Phone switches off after reaching 20%

[XymphosCraK]

I recently (and accidentally) deleted the pre-installed power saving mode on my phone. Now when my phone has less than 20% battery it switches off instead of saying "entering battery saving mode".

Kind of a newbie here so if someone else has posted a solution or this is in the wrong place please do tell me! Its really bothering me how I only really have 80% of battery potential.

Thanks,
XymphosCraK

 

[UJ95x]

Which phone are you using?
How did you "delete" the power saving feature? Are you sure it's not just disabled?

Sent from my Galaxy S4 running SlimKat 4.4.4

 

[Golfdriver97]

Are you rooted?

 

[XymphosCraK]

Honestly no idea .-.

 

[XymphosCraK]

Using an old Sony Ericsson, not completely sure which one (that's how hopeless I am). There was this Power Saving Mode app in the app list, deleted it because I was running low on memory (delete as in pressed the "edit apps" thing at the bottom right corner, then clicking the X)