why is my battery percentage increasing without charging

[Android Central Question]

My battery percentage increases without charging after playing a game i leave the phone locked and when I check after 15 minutes battery percentage is increased its not battery problem I checked that by using another battery this started to happen after downgrading to kitkat from lollipop and having no network and a cell standby service that used a lot of battery but now network fixed by going to lollipop again but still this problem is not fixed I did the secret calibration code thing and other things too but no luck please help.

 

[belodion]

Increasing by how much?

 

[Inaan riterdo]

The more i used it the more it increases if i used it from 100 percent to 20 percent more than 20 percent will increase after some time while the phone is locked i know its the cell standby service it used a lot of battery because i didnt had network at that time it was searching for network and because of its over limit battery using it messed up my battery percentage reading a fix please

 

[Rukbat]

First, running the battery down to 20% regularly can kill it quickly. (So can charging it to 100%. Try to keep it between 40% and 80%. Use Accu​Battery.)

After a long bout of heavy usage, the battery may bounce back a few percent. That's why belodion asked you "Increasing by how much?" - and you didn't answer. Increasing from 20% to 25% after a while is normal. Increasing from 20% to 80% isn't.

 

[Inaan riterdo]

This never happened before no matter how much i used my battery by gaming and im telling you how it increases if i used my battery from 80 percent to 60 percent by gaming it will increase to 6 or 8 percent after some screen locked time and im sorry if i make some mistakes i never had to get help from these places before.

 

[Mooncatt]

As a battery ages, it can't handle the power demands as well. Rukbat is correct that it's possible to see the percentage increase a bit after gaming and the battery has a chance to rest. As it wears out, this could get worse and you may also see other symptoms, such as shutting off at something above zero on the battery gauge. So if it's gaining 6-8 percent, then I'm leaning towards the battery simply about due for replacement.

 

[belodion]

I've seen small increases in reported battery charge level, both in the percentage figure and at the same time as a corresponding upward incline on the battery usage graph, on various phones. I think it's fairly commonplace. That's why I asked you how much increase you were seeing.

Don't worry about any mistakes. You are welcome here as a new member.

 

[belodion]

...I've just checked the graph on the Nexus 5 I'm using right now, and as you can see, it does show a slight upward incline at a certain point:

 

[Inaan riterdo]

I guess its not much of a thing then if things go too bad ill try replacing a new battery thanks guys.