A
battery monitoring script tshring wrote that you can run with his
Kobo Start Menu. If you have it running while you charge your Kobo, you will see charging data updated every minute. The way the charging process works it will get to a point where the number stops increasing, that is as it should be, wait until it jumps to 100and and says "Not Charging". It may take some time between when the number stops increasing and it jumps to 100, that is as expected.
Luck;
Ken