It occurred to me recently that I haven’t changed the battery in my DQG Tiny AAA. Like, ever. It has been on my keychain and used frequently for about a year and a half, and never got dim. But I don’t use it for very long at a time, usually just to or from the car or the mailbox or to light a keyhole or whatever. On low.
So, I took the battery out and ran it through a reconditioning/test cycle on my charger. It was down under half of its rated capacity, and after reconditioning it recovered only to about three quarters.
I’ve also noticed that Eneloops tend to spontaneously recover a fair amount of voltage after being drained.
What I’m wondering is if it’s possible to actually damage Eneloops by using them too infrequently, at low current, for relatively short amounts of time. It seems like this could push the cell down below a healthy voltage and then it would recover some of its charge on its own, and then it gets drained again, then it self-charges again, and so on. And in doing so, it might rapidly use up those “1500 recharge cycles!” it’s supposed to have.
Is this a valid concern? Is it actually better for the battery if I push it harder or use it for longer and force it to need actual recharging? Or is it okay to treat it as a battery which never needs charging because it self-recovers enough between uses?
I noticed some similar behavior when used in a wireless mouse, which takes several weeks to drain the battery and is pulling a very low current almost constantly. The battery there got down to 0.1% capacity (first recharge was pitiful), then recovered up to about 1, 10, 70, then 90 after reconditioning.
Sounds feasible. When I was fooling around with LM3909 LED flasher IC's years ago I read that it could flash an LED for longer than the shelf life of the cell it was using. The low current was better for the cell than sitting idle. Those were primaries of course, but shows there's more going on in there than most of us think.
I too have had a problem with some eneloops, but aa black XX,s which i have hardly used. Mine seem to have built up a high internal resistance, which i only noticed when i put them in an nitecore ea4 . Fully charged on turbo the battery indicator would flash immediately, also in a single cell jetbeam wl-s1 it makes the driver buzz and the ui cell indicator show 50%. Not so with my many used normal eneloops of the same age [2 yrs].Lack of use seems to have hurt my xx’s.
I noticed that putting a AAA in a twisty light drained the battery to nothing in a month (BD-0), i suspected there is some draining occurring through the micro scored anodizing in the threads.
It was a rayovac but it took two conditioning cycles to bring it back to life, i retested a different battery in the light and few weeks later it was also half drained (LSD) so i think that might be a factor to consider if yours is a twisty
I had an Ikea NiMh that out of the package was at 0v and I was able to fully charge it. I’ve run 3 discharge tests on it and the results seemed reasonable. One was after it sat for 3 month and it still had 90% of its rated capacity.
Of course there’s no way to tell if the life span or number of cycles has been impacted.
In general I recall trying to never go below 0.9 V under load to avoid damaging the chemistry, which is important since resting voltage pops back up quite quickly.
I’m seeing kind of the opposite issue… which is that the battery never drains. It’s in a DQG Tiny AAA IV, which is a battery-crusher style with no anodizing. It has zero current when it’s not fully tightened, so the voltage recovers between uses.
In any case, I’m mostly just trying to figure out if I should be pushing my infrequently-used lights harder so I can drain the battery faster and be able to tell when it’s low… because otherwise I might be keeping the cell perpetually almost-empty and letting it self-recover between uses in a manner which might damage the cell. I just don’t know if it actually works that way.
Mine had zero readable current, i suspect it uses microamps.
An easy test would be for you to have two new or identical history batteries, one in the light and one outside, fully charge both the same day and see what happens in a few months. If you don’t have two with the same history at least two that are similar age and not the one your having problems with.
In my case i used Rayovac hybrid batteries, i had 8 of them, wit one in the light, in several months the one in the light was empty and the other 7 were at 75% (or took 25% charging so maybe 80% charged if you consider charging efficiency). Next i did what i mentioned above, used a different battery and left it a few weeks, and it was about half drained vs about 80% remaining for the rest (maybe 85% for the rest with charging efficiency).
Er, there’s no anodizing; it’s bare metal. No attempt to block current between the body and head. No spring. It simply untwists far enough that the battery no longer makes contact. It has an air gap when not in use, rather than relying on a layer of anodizing.
If it had a constant low drain, I’d be having opposite issues like the battery getting low too fast…
As for constant slow drain, that’s something I’ve had more experience with.
I use a Zebralight as a night light. I aim it at the ceiling on moon mode (spec’d at ~0.3lm, actually ~0.1lm) and leave it that way all night, turning it off sometime in the morning. An Eneloop lasts about 2 months per charge like that, and I haven’t noticed any detrimental effects on it. However, I haven’t tested in detail. Will have to do that next time the battery gets low.
I sometimes do the same with the starry light, on super low or low, but i throw it on the charger every few days since i use it outside of nightlighting, its threads are wearing out
Perhaps you should do some testing in your DQG tiny, leave the battery for a week, recharge, and work your way up, two weeks, a month, 2 months, 3 months, 6 months and see what your results are
Testing this would take a long long time. I think I should just use the light more often, and use it on high instead of low, so that it’ll actually need to be recharged once in a while.
