Yeah mine died at about 42% :\. Looks like I'm popping this sucker open to reseat the battery.
Alright so I completed the process of taking the switch apart and then reseating the battery after waiting 30 seconds (Holding power the whole time). I wanted to bring some suggestions/traps I fell in to here:
1. SDCard reader: DO NOT have an SDCard in the reader when you are reseating it, to put the console back together, if you accidentally hit the wrong pins you will brick your SDCard (not the console). My pro tip here is to remove the foam on the back of the plug for the SDCard reader to re seat it. Then re apply said foam.
2. Small Screws: The top 2 and bottom 2 screws (I don't think I needed to remove them so shame on me) are really small and really easy to lose, I dropped one, so screw count minus one (I'll be buying spare screws from ebay tomorrow because why not).
3. Be careful: Make sure your console is off etc before doing this, check frequently that the screen is still off as you disassemble as you may accidentally hit the power button which may (even though your batter is "dead") power on the console.
Stay safe kiddos and RIP SDCard and screw.
Oh:
4. Joycon rails: You only have to remove the center screw in the rail (Each Side) to pop the back cover. Don't remove them all (Less screws you might lose).