After installing the battery and letting it charge for 20 minutes, it would repeatedly indicate "Charging error 1" on my Roomba 655. After a bit of research I fixed it by cleaning the charging contacts on the home base / docking station and on the bottom of the Roomba using steel wool and dry cloth. I also made sure the contacts on the battery were clean (with dry cloth).This battery probably draws a bit more current from the charger than the Ni-MH batteries, which I expect leaves it more susceptible to failure codes on dirty charging contacts.It's on its first charge and I'm letting it run through a full cleaning cycle in each room. It's been going for 4 hours now. What an awesome upgrade (assuming it lasts the advertised 1000 charge cycles).