A couple of Bioloid problems

[Bushwhackr]

First is the battery charging. I have only had my Bioloid Comp. kit for a month or so. The battery has charged fine until now. There are 6 NiMH cells of 1.2 volts each for a nominal 9.6 v pack. The other day I was charging it (with the battery inside the CM-5 and right-side up) and I noticed the blinking light began slowly, then eventually got really fast, then started slowing down. At this point I took out the battery and it was HOT!. I mean it was too hot to hold in your hand for more than a few seconds. The voltage was over 11 volts open curcuit. After it cooled, the voltage dropped to 10.5 or so.

I have also looked at the charging voltage by running the robot terminal while it is charging then Dumping one of the Dynamixel data tables and looking at the voltage reported. It is over 12 volts! When I unplug the AC it drops to a more reasonable value.

I am worried now about overcharging the NiMH batteries, having read about the battery recalls, laptop and cell phone fires, etc. Anybody have any thoughts on this?

The second is the humanoid model. It works beautifully, but when it walks it veers somewhat to the left. Anyone have some hints as to how to tweak the offsets or the motion files so it walks in a (reasonably) straight line?

Thanks!

Mike

[limor]

The battery does tend to get hot since it is doing a "quick charge" routine. But too hot to handle doesn't sound quite right.
The exploding battery recalls are related to Lithium batteries. the NiMh are supposed to be quite safe.
Veering to one side may have to do with small construction asymmetry or even difference in foot sole friction.. Maybe if you take and show us a video, someone may have a better idea of what's causing the problem.