Bit of a generalisation and over simplification here, but.....
The vast majority of batteries don't like being anywhere other than fully charged. Deeply discharging one is akin to 20 years of Full English breakfasts and no exercise. So like feeding people too much fatty food they 'furr' up. At idle or little activity they work as expected, but make them run a 100m sprint and they give up before they're out of the blocks.
So, if at all possible, keep your batteries fully charged, preferably with a 'clever' charger, like an Optimate or such. That will make the battery last a lot longer, but remember they are disposable items........