Battery Charging Issues

When I boot my G7 15 7588, I get a system warning "Alert! The AC power adapter wattage and type cannot be determined. The battery may not charge. The system will adjust the performance to match the power available."  The battery definitely is NOT charging. When I run diagnostics from this warning screen, it says no battery is installed and gives <Private data removed from public view. DELL-Admin> Error Code 2000-0131, Validation Code 86414.

I replaced the battery. It came about 20% charged and I no longer got the error message.... until it went dead completely because it still wasn't charging. I replaced the charging adapter port because, well it was loose a bit like they tend to get and a new charging port cost half what a new AC adapter will cost. I've checked all connections and everything seems to be seated as tightly as they can be. Not sure what else to do. I've read that it could be the AC adapter, which falls in line with that system alert message, but it doesn't seem likely to me, and I checked the specs - this appears to be the original AC adapter (I got the computer secondhand) as it is a Dell brand adapter and all specs match perfectly.

What appears to be, is that the replacement battery was fine while it had charge, but now is not detected because it is completely drained. The problem then, since the new battery is doing the same as the old one, is that the problem is not the battery but the charging system. From this, I eliminated the charger port. Correct me if I am wrong, but all that remains then is 1) the cable for connecting the battery and 2) the AC adapter. I suppose it could be a problem on the motherboard but that's not likely is it?

Oh, and super helpful was the Dell Support diagnostic test that says my computer has no issues....

Thanks