Galaxy S4 mini battery drain

[LauraSAnn]

Hi, I wondered if anyone could help...

I have a Samsung Galaxy S4 mini and my battery seems to drain really quickly. When taken off charge at 100% at say 10am by about 8pm it's down to about 17% (on a good day!) I have the phone in power saving mode, and during the day the phone only has minimal useage - ie. sending one or two text messages, max 10mins (throughout the whole day) on facebook etc.

I have the G-Sam battery monitor installed but how do I know whether what % the phone is using for each feature is the right %? 

I've read a lot of suggestions for people with similar problems to do a factory reset on the phone but as I'm not very technical I don't want to do this without knowing it's definetly the right thing to do!

There must be something wrong somewhere as a friend has exatly the same phone but runs more apps and uses the phone alot during the day but they can get over 36 hours on one charge! 

Thanks in advance for any help!

[hrym]

It's possible that your battery is nearing the end of its life.   If it's removable, take it out and lay it on a flat surface.  Can you rock it?   If so, that's evidence of swelling and confirmation that you need a new one.   Lithium batteries generally have a charge cycle life of 1000 times, but that's full-charging and top ups are pro rata.  Their life can be considerably shortened if they're allowed to go completely flat.   Regular topping up is good, unlike nickel based ones.

If it's not the battery, I'd try a data monitoring app and see whether there's an app that's using more data than it should.  That won't show non-connecting usage, of course, but it's still worth a try.  The battery use percentages are difficult to interpret for two reasons: 1) they only show the proportion, not the actual consumption and 2) it depends on what you're doing.   In normal conditions, either the display or the OS would be running at 50% or so.  If anything's vastly higher than that, it would be a bit of a clue, though.