I have read that the input voltage limit for the GoPiGo is 12V: http://www.dexterindustries.com/GoPiGo/learning/technical-specifications-for-the-gopigo-raspberry-pi-robotics-kit/
However, looking at the circuit schematics for the power supply I see that it is using the LM2576, which is rated to 40 V max input. The motor driver, SN754410, also uses Vcc and permits up to 36 V on the input.
What is the reason for stating that the max on the GoPiGo is 12 V? Is it to do with the battery measurement circuit? Is it due to VREAD on the Battery Measurement circuit, which feeds to pin 23 on the ATMEGA? I calculate that at 12 V, VREAD would be 4.8 V, so I’m guessing that’s the reason you give the 12 V limit. Is that it?