Step 17: Camera voltage regulator
Its basically a 9V voltage regulator, a support capacitor, and two diodes. I designed it so that I can hook both the 24V battery up to it as well as the solar backup system. If the 24V battery dies or the robot loses power the camera will automatically switch over to the solar power so I can see where it is.
I added this ultimate paint schematic to show the circuit. Since the power supplies (24v battery and 12v solar) share common ground and are not wired in series you won't ever see 36V. The nature of diodes means only the side with the highest voltage (normally the battery) will pass through. If the 24V drops below 12V (really really dead) or gets shut off somehow then the 12V solar will pass through its diode and the circuit remains powered.