My Macbook Pro 2013 had the same problem. But then I found this free python scripts with explanation: https://www.reddit.com/r/mac/comments/9p... and after some month of terrible problems and an increasing frequency of random shutdowns my mackbook runs the first time without charger and any shutdown. I almost cannot believe it... Now since 20 days it works absolutely well. I can use it as before the problem appeared. Even the weak battery (from permanently charging for a few month) works very well again. I can really recommend this simple solution. Jens