except when a button is pushed.  Yet one cell died completely a few days after being inserted.  I can't see how that could happen being there is no complete circuit when it's sitting there doing nothing (not a circuit that would have a CPU running in some sort of low power mode). 

The people in the attached thread above on the other forum are referring to flashlights.  So when it's off, it's off.  Makes no sense whatsoever.  I'm considering taking one apart (carefully) once it fails and checking the PTC and seeing if there is anything else obvious going on.

Some are speculating that the physical construction is causing the connection to break internally due to spring pressure, even.

These batteries are considerably more expensive than alkaline, so it gets expensive when this keeps happening.

[edpalmer42]

Some are speculating that the physical construction is causing the connection to break internally due to spring pressure, even.

I haven't seen this problem, but I don't think it could be caused by the physical construction.  Such a failure mode would result in batteries that were dead in the package and that doesn't seem to be the case.

The only suggestion I can make is to check the devices where you've seen the problem and verify that there's no drain when the device is idle.

Note that the thread on Candlepower is from 2006 and talks about house-brand Lithium batteries from BatteryStation which don't seem to be available any more.  So it may or may not be the same problem.

Something doesn't sound right about this problem.  Almost everything uses more than one cell.  If this was a real problem, it would be a big deal instead of something that's been floating around for 16 years!

Ed

[Faringdon]

Are you using them in very high or very low  temps?
Really it sounds like you could do with either a balancer circuitry in there...or just simple "stopper" circuitry which stops the pack discharging once any cell goes below  the minimum allowable  cell voltage threshold.
...and Ditto....stops the pack from being further charged when any cell goes above the "too high" threshold.

Bad batteries are a real problem....i once worked in a company whose whole existence span round trying to alleviate "bad cell in a pack" issues.

[f4eru]

It could be an internal contamination issue, leading to a high self-discharge.

Test the voltages before use, see if you have mismatches.

Also, one factor is that their voltage seems to drop near instantly t the from 1.2V to 0.
Many loads are not designed to alert the user with that kind of sharp dropping characteristic, and that kind of higher voltage for a low SOC.

[John C]

I have given up on Energizer Ultimate Lithium AA. I was using four of them in a chip activated cat flap because we wanted reliability while out of the house, but have has several instances of the sudden death of one cell phenomenon.  I've switched back to alkaline there, and am using remaining "good" cells in thing like torches. Interestingly, I did try to use up four in a Hive thermostat. It took literally seconds for one to go from 1.6V to 0.5V when the thing booted up.
Ultimately, I think Energizer Ultimate Lithium AA are unsuitable for in-series applications, or at most two in series in something like a remote control where sudden failure does not lead to a serious problem. The flat discharge curve  and seemingly near instant end of life voltage drop confounds battery level monitoring and makes reverse charging of the first cell to die almost inevitable.

[watchmaker]

I have given up and switched to Panasonic Eneloops.  Can't stand DuraHell and I had several reverse polarities with the Energizers.

[richard.cs]

I've also experienced this in low drain applications where alkalines give months but I wanted to avoid any leakage risk and to and stretch the months out a bit longer (the temperature was also low so I expected the lithiums to work significantly better). This was an outside weather monitor which has a continuous drain of single-digit microamps and a few milliseconds of tens of milliamps every 30 seconds. Instead with the lithiums one cell is seemingly dead after a few days. Changed both, same thing, different batch, same thing, gave up and went back to alkaline.

The phenomenon certainly happens, but I don't see any particular reason it should relate to series use, or to any internal PTC. I assumed it was either some kind of quality control issue or something about the discharge profile that they really didn't like.