If you find yourself in a situation where the chassis battery is dead, before attempting a jump-start, first look to see if the motor home is equipped with a Battery Boost Switch.  The battery boost system taps into the house batteries for power to jump-start the chassis battery.

To operate battery boost, turn the ignition off and press down on the Battery Boost Switch for a count of ten.  Continue to hold the switch down and attempt to start the ignition.  If the engine fails to start, release the Battery Boost, turn the ignition off and engage the generator.  After thirty minutes of generator operation, hold down the Battery Boost and once again turn the ignition on.  If the engine fails to start, halt any further Battery Boost attempts.

An external battery charger is the preferred method to charging the chassis battery.  If one is not available and you decide to jump-start the chassis battery, proceed with caution.

Never jump-start a battery with a shorted cell.  A shorted cell will place heavy current load on the source battery as it tries to charge the damaged battery.  Use a battery hydrometer or digital voltmeter to check liquid lead acid chassis battery cells.  A digital voltmeter can check discharged battery voltage.  If you see a reading around 10.00 Volts or less, this usually indicates the presence of a shorted cell.  If the chassis battery shows evidence of a shorted cell, you will need to buy a new battery.

Recreational vehicles today include specialized electronics.  When battery cables are connected, circuits inside these electronics power up and down, generating sparks and arcing.  This can create spikes of up to 105-Volts.  Voltage spikes send a shock wave, commonly called a surge, to computers and electrical boards.  Electric panels, the automatic transmission, circuit boards and electronic engine controls are extremely vulnerable to high heat and high voltage.  Excess voltage can also cause irreversible damage to multiplex systems and the solar panel charge controller.

Jump-starting the motor home should be used as a last resort.  Jump-start from batteries or electrical systems rated no greater than 12-Volts.  Use a set of quality jumper cables with rubber intact and cable ends clean of grease and grime.  Wear eye protection and heavy gloves.

Park the source close enough to the motor home to leave slack in the cables.  Cables stretched tight can fall off if bumped or unclip from the battery post when ignition vibrates the engine.  Turn off the source while hooking up battery cables.  Take your time to avoid connecting cables in reverse polarity.  Connect the battery cables Positive to Positive and Negative to Negative.  Always connect the ground, or black lead, last.

Golf carts are a preferred method of travel in many campground and motor coach resort situations, but golf cart batteries and their electrical systems are not an acceptable source to jump-start the motor home.  Golf cart electrical systems range from 24 to 48 Volts, far too much voltage for sensitive electronics within the RV.  A golf cart should never be used to jump-start the motor home or a tow vehicle.