New Battery: Runs out at "10% left"
If a new battery doesn’t work with your hardware - I would return it to the vendor or seek service. Some aftermarket batteries may not work properly and the failure you describe isn’t likely to be something you (or any technician) messed up with cabling or connectors not seated.

When you reset the SMC it perhaps did a full read of the battery details and something isn’t correct for it’s code to predict when to send the low voltage / low charge warnings and begin an orderly shutdown.

This failure mode is different than the shutting off too high a remaining change - but it could be the same fix - get another battery.


Battery on white MacBook shuts off abruptly after 30% charge is left