I have purchased a used iPhone SE on eBay. Phone is in good shape, however I noticed the battery behaved poorly. It would drop percentage pretty quickly during basic tasks like music playback or just idling, during other times it would hold percentage for a while. Also phone would often times get pretty hot during charging which is not normal. I ordered a gently used original iPhone se battery on eBay. When I opened the phone I did see that a third party battery was installed, so I swapped it out with the OEM battery I just purchased. I followed ifixit guide. Afterwards I booted up this phone and at first battery showed 1%, then jumped to 10%. No matter what phone would not charge passed 10%. I opened up coconut battery and it showed max charge of 6% out of original capacity and cycle count and temperature unknown. So I contacted seller and he sent me another battery. I connected the 2nd battery i just received and phone was behaving the same way, except for now it charged to 13%. I decided to connect the original battery this phone came with (3rd party battery), and behold it is also doing the same thing. Charges up to 10 or 15% and that's it. When I go to battery health it says service battery, where as before it showed 98% capacity and was saying that battery was at peak performance. So the original 3rd party battery is now behaving the same as the 2 OEM battery replacement I got from eBay. Original battery was performing poorly but it did charge to 100% and held charge. Also full charge capacity was at 100%. So something happened between me opening up this iPhone and installing multiple batteries. I have reconnected all the ribbon cables, all the brackets are connected. Touch screen, camera, sound, touch ID....everything is working. I can not figure out what is going on. Also when connected to my mac this iPhone reboots every 5 minutes. When connected to apple 5w wall charger phone does not reboot, but does not charge passed 10-15%. Only bracket missing was the one for touch ID ribbon cable, but I do not see how this would effect battery. If anything missing touch id bracket would affect touch id, but it is working just fine. Seems like phone can not read any of the 3 batteries. Anyone have an idea of what's going on?