Chosen Solution
Replacing the battery was no small task but went well. I followed the directions of letting the battery discharge, then charge to 100% then discharge and charge to 100% again, then continue with normal use. However, that normal use will get me to 25% remaining life and then the laptop will shut itself down. I have reset both the SMC and the NVRAM. Laptop seems to function fine other than that.
Return the battery, it is faulty if you have tried resetting the SMC and NVRAM.
OK, I just got a new battery from ifixit and got the same problem but it was turning off at 30%.. I was able to solve it by cycling the battery. Is annoying but it works: -Fully charge the battery and leave it connected and charged overnight. -Then use the laptop until it runs out and turns off by itself. Leave it discharged for about 4-5 hours or more. -To verify if the trick works, pressthe Power button and make sure you see the “Connect to the power” symbol. -Then fully charge it again. After cycling my battery capacity dropped a bit, but at least now is accurate. I recommend doing coconut battery monitor.
