[bwbmr]

Same here, lots of leaks-- some family even has had a drawer full of unexpired Duracells leak. Myself, I've switched over completely to NiMh except when unsupported by the device to remove the change of leaks (Nest x Yale door lock in particular, which detected NiMh as low battery even when 90% of the cell capacity is remaining). AmazonBasics has been bad with leaks too.

Edit: I have a Powerex MH-C980 and that has significantly made using NiMh easier. Before with a bundled Panasonic charger I had to charge everything in pairs, 4 max. The Powerex I can charge 8 cells individually, turbo charge if I'm in a rush, and see how much energy actually was used if something seems to be eating through a lot of batteries.

[Moru]

Just to clarify your point there: Charging batteries as pairs is what kills the rechargeable batteries. There is no way for the charger to keep track of both batteries at the same time so it just charges until both should be done.

If one of them is bad, the charger will kill the other one too. If they are differently charged, it will kill one of the batteries and next time it will kill the other battery. (Kill as in make worse and worse until it finaly doesn't charge at all.)

I have mostly stopped using rechargeable AA and AAA batteries because of the bad quality of the last ones I bought. They took 3-5 charges before dying with a good charger that does all batteries separately.

[MaKey]

Modern chargers are microprocessor controlled and are able to keep track of each battery individually.

[Moru]

Yes, but only the ones that does not require charging in pairs. Most people only use the bundled chargers and they all work with pairs.

[alliao]

I have an eneloop bundled that charged individually... BQ-CC55

[mnw21cam]

I have never seen a charger that charges in pairs. Every charger I have ever used or seen has charged each cell individually. Charging in pairs is a terrible idea - the chargers should be returned as unsuitable for purpose.

[jandrese]

This is what killed me when I started swapping Alkalines for NiMH in the 00s. Every single charger sold in stores only charged in pairs, and because even then USB was creating a 5V world most things that needed batteries used 3 of them.

Even the charger that Panasonic sold with the Eneloops requires matched pairs.

The other issue being that NiMH seems to top out at AA size. Finding C or D sized rechargeables is basically impossible.

[2muchcoffeeman]

There is a more expensive eneloop charger that does individual cells. I have been mixing cells for charging for years with no problems.

[exhilaration]

I got the Panasonic advanced charger (BQ-CC17) in 2016, it charges individual batteries. Amazon link:

https://www.amazon.com/Panasonic-K-KJ17M3A4BA-Individual-ene...

[zackees]

Also, NiMH batteries can reverse charge and ruin themselves. This happens a lot when batteries are in series and the load will continue to run the batteries until 0 voltage. The weakest battery will deplete first but then the other batteries will continue to pump current through until that weak battery reverses polarity and wrecks itself.

[hilbert42]

Correct, ages ago, I was testing a batch of them and came across several reversed charged ones. At first I thought I must have got my multimeter leads reversed but I found that was not the case.

For a long while I kept them to prove the point to anyone who thought I'd must have lost my ability to distinguish plus from minus.

[stjohnswarts]

I just replaced some ~2 year old 9v and AA from various detectors around my house, all rayovac and half were leaking and I had to use some sand paper to clean the terminals. Yeah I know you're supposed to replace once a year but it is what is. Seems from this thread people have seen leakage from many different brands from cheap ones to "duracell"

[jhoechtl]

Use vinegar to clean the terminals. The base will reduce the oxide and help to clean the compartment as a whole.