Why does my iPhone 5 kill batteries?

I have an Iphone 5 that stopped working one day with the battery at ~94% (been working fine for 2+ years). I would get the flashing apple logo when plugged in. Did the reset trick but could never get the phone to operate at all unless plugged in. I replaced the battery with a brand new one (cheap ebay) and it worked fine for about 2 days, then the new battery died the same way. I then bought a genuine apple battery thinking it was a cheap battery issue, but this third battery died the same way (2-3 days later). Last night i tried failed batteries in my wife's IPhone, and her phone would not work with them (flashing apple logo). Drawing the conclusion that my IPhone is killing batteries. I have another genuine battery, but I am scared to install it. Could this be the U2 IC issue? I keep reading that it should only fail if your battery drains and in both cases my battery was nearly fully charged.

BTW, I threw away my generic chargers and charge cable after the first battery failure. I have 3 other IPhone 5s sharing the same remaining chargers and cables. My phone is the only one freaking out.

Any help would be greatly appreciated.