I recently upgraded my MacBook Pro (mid-2012) HDD to SSD. Once SSD install was complete, my macbook did not start, however when plugged into power, it started booting, and worked normally.
The battery was in decent condition, and was always lasting 3+ hours.
I tried SMC reset, and PRAM reset few times in last few days, however no change in status. On removing the power adapter, it goes to sleep mode.
Very annoying that now onwards, I always have to plug in the power for doing any work.
Any potential hints ...