My daughter in London just had this same issue with her 2010 MacBook Pro. This is what I told her based on some online research on the issue. She did the calibration and that fixed her problem.
Possible Causes and Solutions
Here are some possible causes and solutions. A faulty battery is probably NOT the problem. I suggest that you try each cause/solution in the order shown.
Do the following:
- Charge it to 100%, and keep charging it for at least two more hours.
- Unplug your laptop and use it normally to drain the battery.
- Save your work when you see the low battery warning.
- Keep your laptop on until it goes to sleep due to low battery.
- Leave it overnight
- Charge your laptop uninterrupted to 100%
Some people suggest that repeating the calibration process for a second time solved their problem and increased the measured battery capacity
Try resetting your System Management Controller (SMC), which is a hardware chip that controls some hardware settings, including the power system. The process is straightforward, but any customisations to your power plans or hardware settings may also be reset.
Here’s how to reset the SMC:
- Shut down your MacBook Pro
- Press left [Shift]+[Ctrl]+[Option]+the power button at the same time and hold for 10 seconds
- Release all keys at the same time.
- Turn on the laptop.
The SMC controls the computer fans, backlights, and indicator lights, as well as some aspects of the display, ports, and battery, so resetting it will force your MacBook to revert back to its default settings for all these things. I
If a transient issue in the SMC was causing the Service Battery warning, this should address it
(Extracted from https://www.techjunkie.com/service-battery-mac-replace/)
Some users found the problem was caused by a dodgy cable between the charger and Mac. It includes both power wiring and monitoring wiring. The latter feed the battery status back to the charger. If one or more of the monitoring wires are not connecting, the control of the charging process does not work correctly. Check for cable damage at each end.