Extending the run time for DFRobot 4 wheel platform and the Tamiya Tracked Chassis with two gear motor.
DFRobot: replace the 5 AA battery holder with two 2-C cell battery holders wired in series. This gives 6 volts, but approximately 4 times the current. Of course, it is double the weight of the other holder, but the DFRobot four motors are able to handle the little extra weight and give more run time.
Tamiya Gear Motors: To get more run time here use two 2-AA battery holders wired in parallel. My robot runs with ease and has shown no signs of fatigue after more than 30 minutes of use on carpet and smooth surfaces.
I had my robot working for a while then the motors would suddenly stop. Resetting the controller would have them work only for a few seconds before shutting down again. When this happens the controller LEDs will go out. I have researched this on the web and it seems the Pololu Low Voltage Dual Serial Motor controller has this problem. Many people have added capacitors across the motors as I have as well. It seems to be a complex problem and no one is really sure what causes it. Noise, overheating, low current, too much current all have been explored. I will continue to play with it and report back if there are any successful developments.
