[Al Skierkiewicz]

Jose,
The circuit I included in my last post is an electronic latching relay and the remote start button can be off board the car and connected through a second connector which is the same as the power connector you described. You can purchase a real latching relay that will not drop out with low voltage but they are more expensive and you must supply power to get them to unlatch. Relays speced at 5 bvolts will pull in at a lower voltage perhaps as low as 4 volts. They will remain pulled in until the specified "drop out voltage" which you will need to look up. These specs vary with design and manufacture. You could also replace the relay with a power MOSFET powered by the fuel cell. An SCR might also work but will have a forward voltage drop that will take away from the motor.