iPad 3 not charging after battery replacement.

Customer brought in this iPad 3, indicating that it wasn't charging properly. After testing the device, I found that it would only charge when turned off, but it'd only charge up to 38%. I removed the Digitizer and LCD and swapped out the charge port with a brand new OEM, ordered from etradesupply, while waiting for a battery to arrive. Device still would not charge, neither would the battery indicator show up when plugged in, nor would my laptop recognize that it was plugged in (we have 6 laptops and 3 desktops in our store, and I've plugged the iPad into all of them with the same results); but still charged when powered off, but still only to 38%. I then replaced the battery, OEM, also purchased from etradesupply. The battery was actually new (all iPad batteries that I've ordered in new were in fact used, and you can observe this on the bottom of the battery -- pressure creases where the adhesive is set, indicating the battery had been pried out of another iPad), and tested fine on the multimeter. The device turned on right when I plugged the iPad into a USB cable, connected to my laptop. I let the iPad boot up, then noticed that there wasn't a lightening bolt going through the battery indicator on the top of the screen. I left the iPad plugged in for a while to see what would happen, and it dropped from 55% to 27% less than 2 hours. My laptop (and all other computers) still doesn't indicate that the iPad is plugged in. iPad still charges when turned off, but only to 38%. I then tried a couple different charge ports, and the computer recognized that a device was connected, but it showed as an unrecognized device; still, the battery kept discharging; I then tried several different cables, did power home resets, but still had same results. The device is on IOS 7.04. I haven't tried factory resetting it because the customer is afraid that they don't have it backed up on their computer. I asked the customer if this problem occurred after their most recent update, but they were uncertain. I removed the replacement battery and installed it into a different iPad 3, and it charged up to 100%. Has else ever experienced this? Anyone experience this and found a solution?