I have a Fenix 5s, but the forum for that is now archived, hopefully it's not too different to the 6 for charging.
I hadn't worn it for a few months, put it on charge, it charged to full after a couple of days. I wrote it for just over a week, charging it a couple of times when it was getting low, it charged to full in about an hour. It turned it's self off while I was wearing it last week (it was ~20% battery the last time I looked, some time later is had turned off).
It is now showing me the 0% battery symbol, with the lightning sign and a small red bar. I've left it on charge for a few days, and it is still showing the same. I've tried pressing various buttons. The light button turns out off when it's on charge but does nothing when it's unplugged. I've tried a couple of different charges, wall sockets, PC. The PC isn't recognising it as plugged in so Garmin Express does nothing on the PC. Not showing as needing an update, but it also says not connected.
It's it dead? Can I replace the battery? Any tricks to get it charging again?
Thanks,
I emailed Garmin support on Sunday, but still waiting for a reply.