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    Charging NiMH batteries

    Does anyone know what it means when a battery charges past its capacity. For example I am charging a 1300 mah AA battery at 700mah yet it is now at 2620mah and still not finished, it's getting quite warm, it's at 1.42v not sure what the cut off point is probably 1.5? But surely it can't be holding 2620mah of power, I did discharge the battery before charging it too. Is it a bad battery or the "memory effect" or something?

    7 Comments

    They do get very hot when charging. Uncomfortable to hold hot. I also hit the discharge button on the smart charger that drains them right out before charging. I can't tell you any more as not a tech guy.

    As it hasnt already exploded, it isnt charging at 700mAh; that might be the setting you selected, but hopefully the charger has enough circuitry to to set the limit to what the battery will take.

    I suspect either the battery isnt charging at all, or it is not holding a charge long enough for the charger to stop; I have had a few like this, especially older ones - the latter as you say it is getting warm (normal).

    Too hot to touch comfortably is the danger sign.

    Try cleaning the terminals, letting it cool overnight and try again; it might also be your charger slowly dying; I had this a few months ago, some cells wouldnt charge, others would. Put them in a new charger and they all charged.

    well i would stop at that what are u waiting g for a explosion aren't rechargeable batteries 1.v fully charged take it off charge and take a reading after say 2 hours to see what the reading is or just use the batteries no point trying charge it more and more to blow it how long u been charging it for 700mah at what v is the out put on charger

    Nimh batteries are finished. Newer ones are all lithium.

    sam_of_london

    Nimh batteries are finished. Newer ones are all lithium.


    Which explode with an even bigger bang!

    Original Poster

    Thanks all, I was going to throw out the battery anyway (well put in recycle bin) it was one of my brother's ones, when I charged it it was only holding around 400 something mah on a 1300 mah rated battery, uniross so a known brand. I have a break in and refresh function on charger but not worth bothering really. I just wondered why some batteries get so hot despite charging at around .6 C
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