My phone only charges when its off

Before you replace anything, try this Use a toothpick to clean out your iPhone. It might fix your problem.

"Please check your serial number here to see if it qualifies for the Battery Replacement Program:

https://ssl.apple.com/support/iphone5-ba..."

"Dear All,

Fault can be occur due to bad battery for faulty charging IC

Beging trubleshoot with battery replacement,

Here you can find the battery replacement guide."

I was having the same problem with my iPhone 7. I have had the phone since October pf 2016, and yesterday it stopped charging completely. I turned my phone off and let it charge last night so that it could come all the way up to 100%. I just went into my settings and reset the Network Settings back to default, and it appeared to fix the problem for me. Not saying it will do so for you, but it might. I had even went and bought a new charger. But it didn't charge my phone and would charge my moms. So I knew then it had to be something with my phone. After researching a little, I seen that resetting the network settings back to default could be a trick to fix it and sure enough, it was. Good luck with you.

"Son's cell did this same thing. Read through all the ""didn't work"" solutions which didn't for me either.

However, on a goof while it was hovering at 2%, I decided to get into Settings--General--Reset--Reset All Settings. Of course it died mid-reset, but after it came back on & finished, I unplugged & replugged it in while it was still on & it started charging while powered on!"