Battery would not charge, replaced it, new one wont charge?

I have this same problem. It is not the connector, as it shows it's charging (charge light turns on), and when it was plugged in all night, it "charged" to 0%, but the phone stayed on, showing me that it receives power through the cable. It's not the battery, as I checked the battery's health and even bought a new one, and saw the same problems.

It also occasionally charges, but usually not above 70%, and it doesn't consistently charge to the same level. It also doesn't actually charge each time it's plugged in, and there seems to be no pattern over 5 days of when it decides to charge other than that if it is charging, and is disconnected, when plugged back in it will not charge again.

It's a weird issue. Anybody seen this before? I'm guessing its a software/firmware problem, because it's actually getting power.

I chatted with some of the EEs in my office, and we decided that probably the charging circuit in the phone is shot. This means that I will need to charge it externally, so I'll be able to charge it. As far as I know, there is no way to fix this.