Eneloop pro battery 2500 overcharged to 3600mah. Help please!

If we are getting technical. The things we are talking about (NiMh, or alkaline, or even NiCD) are cells. When you combine multiple cells in a pack, you get a battery. So a car battery is a battery, because it combines multiple cells into a single unit. Honestly though, few people pay much attention to this and just call primary or rechargeable single cell units, batteries. Even though it is not accurate. Bottom line, people will know what you mean if you use either term, but cell is correct.

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glad they worked

when I use Eneloop,
my charger stops when they reach 1.41V

I do not empty the battery first, but I usually charge when my flashlight gets dimmer than usual. When I measure the voltage they are at about 1.2V

hopefully you will continue to learn how your batteries behave. I agree youre doing a good thing by checking that they are not getting hot… hopefully it was just a bad battery, and now you wont have that happen again

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Hello Rockenrooster! I am so happy to read so many interesting comments, and yours is so good and I learnt a lot.

So thet are charged when they are heating up…but how much? the other day…the batteries were scorching… I could not measure as I lend my digital thermomether to my mother… But how many dregrees do you think can be to much?
I was about to buy the CC65 charger as it says the actual mAh the battery has at the moment, but I have “old” batteries that I thought the new powerex pro could repair them…

By 1 amp charging you mean 1000 mA? Ok…so If I let the battery charge and the charger does not stop…the mAH will go up and up…

Ok…so after reading all your comments, overcharging would be to let the charger charge more time than neccesary and the bad thing of this is heating that can ruin the battery if you do this many times.

Ok, Thanks…I did not know that nimh batteries cant catch on fire…

So… Do you recommend using a fan to cool down while charging? Luckily I always take a lot of batteries with me to the weddings, so I can change them if the flash starts to refresh slower.

I will test charging at 800mA and see what happens. However, the amazon ones are giving errors in my flash…


hello zoulas! what do you mean with that? do you say that because it has the discharge option? What charger will you recommend me to charge this kind of batteries?

The MH-C980 is a bonafide charger for rechargeable AA and AAA batteries, it will charge them and maintain them for longevity.

What you have is an analyzer. Its primary function is to test and analyze batteries whether they new or used.

Like I said your analyzer can charge batteries but that is not the intended primary function.

The C980 will charge your batteries perfectly and completely unattended. It has two simple buttons to control it.

This is of course my opinion but I do own both. You can read up on it if you have the time and enthusiasm.

It sounds like making money from weddings is what you do so how much time do you want to dedicate charging batteries.

Get the right tool for the job.

You keep saying this, but it is simply not true. The 9000 Pro is a perfectly capable charger. Plus it can analyze and do an IEC compliant Break-In cycle. Unless his unit is faulty he should have no problems charging his cells with it. I have three of the previous version chargers. The new Pro version uses the same algorithm. Mine have charged literally thousands of cells and I have had no problems.

That being said, the MH-C980 is also an excellent charger. Obviously if dealing with a bunch of cells, having the 8 bays is nice. But some flexibility is lost. I sincerely doubt that it charges cells any better than the 9000 Pro, though.

NiMh charging is quite tricky, chargers normally rely on dV/dT to detect “full”. (d being delta, or “change” and V = voltage, T= temperature).

When the cell is approaching full, the temperature increases suddenly and the voltage goes over a peak and drops slightly.

What I meant by 1.2A being sufficient current, is that (very generally) the higher the current, the bigger the dV/dT signal is for the charger to detect.

With 2000mAh AA cells in my old NiMh charger, I found that 0.5Ah charge setting would miss the termination but 1A worked well- I forget the exact rule of thumb for capacity Vs charge current.

For an extreme example: Charging a 10,000mAh D cell at 0.2A, will probably result in overcharging, because the “full” signal will be too small for the charger to detect.

If you find a multi-chemistry mass produced charger which charges NiMH cells without excess heating… hold onto that thing and never let it go.

I’ve tossed chargers before for being beyond an acceptable level of bad on NiMH termination. I had a NiMH-specific charger that came pretty close to melting its own plastic by the time charging stopped.

This is why cell manufacturers often include ultra-slow chargers. There is no damage to cells when the cells only have to dissipate a couple hundred mW of heat energy.

Which is why the 9000 pro uses temperature as one of the parameters to determine termination. I have never had it overheat cells. My 808M OTH, has missed termination on AAAs using the low charge rate and they get much hotter than I consider to be acceptable.
Letting those rest and charging in the 9000 at half an amp, they terminate properly.