Rechargable Batteries Remaining Life

[carloszoom3000]

Hi,

I'm trying to find out the remaining charging cyles on NiMH AA 1.2V rechargable batteries.

I'm placing a battery in series with a the parallel of 3 resistors of 2.2 ohms which are 5, 10 and 20 watts respectively.
To log the discharge and using an Arduino UNO and with some visual basic code i can see on every second, the voltage values measured (it also shows a graph).

When checking a functional battery it takes 15327 seconds before the curve shows it's discharge and it takes 9000 seconds on the non functional.

I would like to know what parameters i should take into account to know the remaining charging cycles.

Regards,

 

[Alec_t]

As pointed out on another forum, the number of possible charging cycles can not be known, even by the manufacturer.

 

[carloszoom3000]

Thanks for replying.
If the exact amount of cycles cannot be calculated, is there any measured value or performance shown by the batteries that can be used determine or estimate regardless of how often the batteries are used in let's say a 6 months period if the batteries should be replaced by then or not.

Regards,

 

[Martaine2005]

Hola Carlos,
As Alec_t has explained. Manufacturers don't even know.
All they can do is give you an idea. Most say 'more than 1000 charge cycles', others say 'upto 1000 charges'.
It all means nothing really. It totally depends on how and where they are used, charged and discharged.

If the battery wont charge properly, you can try cycling by charging and discharging several times to clear the 'memory affect'.
Also, some people fully charge their batteries ready for storage. That is not a good idea. Best to store batteries discharged.
So there really isn't an answer.
Lo Siento.

Martin

 

[carloszoom3000]

Hi,
Sad to hear that.
I've read from manufactures like eneloop (panasonic) that depending on the battery they have an estimated quantity of cyles for recharging.
As it's hard to count the amount of cycle that have been performed, that's why i wanted to use the discharge curves, comparing a brand new battery with an already used but still ok battery and see the differences.

Regards,

 

[Martaine2005]

I've read from manufactures like eneloop (panasonic) that depending on the battery they have an estimated quantity of cyles for recharging.

Yes they do ESTIMATE, because nobody knows.
I would think the discharge rate would be slightly different for any individual battery. Even from the same batch.
I would also say that a properly used cell could out perform a brand new cell.

Also, using the same resistors for different batteries wont help much either for your scientific experiment.
Each and every individual battery has it's own internal resistance too. So that would also affect your results.
Viva Londres!

Martin

 

[tom knutson mn usa]

Specs vary on your use, it is presumed 500-1000 times
The actual number of times will vary base on use and charge
e.g. does the battery get charges when it iit is 3/4 full, not recommended
e.g. does the battery get charged when empty, mostly empty
e.g. rain or moisture
Most engineers would say - estimate & promise the low end of 500, and
if it does better you will look like you did good