My iPhone will not turn on after several hours of charging. HELP?

"When plugged in, do you get the battery symbol come up on your phone?

iPhone 5 has known battery issues. If the phone registers the cable, I would look to replace the battery (genuine Apple replacement only) AND then also restore the iphone via iTunes, and set it up as a new iphone

If it doesn't register the cable being plugged in, try other cables / charging plugs, then look to replace the charging port.

You can get more help at the iPhone Won’t Turn On wiki. Good luck!"

"Heat it up with a hairdryer, it will work

Update (08/25/2017)

--To prevent confusion, this is a reminder that this update was by another person.--

I honestly don't know why this would work, but being that it has helped people, I want to remind everybody: DO NOT HEAT YOUR BATTERY DIRECTLY! This is extremely dangerous. Maybe @philipengel could elaborate more on what he heated and for how long? :)"

In this situation it is always hard to judge exactly where the problem lies. To me, this sounds like a battery failure. You can buy the battery here:

The hairdryer will help for a short peroid of time, to resolve it permanently we need to work a little while longer :)

It is seems that your power supply circuits are fine that means your battery and battery connector are working fine. Battery symbol shown on screen. So display assembly are also fine. Now your iphone wont turn on or not booting up is your problem.