Uncommon issue with tg0b error - Rebooting every 180 second

I’m having a very weird issue after replacing the dock connector for the original prs0 failure on the dock. The original battery isn’t detected and shows no percentage. This causes the phone to boot every 180 seconds. So I bought a new battery from a reputable company and it worked for around an hour. Then when I put the phone back together and rebooted the battery is back to the original batteries situation (no percentage and reboot every 180 seconds) I’m not sure what’s causing this to happen to the batteries. I don’t think it’s a board issue because a new battery solves it. I have bought a new battery for further testing.