Are my NiMH rechargeables DEAD-dead?

[FTNR21]

I have a little over two dozen AA Energizer 2450 mAh NiMH batteries that won't charge. They're roughly 20 years old and haven't been charged in at least 5 years. I've tried the terminal bridging with a fully charged battery trick with a few and no luck. My chargers almost immediately indicate an error and the charge cycle won't even start.

They read 0.00v and there's a pass-though resistance of around 0.5 ohms. My other Energizer NiMH AA batteries that are charging normally have no continuity between terminals at all. So, I'm guessing that the fact that there is continuity between terminals on the bad ones and not the good ones, is a bad sign.

So, what do you think folks? Are they dead or is there some other options that I could try to bring them back to life?

Thank you

 

[thermal guy]

20 years? Ya they don’t owe you a thing. I’d scrap them.

 

[hsa]

Give them a dignified burial and buy some shiny new white Eneloops.

 

[bluflaam777]

20yrs is a bit long in the tooth for them even if they've been charged "regularly". 5yrs without a charge after 15 years of use will make them dead. They are now funny shaped bricks. LOL

Someone might suggest trying to revive them via trickle charge...but after this long ...nah.

 

[ebuchner]

Ooof, yeah those are not coming back

 

[MidnightDistortions]

I have a little over two dozen AA Energizer 2450 mAh NiMH batteries that won't charge. They're roughly 20 years old and haven't been charged in at least 5 years. I've tried the terminal bridging with a fully charged battery trick with a few and no luck. My chargers almost immediately indicate an error and the charge cycle won't even start.

They read 0.00v and there's a pass-though resistance of around 0.5 ohms. My other Energizer NiMH AA batteries that are charging normally have no continuity between terminals at all. So, I'm guessing that the fact that there is continuity between terminals on the bad ones and not the good ones, is a bad sign.

So, what do you think folks? Are they dead or is there some other options that I could try to bring them back to life?

Thank you

I got an old PS1 Rayovac NiMh charger that could bring them back to life. Outside of that I don't know of any charger that will charge them and even if they could it's doubtful they'd even charge at a reasonable rate. I have older batteries that will only charge in my Opus chargers at 10mA! They work but ideally unless they are already at a decent charge level these batteries won't fully charge unless I stick them in this Rayovac charger.

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i.ebayimg.com

It would be nice to find more of them or at the very least find some way to just have them charging at the 10mA rate but so far nothing yet and as others have said they're junk and should be tossed.

I use the old AAAs in these sort of dome lights I bought years ago at a walmart which they run great as a night light or ambient light when I don't want a regular light on which would work great in emergencies. You could revive them by finding an older dumb charger which if you can find one that still works.

 

[FTNR21]

OK. Thank you all for your comments. I wasn't holding out much hope because they are really old. I did buy a Tenergy 8-bay charger with a refresh feature to replace the 4-bay 15-minute Energizer chargers that I have, thinking that they might be the problem. The new charger seems to have worked for most but obviously not all.

Now, here's the funny thing. Altogether, I have about 60 of these AA Energizer HiMH batteries in assorted mAh ratings. They're all about the same age, give or take a year. The earliest releases of this model had lower ratings than their successors. The first ones that I bought were 2100 mAh. They all went to that big pearly gated power station in the sky a LONG time ago. What I have left are 2200, 2450 and 2500. So, the 2500's are the "newest" ones. I just cracked an un-opened pack of 2500's that had a 2005 copyright on it. Those, along with the other roughly three dozen used 2500's I have, all charged fine as did the even older 2200's. Only the 2450's are flatlined.

Now, I haven't really used any of the successfully charged batteries yet, so their actual viability is still unproven. As for the dead ones, I get the fact that any of them charged at all due to their age is surprising to say the least, but with only the 2450 mAh failing, makes me wonder if that was a "bad year" for the factory.

Anyway... I stopped using rechargeables years ago when I didn't need them as much and keeping them charged became a real chore. I switched to Energizer lithium disposables due to their 20-year shelf life. Plus, they're "leak-proof" which is a big up-sell for me because I can't tell you how many flashlights that I've had trashed by ruptured alkaline batteries.

The problem with at least some lithium batteries, as many of you probably know, is that they're hot. Energizers are typically 1.70 to 1.80 volts fresh out of the package. Too hot for sensitive devices and pretty much anything else needing more than four cells. They torched a 3-cell AAA LED head lamp a while back and a 3-cell AA LED lantern just the other day.

So, I'm going to try getting back to rechargeables, for at least some applications. Since we're talking about chargers, can anyone offer recommendations for good AA/AAA chargers? The Tenergy that just bought seems decent, but it wouldn't charge some of the batteries that my other charger would. So, I'm not sure if that's a flaw or some kind of safety feature.

I guess I should look at replacing my batteries as well.

Thanks again 🙂

 

[cave dave]

Eneloop Low Self Discharge (LSD) NiMh for the win. I have some that date back to 2006 still working well in low drain devices like calculators and remotes. I have had bad luck with the Pro version going bad after only a few years, but the regular version has been great.
https://eneloop101.com/ website was put together by a CPF member.

Buy only from a reputable seller as their are fakes and non-Japanese versions out there. I buy from Battery Junction.

For a budget option get the Ikea Ladda 1900mAh AA and 750mAh AAA, which are rumored to be made in the same Japanese factory as the Eneloop. I don't have as long a history with these, but the few I have have been just as good. Every other brand of LSD NiMh cells including Duracell, Amazon Basics, Tenergy have been crap.

I used to buy Energizer lithium as well but their prices have doubled in the last 4 years. I still use those for long term storage in a car where they go through hot summers, but even then Eneloops can survive a few summers, be recharged after use and be replaced if they go bad, for less than the cost of one time use lithium.

 

[WC8KCY]

I have a fleet of rechargeable NiMH AA cells dating back to 1999. I use Opus BT-C2000 and BT-C2400 chargers, which are identical units, differing only in that the 2000 includes adapters for C and D cells. These will charge any cell, as long as there's some measurable voltage in the cell when you begin the charge cycle.

If the cells are at zero or negative voltage, I charge them in a dumb charger for 15 minutes, then move them to the Opus; that will put enough voltage in the flat cells for the Opus to commence a smart charge cycle.

The bad news: In my experience, Energizer AA NiMH cells of that vintage that have been sitting around at zero voltage for years will probably have 500-1100 mAh capacity after reconditioning them. Still, I find such deprecated cells useful for deployment in remote controls, where they work just fine charged once a year.

 

[FTNR21]

I have a fleet of rechargeable NiMH AA cells dating back to 1999. I use Opus BT-C2000 and BT-C2400 chargers, which are identical units, differing only in that the 2000 includes adapters for C and D cells. These will charge any cell, as long as there's some measurable voltage in the cell when you begin the charge cycle.

If the cells are at zero or negative voltage, I charge them in a dumb charger for 15 minutes, then move them to the Opus; that will put enough voltage in the flat cells for the Opus to commence a smart charge cycle.

The bad news: In my experience, Energizer AA NiMH cells of that vintage that have been sitting around at zero voltage for years will probably have 500-1100 mAh capacity after reconditioning them. Still, I find such deprecated cells useful for deployment in remote controls, where they work just fine charged once a year.

So, with the internal resistance on the dead cells being 0.6 ohms, is that any indication to how far gone they are? The ones that I've been able to charge have no continuity whatsoever.

 

[WC8KCY]

So, with the internal resistance on the dead cells being 0.6 ohms, is that any indication to how far gone they are? The ones that I've been able to charge have no continuity whatsoever.

Not necessarily; I have some with IR in that range and they still charge up to around 1100 mAh capacity.

Repeated charge and discharge cycles with the Opus charger brings down the IR substantially and improves cell self-discharge, but doesn't do much for the measured capacity.

 

[Henk4U2]

I've got a few chargers with a zero-Volt feature, but if my little XTAR VC2 Plus Master can't revive them, they are really DEAD.

 

[MrAl]

I have a little over two dozen AA Energizer 2450 mAh NiMH batteries that won't charge. They're roughly 20 years old and haven't been charged in at least 5 years. I've tried the terminal bridging with a fully charged battery trick with a few and no luck. My chargers almost immediately indicate an error and the charge cycle won't even start.

They read 0.00v and there's a pass-though resistance of around 0.5 ohms. My other Energizer NiMH AA batteries that are charging normally have no continuity between terminals at all. So, I'm guessing that the fact that there is continuity between terminals on the bad ones and not the good ones, is a bad sign.

So, what do you think folks? Are they dead or is there some other options that I could try to bring them back to life?

Thank you

Hi,

Yeah they are old and worn out. Buy new ones. Eneloop are the ones of choice these days and they have much lower self discharge which means they stay charged longer when not being used.