Originally Posted by DakarM

yes and no. it depends on the quality level of the cells that was used to make the battery.

there are about 20 different grades. starting at A++ . anything above B grade will last wayyy longer. For example we have IBM original batteries from 3 years ago, which has been sitting on the shelf and 10/10 on average retained 98% of the capacity. IBM obviously specs out A grade cells.

For smaller batteries such as digital cameras and cell phones, it makes an even smaller difference between grades.

The only time you will lose 20% is if it is stored in elevated temperatures (100F) consistently for months at a time.