iphone 5s sometimes not charging

Did you use other than Apple (or Apple-certified) chargers?It yes then there is a good chance those chargers damaged the charging IC on the logic board. Another possibility would be bad cable (which you ruled out) bad battery or bad charge port. Anyway buy a cheap USB ammeter, and confirm that iPhone is not taking current.

If you have Applecare, then perhaps simply use it at Apple Store/AASP? They have free diagnosis at Apple Stores. This seems the cheapest option - all others carry cost of some repair.

When you plug the cable into the phone, does the cable go fully in as in does the plastic of the cable meet the metal of the phone (should be very little gap) if it doesn't then your phone likely has dust or fluff in the charging port which needs to be cleaned out properly...

I would say the battery does need replacing now because I always feel iPhone batteries are on their way out if you ever see it at below 5%, usually they switch off when they are 5% and when you put them on charge and they come back on they should be at 5%, I always think if they come back at 1%-4% or above 5% theres some kind of battery problem...

Hi

If your battery is over 3 years old it will need a new battery Make an appointment at Apple store For checking.

Or contact Support.apple.com for posting details.

Cheers

Brian 🇬-1F1E7;

I have the exact same problem after the iOS 11 update, both my iPhone 5S and my iPad mini 3 have issues with intermittently accepting charge after the software update. Apple has broken something in their update and they need to fix this ASAP!

I need to plug in the charger and check that the battery percentage actually goes up before leaving it to charge. Otherwise I need to unplug the charger and try again until it accepts charge.

And before anyone states the obvious yes its the original Apple chargera and cables that worked flawlessly before the software updates that gives the exact same issues on hardware of the same generation. This is a software bug plain and simple.

He has apple care, so its unlikely his battery is more than 3 years old. And old battery would not work "sometimes".