T800 bluetooth keyboard case not charging

[LouiseJ1]

Hi there. My bluetooth keyboard works fine with a usb but appears to be dead without it despite charging for hours. I wonder if it needs a new battery but cannot open it to see what type of battery it uses. Any help much appreciated. Thank you.

[rlaxar]

I have the same problem. I was able to open the case without breaking it and determined that the battery is a lithium/polymer battery with the number 302248 and 3.7V printed on it. The original battery has some other printing that is illegible. The original battery has three leads (red/black/white) from a miniature PCB to soldered to three spots on the main keyboard PCB.

I found a battery with the same voltage and external dimensions on Amazon for about $6:
https://www.amazon.com/gp/product/B07BTHK8TR/
However, this battery has two leads (red/black) from an attached miniature PCB to a two-conductor connector.

I'm guessing that the original miniature PCB had some additional function that is not present in the PCB board on the Amazon battery.

Both of the miniature PCBs are attached by two soldered/(spot welded?) tabs to two tabs on the batteries, presumably plus and minus current. I removed the three-lead PCB from the old battery and patched its two tabs directly to the two tabs on the new battery. The blue LED light on the keyboard briefly lit up but the keyboard did not pair with the tablet bluetooth. Not knowing if the new battery came sufficiently charged, I then plugged the keyboard into a USB charger for several hours to see if it would charge the new battery. Again, the blue light came on and I was unable to make a bluetooth connection.

At this point I am out of ideas. I have not found  a direct replacement for the OEM battery with three conductors.

You mentioned that your keyboard works with a USB connection. I presume that this is with the keyboard connected to a USB charger, which is not convenient? I wonder if it is possible to provide power to the keyboard USB port directly from the USB port on the tablet using a short double-end microUSB cable like this:
https://www.amazon.com/CableCreation-Micro-Compatible-Android-Tablet/dp/B01M5GZ3N0/
Carrying and connecting a short cable like this would be a minor inconvenience.

Your thoughts?