I have been editing using lightroom 6 on my PC for several years now and have noticed in recent months that every time I'm editing without my computer plugged into the charger, it dies almost instantly. This only occurs when I'm using lightroom. I am not sure if I need to delete a bunch of old folders or what I would do to solve this issue. Any suggestions are greatly appreciated!
Laptop batteries eventually fail over time. 2,3,4 years or so. What you are describing sounds like that. Check with the manufacturer for a replacement battery. You can probably find a video on Youtube showing how to do the job yourself.
You probably notice it happens sooner because of the way LR uses the processor, hard drive, etc.