unknown electrical issue

[Tom Line]

Originally Posted by audietron

We are having an issue with our robot working great for about a minute before the battery starts to drain rapidly. It continues to drop to about 11 volts at around 3 minutes of hard defense before it starts to jitter like seen in this video.

http://youtu.be/_hXEWTRuxOU

Also shown in the video is that nothing else is able to be controlled while it is happening. The motor controllers run green yellow red rapidly when this is occurring. We have changed out the breakers and checked all the wiring connections and are still not able to figure it out.

Any help would be appreciated.

You are drawing enough current when you are trying to turn that you are dropping the battery voltage to the point where you are browning out. 3 minutes of hard defense might very well do it, especially if you scrub when you turn your drive train and spend a time pushing without spinning your wheels (stalled).

Make sure you don't have any mechanical binding in your drivetrain, make sure your gears are greased, sprockets / belts aligned and tensioned, and all your bearings are good. Double check you've got drive from each one of your motors individually (just pull breakers one at a time to make sure all your drivetrain cims are working). One way or another, if you're starting with a fully charged battery you're draining it quickly.

We found with the Andy-Mark kitbot wheels the center wheel wore fast enough that by the end of a competition all 6 wheels were rubbing the carpet at once causing a lot of scrub when we turned.