This article describes how to troubleshoot battery issues on the TC-100.
If the battery is not getting detected by the TC-100 and shows an (x) in the battery icon (as shown below)
while the wall charger is connected then its possible the TC-100 might have outdated firmware/OS. Follow the steps below to correct this issue. 
NOTE: This affects newer batteries that were recently purchased as a replacement for older TC-100s.
Install latest firmware/OS on the TC-100.
NOTE: Plug external power to the TC-100, remove USB flash drives, and close any running programs before installing firmware.
- Click the Start button on the bottom right corner and then launch the Device Info app.
- Note the Original OS Version, Patch OS version, Bios Version, and Embedded Controller version.
- If you have BIOS 1.48, Embedded Controller 1.29 or newer, and OS Version 23107 (or Patch OS Version) or newer, then you do not need to update your TC-100 controller.
- If either of those OS versions is 22039 or newer, then proceed to next step (7). Otherwise install OS 22039 first from the following file:
- OS Patch 22039.exe Follow onscreen instructions.
- Install latest BIOS 1.48 and Embedded Controller 1.29 to the TC-100 by running the following file:
- Install latest OS (23107) to the TC-100 by running the following file:
- Battery might get updated as well. If spare batteries are available just swap them to the TC-100 for them to get updated. Just make sure the wall charger is connected to the TC-100.
- Battery should now be detected by the TC-100.
NOTE: you will need to move the OS and firmware files to the TC-100 via a USB flash drive and then run them from the TC-100 and not from the USB flash drive.
If battery is still not detected after following the steps above check the following article for more troubleshooting steps:
TC-100 - Battery Power Troubleshooting
If the battery is not getting detected after follow the article above then the battery is most likely defective and will need to be replaced.