Author Topic: how should I interpret a Li-Ion battery capacity?  (Read 1145 times)

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Offline eyal

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how should I interpret a Li-Ion battery capacity?
« on: May 18, 2015, 08:28:07 pm »
If the 18650  battery (from a reputable manufacturer) says 3400mAh (or 2400mAh), how do I verify this? Discharge at 1C (3.4A, probably too high) 1A (0.3C, looks reasonable to me)? 0.5A? Is there an acceptable discharge rate that the capacity is quoted for? I use an imax-B6AC which is adjustable.

cheers
 

Offline Psi

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Re: how should I interpret a Li-Ion battery capacity?
« Reply #1 on: May 18, 2015, 08:28:43 pm »
i'd expect the rated capacity to be from a 0.1C discharge
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline amyk

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Re: how should I interpret a Li-Ion battery capacity?
« Reply #2 on: May 18, 2015, 11:19:52 pm »
Look at the datasheet.
 

Offline eyal

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Re: how should I interpret a Li-Ion battery capacity?
« Reply #3 on: May 19, 2015, 12:17:52 am »
Naturally I did, but I could not find the exact battery doco. It seems that the typical capacity is usually above the one on the label, and for this one (a 2700mAh) the capacity changes only from about 2800 to 2900 with discharge rate between 0.2C and 2C. The link I checked is this
    http://industrial.panasonic.com/www-data/pdf2/ACA4000/ACA4000CE240.pdf

So it seems my test at 0.3C is valid and does not change by much at sensible discharge rates.

cheers
 

Offline jeffaroo

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Re: how should I interpret a Li-Ion battery capacity?
« Reply #4 on: May 19, 2015, 12:46:47 am »
Check out lygte-info.dk site for the mother-of-all battery reviews.  It's a bit hard to navigate but it has a wealth of information. Perhaps start at http://lygte-info.dk/review/batteries2012/Common18650comparator.php or at http://www.lygte-info.dk/info/indexBatteriesAndChargers%20UK.html.

Even if you don't find your exact battery you can see examples of typical battery discharge curves at different rates.
 


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