10440 to replace AAA

If you have no use for NiMh longevity that approach can be used. Initial battery quality, capacity, and then use pattern ALL affect the ultimate longevity of a battery. Higher capacity NiMh of the same size, tend to deteriorate faster than lower capacity. This is from an interview of 2 Eneloop technicians:

**What is the differences from a technical and design/construction of regular Eneloops and Eneloop Pros that allow the regular Eneloops to retain charge for longer and have more recharge cycles and the Pros to have a higher capacity?

More volume is more capacity. The Pro batteries have a thinner canisters so there is more active material and electrolyte . The reason why there is a difference in the cycle life is the difference between the amount of the positive and negative electrode. The bigger the difference the more cycles it can have. With Eneloop Lite being on the exact opposite of the Eneloop Pro.

The ‘regular’ Eneloop spec is 2000 cycles, the Eneloop Pro is 500.

In my ‘real life’ use of rechargeable batteries, going on 20 years now, I’ve found this to absolutely be true. AA NiMh that I have over 2500mAh, rapidly ‘go to hell’, (2800 NiMh go to hell fast) and aren’t worth much after only a few years. At……very low……discharge they may show capacities are aren’t too bad, but they stop being able to put out any kind of current, the IR goes WAY up, and the charging gets unreliable in ANY charger.

Then……as is being discussed here, there IS differences among chargers, especially with regard to accurate termination of NiMh, which is actually more difficult than Li-on.

I don’t toss a NiMh for simply losing some capacity. I have applications that can still use them. I DO recycle them when the capacity loss is excessive, and/or the IR gets too high and termination becomes dicey.

Also note that running 4s nimh increases the odds a call will reverse.
3s should work fine and when you hit 1v/cell you are very near vf of the leds.
So its self limiting and not as likely to reverse a cell.
Reversing a cell damages it.

I agree that although Capacity may sound as the Holy Graal, other points need be considered.

My (limited) experience is (AA format):

  • GP ReCyko+ 2050 mAh: still very usable, and moderate IR, after 14 years!
  • Maha Imedion 2100 mAh, 13-year old: rather high IR, but as flydiver said, still quite usable in low current devices
  • Maha Powerex 2700 mAh, same age: I had to trash two of them after only 5 years or so, because of major capacity loss and high IR. Two other units are still usable but have high IR. This may back up flydiver's statement on high capacity models.

In AAA size:

  • 14-year old GP ReCyko+ (820 mAh) still behave very well,
  • 12-year old Maha Imedio (800 mAh) are also still OK,
  • 9-year old Varta Ready2use (800 mAh) still good as well,
  • Duracell 1000 mAh and Maha Powerex 1000 mAh were trashed after a couple of years (and few cycles): again a confirmation of "higher capacity = lower lifetime"?

I bought more recently (less than two years) Varta Ready2use in their more recent version (1000 mAh), too early to evaluate them.

BTW, which IR values are considered good, fair, and bad, for NiMH batteries?

[quote=Rockenrooster] I need a battery that will last for years and years to come and no other batteries come close to Eneloop/fujitsu [/quote] Any source to back up this statement?

quick 10 sec google search:

Interesting Rockenrooster, but to conclude they are "better than others", "others" should be tested in the same 10-year old conditions. And how about IR?

IR testing depends a lot on HOW you do it. Some analyzing chargers have an IR function. BUT….due to sliders and contact resistance that reading can be not terribly consistent or reliable. I have 3 chargers that will do IR. Best one of the lot was Zanflare C4, followed by Opus BT-C3100. The Littokala Li-500 was useless, always giving exactly the same IR for NiMh. I’ve tried 3 of them, all the same. Good charger otherwise though.
I finally got a dedicated discharger: ZB206+ and 4-point cell holder for the job. Much better, and consistent. Great device.

The numbers you get are also only loosely comparable. There is a method to do it with a good DVM that gets consistent results but I wanted the discharger function and didn’t want the hassle of using a DMV.

The IR also depends on size with large cells generally being lower than small cells.
All that said, good AA is under 50, OK is up to 100, degrading is 100-200. Over that they start to get dicey. AAA will be ~ 50% higher. And those numbers are my opinion, for my cells, with my equipment. Best to try to measure using the same equipment with the same technique over time.

Yeah IR testing is difficult and can only be used relatively, meaning you results will be different than mine kind of thing.

I’ve had rayovac and energizer NIMH batteries and those have been trashed long ago.
However I do still have a couple rayovacs, as they were lower capacity than the energizers.
I also have some old eneloop pros that still work great, but I don’t know where they are ATM lol.
Also, my brother has/had some Powerex NIMH, forget what capacity, but i know they were less than 4 years old before they got throw away because they could hold a charge.

Also i don’t know of any other decade old battery tests other than eneloops, probably because other would be trashed before then.

12 year old eneloop test:

If you do have a good IR setup, getting consistent results, it can be pretty useful. I finally got the ZB206+ and holder due to inconsistencies in capacity testing between various chargers, and even the same charger using the same settings.
That said, the inconsistencies were often the result of testing OLD batteries. Termination, cut-off, and self-discharge can be highly variable for old, high IR cells.
Those need recycling I found. Be rid of the headaches.

Thanks folks for your reply Re. IR.

My first attempts to measure it with my Opus BT-C2000 charger used to give very widespread results.

Now I use my BT-C100 to test batteries one at a time, 5 times in a row and pressing hard the slider against the battery, following advice given somewhere else on BLF. This gives me much more homogeneous results, and I keep the lowest value obtained.

With this method, I find that the worst I have are my 12-year old Maha Imedion AA (700-900 mΩ for two of them, 350 mΩ for the other two), and the best are 4 out of my 8 13-year old Varta Ready2use (around 150 mΩ). The 14-year old ReCyko+ are also around 150 mΩ, still not bad for such old batteries.

9-year old AAA Varta Ready2use are still below 100 mΩ, whereas 12-year old Maha Imedion reach 470 and 770 mΩ (but these two were used for a long time in a DECT phone, i.e. permanently charged at 100 % which is not good for battery life).

Those Varta looked interesting. Unfortunately on Amazon they are $28.47 for 4.
Fujitsu 1900mAh were $23.54 for 4.
Eneloop 2100 were $18.99 for 4 (plus the fake issue.)

Most of the ‘cheapies’ with more capacity, that I don’t trust, are much less expensive. Make your choices according to information collected + your belief system. :smiling_imp:

In Europe we can get them as low as €6.45 (nkon.nl), but the shipping cost to the US (€19) is a strong deterrent unless you buy many units.

A little more shopping and found the Varta 2100 on eBay for $12 for 4. WAY better. Free shipping from Lithuania. Huh!

If If If you got a buck-boost driver to adjust to 6V, then yeah you can use 2 cells in series, but keep in mind the voltage will range from 8.4V out of the charger to as low as 6V or lower when completely spent.

And they’d better both be protected cells because when Li-ion cells are in series, likely one will get discharged too low and fry it or get it fizzing.

Aacycler.com

Hmm. I always thought a larger capacity would give longer life. For example, I had a new battery that I had put in a 6 cylinder car that was of larger than necessary CCA. Car bit the dust just a few months later so I kept the battery & put it in a Honda Civic. There was a prety good system in it. 2 amps (about 2200 watts), & that battery lasted a really long time. This includes listening to the system with the engine off for a couple hours at a time.
I do however have Tenergy 9v 200mah in my smoke detectors that are at least 5 years old. The only other type of NiMh I have used is Energizer.
I was going to buy some of the 1000mah AAA from Tenergy, but after reading this I may buy the smaller mah ones.

Car batteries are completely different. Not to mention you are comparing different things.

Amp Hours are not Cold Cranking Amps.

Think of lithium batteries in flashlights. A Samsung 30T won’t have to “work as hard” compared to a Samsung 50E in something like a FW21 Pro that can pull almost 20amps. But the 30T has waay less mah.
That Samsung 50E won’t be as bright on Turbo, not to mention will kill the battery and make it unusable after several cycles running crazy hot on the verge of blowing up.
That Samsung 30T won’t break a sweat for its entire lifetime because its rated for that output.

Overkill in the correct way will make something last longer.

That’s indeed a great find, I see Eneloops and the Fujitsu batteries at the top of the chart for “regular” AA rechargables

Can’t really compare Pb life to NiMh life. Pb likes to be kept fully charged. All it takes is a few deep discharges (lights left on kind of thing) to ruin even a good one.
NiMh does best kept to 20-80% if you REALLY want it to last, but that’s very difficult to manage. It’s quite happy between full and 1.0v. LSD types are damaged by constant trickle charge.

I have a dozen Tenergy 800 AAA from 2017. They get regular use and are OK. Most are now in the 600+ - 700mAh capacity.
I saw they now have a Premium Pro 1100. I’d only buy them if the were $1, to check them out. Doubt they would hold up for the long haul, which an important variable to me.

So are you saying that 4 1.2s are not a good idea? I also was thinking of running 4 in my 2 way walkies as well.