Update 2018 Dec.: I have an iphone 6S now, bought it for $60 as it wouldn’t turn on, having broken the screen of a newer 6S I traded from Kijiji. This Gold 6S, upon opening had signs of water damage both on top by camera and bottom at charge port area but no significant damage. Fortunately I had parts and could interchange that logic board and anything else. Cleaning the charge port itself (after disassembling the whole phone realizing the logic board wasn’t water damaged) I was able to get the phone working but the power drain was very heavy and the phone would reboot itself or shut off intermittently! There was no physical damage to the charge port electronics but inside the port itself where the contacts are there was an issue and I had to connect and disconnect it many times before it would take a charge at all and at first sat there for several hours only to get to 75%… Sometimes my phone would crash an then when it turned back on it would show Red 1% power then it would jump right back to 100 % or close to that! Everytime it said around 1% when rebooted.
So, Changing the Charge Port itself made this phone work perfectly and now battery life is Superb, charges properly and by the way there was a new replacement OEM battery in this phone when I bought it and the charge port itself was depleting it severely and causing crashes, and long periods before it would reboot and lengthy boots.
Jump+ tested this phone just prior to me purchasing it and claimed it as a logic board issue and the repair would cost owner $280.00 Canadian.
I had this phone booted in 15 mins and original owners were upset at Jump+ because they wanted their pics. Again I prove that Apple only wants to replace logic boards (worth more than phone itself) and they have no Jump+ staff trained properly enough to resolve peoples issues with iDevices. Unless you are under warranty I would take nothing to Jump+, Staples, Best Buy or anywhere that doesn’t get into actually testing the logic boards themselves with other known working parts! I have gotten Macbook Pro’s working easily that were deemed Logic board Issues yet turned out to be Track Pad and or Keyboard issue and sometimes a simple thing like a ribbon had water damage. Of course I clean logic boards and inspect things very closely. Most times there are visual clues that aid in resolving these issues.
Hope this helps.