Love this solar keyboard, (hate that there's no CAPS Lock button and the on screen one stopped working a few months back--that's another issue for another day). HOWEVER, the keyboard sure died a slow death fast. Have only had this for about a year. I replaced an older one that stopped working with this one. Thankfully that was a Costco return/exchange and didn't cost me anything, but it apparently WAS the same problem now as before...dead or not properly charging battery. I internet searched for troubleshooting and found this site. Can't believe Logitech's site says "battery is not replaceable." What a line of garbage! Thank you sooooo much for knowing and sharing this.
The only thing that caused delay in repair was FINDING the battery, but alas, with your great identification of the exact battery and good ole, reliable Amazon, there it was...with Prime Shipping I got it 2 days later, just now, (that's why I said it takes 2 days to fix--otherwise it's only 30 seconds or less once you have the battery.) It was easy as pie and already I am back up and running with my favorite clicky keyboard. Now if I can only figure out this CAPS lock thing...but alas I will try your site again to see if you have any advice on THAT next!
Getting the battery tray out WAS a little challenging, but not really. I did what the others said, starting from the TOP of the keyboard facing up and used a regular knife (I know, I know) and though the tray's a little marked up now, it was totally worth the $6.50 I spent to make this repair..Thank you. Thank you.