somersettr wrote:
I find my batteries self-discharge when they are not in the camera for some reason. Which is unusual for a lipo. I haven't measured the rate but, if I leave one fully charged for a couple of weeks it will certainly need recharging before I use it again.
I never saw this with Olympus batteries and lipos I use in other areas also don't do it so I don't know why the Sony ones do.
All batteries in the world self discharge over time, but slowly.
And more importantly, batteries also lose capacity even when not used, and it loses more capacity if it was stored at 100% than at 50%, and will lose even more if it was completely discharged.
For example, if you store a Li-on battery somewhere at 40 degrees Celsius, charged at 100%, it will lose about 35% of its capacity in a year, so even when you fully charge it later, you only get 65% of its life.
When you see your battery level going from 100% then quickly dropping to 65%, my guess is that the battery had already lost about 30% of its capacity. I see something like that happening all the time on devices like laptops and smartphones after they've been used for some time.