I have a pretty new Nokia Lumia 620 (15 days of life).
I'm very careful with it, especially regarding battery care. I have read a lot of papers about proper battery usage now and two years ago when I bought my new laptop, so now I know almost everything on how to use and recharge Li-ion batteries in the proper way.
I'm also care with regarding battery consumption. Sometimes, when I know that I'm not expecting to use my smartphone in the next few hours, I check its battery consumption rate when it's completely idle (smartphone on but with lock screen).
All the apps in background are disabled, except Whatsapp.
My curiosity arises by the observation of the battery percentage before locking the screen and after 3 hours immediately after resume with the smartphone never used.
Sometimes before the lock screen and after the smartphone resume the battery level showed is the same or 1% lower (after 3 hours), other times it is 6-7% lower (always after 3 hours).
Why a so high difference?
I must mention that the smartphone is placed always in the same place, so there are no difference of network coverage or so on.
It is only a curiosity on what can be the reasons.
Thanks a lot.