Help troubleshooting 5C Power Drain

OK…here’s what I have done so far:
1. Replaced the battery (tested on another IPhone with no issue).
2. Changed the U2 IC, and reset the phone.

First issue: Battery only charges up to 98% (think that is bad IC on the battery itself, since it’s not OEM, and not a big issue).

Big Issue:
Phone in standby: no battery drain
Phone in airplane mode, with screen active, and proximity sensor/front camera not attached: This used 15% of the battery in .5 hours, while another working IPhone used only 5%.

Any ideas what I should check next? I am now running a test without the dock connector attached, but I don’t think that is the issue.

I’ve searched for other reasons for power drain, but most threads lead to the U2 IC being bad (maybe I didn’t get in on correctly, but I would have thought that if I didn’t I would have had other more serious issues).

I also ran into a thread that mentioned changing the LCD. I "borrowed" my daughter’s LCD for the test, which yielded the same results.

Thanks in advance…Eric