Chosen Solution
My MBP suddenly stopped working on battery. The battery is 98% charged and the computer runs normally on AC but as soon I unplug the power cord it dies. There has not been any mishandling or water issues nor anything happened. Just all of a sudden it stoped runing from the battery. model: Apple MacBook Pro “Core i5” 2.5 13" Mid-2012
For power related problems, I would consider an SMC reset. Reset the System Management Controller (SMC) on your Mac
