How to Jump Start a 24-Volt Vehicle

Find someone with a 24-volt system in their car or truck to come help you. Their electrical system can safely be connected to yours with jumper cables without risking an overload as your vehicle starts.

Move the second vehicle's hood as close as possible to yours, and pop both hoods open.

Look under both hoods to locate the batteries. They are large, rectangular plastic boxes with two large electrical contacts on them.

Clip the red (positive) jumper cable onto the positive ("+") terminal of the battery of the good car, and clip the other end onto the positive terminal of the dead car's battery. If the cars have two batteries, they will be wired in sequence, so it doesn't matter which terminal you attach it to; the good battery will power up the whole circuit.

Clip one end of the black (negative) cable to the negative ("-") contact of the good car's battery and the other end to an unpainted (and ideally shiny) piece of metal on the frame of the dead car. Exposed bolts in the engine compartment work well. Don't clip it to the dead battery itself, as this risks a battery explosion. You may see a spark when you make the final connection; this is normal.

Put the key into the good car's ignition, and start it. Step on the gas with the car in neutral to rev the engine, and provide extra power to the alternator; this will keep electricity flowing into the battery as it charges the dead battery in the other car.

Shut down the good car's engine, and try to start the dead car. This avoids the risk of damage to the first car's electrical systems from the surge in the circuit as the first car starts up, but might not always work. If it doesn't, try starting the dead car with the good car's engine running.

Check for problems if the dead car still doesn't start. All the electrical systems in it (lights, heating, A/C) need to be off, and the terminals of the battery should be clean. If, after wiping the terminals and turning everything off, the car still doesn't start, then it is likely a problem with your starter or alternator, and you will need a tow.

Remove the jumper cables in the reverse order that you put them on.

Buy a 24-volt battery pack from an automotive store, and plug it in to charge it.

Pop the hood of your vehicle, and connect the red and black cables in the same way as you would with another vehicle; red to the positive ("+") terminal on the battery and black to an exposed piece of the vehicle's frame.

Turn the battery pack on and try to start your vehicle. If it doesn't start, the troubleshooting process is the same -- check that electrical systems are off and the terminals are clean before calling a tow truck.