Balance charging NiMH Robot Packs

[redpoint5]

Originally Posted by 172pilot

I'm curious after a little bit of time, whether the new batteries you ordered did the trick?? I have a "refurb" neato vac, and it's doing the same thing.. It ran for about 60 minutes the first two times, then it started doing it's 5 minute at a time thing.. I upgraded the firmware, because they say it had some battery issues, and then did a "new battery" trick on the Neato, and let it calibrate again, and it worked again TWICE and is now failing again..

I couldn't tell from your pictures - How were the neato's batteries wired? There's a 4 pin plug.. Can I gain any insight, and/or do at least a partial balanced charge through the exposed connector? I have a balancing charger meant for LiPos for an RC airplane that would work fine if so...

I ended up buying new battery packs for the Neato on Amazon. Although my charger showed each cell as having about 80% capacity, I suspect that the cells were damaged and actually had a much lower rating under load. The cells in the Neato are connected in series, and it's not possible to balance charge through the connector. The 2 yellow wires report temperature to the robot for thermal protection.

My Roomba ended up getting a Li-ion battery from this guy, although I bought a slightly used one from his Ebay auction. The Roomba runs much longer now, always finishing a run with plenty of power left. So far, so good.

I now have an RC charger capable of balance charging/discharging multiple chemistries and voltages. I'll update this topic in the future when I get back to tinkering with restoring pack health. The truth is, I hardly ever run the robots anymore now that I'm married. Somehow the floors are magically cleaned when I'm away at work. I've also got a refrigerator that stocks itself with groceries.