Chosen Solution
Hi, I swapped the original battery in my 2014 MacBook Pro with a new one from iFixit. I worked fine for a few months and then all of a sudden it started draining extremely quickly (like 100% to 5% in ten minutes). When it gets to 5% remaining it stops there for a few hours with very light usage. If the monitor enters sleep mode it doesn’t wake up if you don’t plug the charger in (even after 10 minutes since the last charge). I checked the battery status on CoconutBattery and it shows only 3% on design capacity (!)
I’m suspecting you have a bad battery here and will need to contact the iFixit store to get a replacement Contact iFixit Customer Support