Excessive battery drain after restart [J5 2015]

[GalaxyA51user]

My dad's J5 had a SIM card error, and moved the card from SIM 2 to SIM 1. Home screen wallpaper changed (without reason, not a big problem) and exessive battery drain from 70% to 33% after removing battery. Battery not swollen. What may be the reason? 

[BandOfBrothers]

It's probably going to be a case of troubleshooting steps @GalaxyA51user 

• Try your sim card in another phone as a process of elimination to help rule out a sim card issue.
• Clear your phone's System Cache Files by turning your phone Off and then from a set series of button presses go into the phone's System Files and clear the cache. No information is lost this way. You may need to insert your headphones or hook upto a computer with your data cable to get to this menu on the phone. https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/ No personal information is lost. 
• Last resort is a back up and factory reset.
• A Samsung Experience Store or Samsung Service Centre can take a look.

[GalaxyA51user]

Thanks, SIM problem, I moved SIM card from slot 2 to 1. Card worked, 4G worked and Google opens (which means Internet working fine). But now, the battery problem. 6 years of usage, battery needs to change now.