Chosen Solution
I recently purchased a replacement battery from IFixit and after replacing the old battery I noticed that the new battery was struggling to charge and the magsafe adaptor was frequently changing from green to amber. I reset the SMC without success and re-installed the old battery which was charging at a normal rate. Update (03/05/2019) Coconut Battery
It appears your battery is OK, but the charger and or charging logic has a problem. Review this Apple T/N https://support.apple.com/en-us/HT203207 Make sure you have the correct charger, as well as the cable and MagSafe connectors are in good shape. Also make sure you get a real Apple charger as many fakes are out there! OEM MagSafe Chargers vs Cheap Imposters: Teardown for Truth Monitor CoconutBatteries bottom entry Power Adapter should change to ‘Connected’
