I cut apart a KR808 CE2 carto and made up a charging connector for the ego to my hobby batt charger. Checked polarity by sucking on the tube and it is center positive. I then plugged it into my hobby charger and set it for .1a (100ma for testing purposes). Doesn't work, the smart circuitry in both argue with each other. The charger checks for voltage and stops before the mosfet in the batt opens the circuit to the battery. I get two quick blinks from the battery, then low voltage error on the charger. Looks like this will not be the solution.
I think I can force the mosfet open by putting an 18650 Li-Ion in parallel with the charging circuit, but I will need to isolate the batteries from each other. If not isolated, they will try to quickly balance themselves and I could let the smoke out of the whole thing. I'll keep those interested posted.
-Flip