Battery percentage update

[Kratarth]

I'm using a Lumia 638. When I put my phone on charge, it shows like 2-3% even for like 10-20mins and even you check later on it shows random number like 80% or any, sometimes it even shows 100% too quickly as if it is fully charged. When I use my phone, it shuts down on any percentage, let's say 40% with a battery error as if it was on 2-3%. I'm not sure if it's the problem of wrong battery data percentage but I've just got new battery installed. This one works much longer than my last one. I've hard reset my phone before. Its build is 15063.608
No new update I see. Is there any new available? Let me know.