Replaced battery, still having fast drain

"If you use a known good battery and still get this fast discharge, then consider the following:

First possibility is that you a have a short somewhere on the board, causing battery to be depleted because this short is consuming power and dissipating heat.

And also the charging circuit in the iPhone 5 is infamous because of a component on the board known as U2 which often fails. The risk of breakdown increases with the use of bad quality charging cables and car or wall chargers.

There are 2 major symptoms that I know of, that indicate the failure of this component:

A/ The phone will charge *seemingly* normally, but if ever it shuts off, it won't turn back on. Change the battery, and it will work normally until again it shuts off. Then again it won't restart. Chronic.

B/ The battery will discharge very quickly and will be dead within 1-2 hours!

C/ Device will not communicate with computer via USB. As if never plugged. And/or you get fake charging (says it is charging but does not).

I don't know how much it costs to fix this in Europe or the USA, but it should be pricey because of the required special tools, skills, and experience.

My advice is to take it to a reputed and trustworthy repair shop that can test the device, confirm the prognostic (may be you're lucky and it is something different and easier to fix), and quote you the repair.

OR have it exchanged at the Apple Store by paying an exchange fee, if still possible (as you already worked on it, they may refuse to do it)."

Unfortunately this is happening to a lot of people and no1 has the answer it could be prying damage on motherboard any1 else no component damage in the motherboard that would cause this?

For starters never restore it as new as I've seen people on forums suggest. That deactivates it from the carrier and then you have to reactivate your number and everything secondly have you done a hard reset while it was plugged in? Because they could have messed up the sensor that reads have much power is left. Thirdly check your usb cord if its falty it could mess up your phone's ability to hold a charge. Take it to an Apple Store though instead of listening to forums though

i bought a iphone 6 battery pack from fixjeiphone it after doing it correct the battery still drains fast and its running slow i cant even play some apps i have tried to fully restore it and delete everything its still very slow i need this phone for school