Internal resistance- is it curable?

since i get advanced charger/analyzer i tested some of mine older nimh batteries internal resistance...i have tried 4 white eneloops, several years old, and one of them have IR of 800, and the rest between 400-500...

after full refresh i get around 1900mah capacity, and IR dropped below 100...

my question is: are they cured of high IR, or is it creeping back just around the corner? are they still good to use, or is this back to life only temporary?

This is impossible to say. Sometimes, high internal resistance is reversible with a few cycles. But other times, it's not. Also, it's impossible to know whether high resostance will come back. I would say that if internal resistance remains low after a few cycles, you are probably good for at least some time.

Yeah, more often times then not, high IR is very hard to keep away once it starts, what charger did you get?

RCM said:

Yeah, more often times then not, high IR is very hard to keep away once it starts, what charger did you get?

Click to expand...

Japcell BC-4001...some version of Opus BT-C2000

High internal resistance can only be cured with battery replacement

it really fluctuates a bit...i checked some panasonic infinium batteries, and the 4 of them have IR somewhere over 100....after disharge and charge 3 of them went below 100, but one of them jump to 295 IR? it looks like it is coming and going, i still can't find a pattern...

I saw a video in which someone injected water into a NiMH AA cell to improve the short-circuit current. It worked for him. I tried it too and it seemed to work quite well, but it's pretty hard to get the needle in the battery. Also, it doesn't work with all batteries, because the hole above the safety vent is too small on many batteries.

Here are mentioned videos (unfortunately it's in german):
https://www.youtube.com/watch?v=pzsPMPg0YFU
https://www.youtube.com/watch?v=_0gvSqtGXvA

Poking a needle into a battery is a good chance to see fireworks. Advices like this remind me a method of making ones **** large with a help of a hammer...

They may be cured for now, but at the value you give, they probably have most of their useful life behind them. You didn't give the size, but for AA cells I'd estimate to be about 10-20% of their cycle life left, for AAA cells it would be about a third... depending on what you take as the end of cycle life (80% of capacity or less).

I already have "cured" cells of high impedance myself... one set of 3 AAA's came off a wireless phone I had back then, and had been mistreated by steady overcharging. One deep discharge got it going again, but some months later, it showed the same symptoms again, and this time the deep discharge didn't help much anymore.