Jump starting cars with flat a battery

Check the vehicle operating manual. If there are no specific instructions, then follow the steps below. If the failed battery is open circuit*, then do not attempt to jump start. If your vehicle is fitted with electronic components, ensure that a set of surge protected jumper leads are to be used.

*Open circuit batteries can be detected by:

Battery volts reading zero immediately a high rate discharge test is applied
When the battery will not accept a charge.
Also battery that are dead flat or very low

Step 2

Be sure the batteries of both vehicles are the same voltage (6 or 12 volt)
Drive the donor vehicle close to the disabled vehicle, but ensure that the vehicles do not touch
Place both vehicles in neutral (or park) and apply the handbrake
Make sure that both vehicle ignitions are switched off and all electrical equipment (radios, fans, etc) are switched off

Step 3—Negative Earth Vehicles Only

Connect the vehicles in the following exact sequence. Make sure the jumper leads are clear of any moving parts.

Take the RED jumper lead and connect it to the POSITIVE terminal (marked + or POS) of the discharged battery
Connect the other end of the RED jumper lead to the POSITIVE terminal of the donor battery
Take the BLACK jumper lead and connect one end to the NEGATIVE terminal (marked – or NEG) of the donor battery
Make the final connection to the engine block or chassis of the vehicle with the flat battery

Step 4

Start the donor vehicle (with the good battery), then start the vehicle with the flat battery.

Step 5

After starting, allow both engines to idle for about five to eight minutes before disconnecting the jumper leads (to allow both cars’ electrical systems to balance). This reduces the possibility of damage to vehicle electronics.

Then turn both car engines off.

Step 6

Remove the BLACK cable first from the engine block of vehicle chassis with the flat battery

Then start the car with the flat battery to make sure it has accepted a charge.

Remove the opposite end from the donor battery
Repeat for the RED cable

Step 7

After your vehicle has been jump started, providing the battery is serviceable, it will only have a surface charge. This surface charge may successfully continue to operate the vehicle for the rest of the day, but may well dissipate overnight, presenting another flat battery the following morning.

It is recommended that the battery be fully recharged by using a battery charger at the earliest opportunity.

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