My iPhone has charging issues after housing replacement.

I have recently gained a new hobby of fixing then selling phones. I've never encountered an issue like this before, after the replacement of the housing(I also replaced the battery), I plugged it in. It showed the charging screen but when it finally boots on the battery symbol near the top right does not show it's charging. It dies shortly after. I do not have any tools to check the amps or to see if it takes power.