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Dead battery? Be careful your jumpstart isn’t going to make matters worse

How To Jump Start A Car Correctly

If you are feeling the bite of winter and that you need a jumpstart from bed in the mornings, your car battery could be feeling pretty much the same.

It’s no secret that cold temperatures affect car batteries but other factors also play a role in why you may need to jumpstart your car. Be aware though, says the Motor Industry Workshop Association (MIWA), a proud association of the Retail Motor Industry Organisation (RMI), a well-meaning jumpstart could be costly if not done correctly.

MIWA chairperson, Dewald Ranft, says while the jumpstarting procedure is relatively standard for all vehicles on the road today, jumpstarting can cause serious damage to the vehicle’s electrical system and computer if done carelessly or incorrectly.

“The most common reason a car might need to be jumpstarted is a weak or dead battery, especially in winter. Other problems can include malfunctions in the starter or alternator, dirty spark plugs and clogged fuel lines,” he says.

“In winter, cold weather makes your battery work harder. Simply put, the battery needs to produce a certain amount of energy to activate the starter motor and crank the engine. With the rate of reaction in batteries slowed by cold temperatures, the starter motor needs a much higher capacity to successfully crank the engine.”

Another factor, Ranft adds, is that cold weather can slow down the recharge rate of your battery, which means the alternator requires more time to charge it. If your battery was already old to begin with, chances are it won’t provide enough capacity to get your car started in the cold.

Chances also are that you are not going to care what the cause of a flat battery is when you’re stranded in your driveway and have to do your important meeting via Zoom from the front seat of your car.

If you have jumper cables, Ranft says these are the important do’s and don’ts of jumpstarting a car:


  • Read the owner’s manual. Check the car’s manual for any specific instructions and to ensure that the various locations are identified for the jump-start terminals in your car. In many modern cars these terminals are placed at strategic places in the vehicle due to the battery being in a hard-to-reach place.
  • Verify the voltage of the battery in the vehicle doing the jumping. If they do not match, serious damage can occur to both vehicles.
  • Park the cars close enough for the cables to reach, but they should not touch.
  • Turn the engine off in the car with the good battery.
  • Unplug any accessories (like cellphone chargers); the power surge generated by the jumpstart can short them out.
  • Park both cars in neutral with the handbrake up.
  • Turn off headlights, radio and indicators (including hazard lights) in both vehicles.
  • Put on rubber gloves and safety goggles before starting the procedure.


  • Lean over the battery of either car.
  • Smoke while jumpstarting a car.
  • Jumpstart a battery if fluids are frozen. This could lead to an explosion.
  • Jumpstart a battery that is cracked or leaking. It could lead to an explosion.

“More than 300 volts goes through your system when the two batteries are connected. To prevent equipment being destroyed, make sure all headlights, indicators, radios and air-conditioners are off and cellphones and other devices are unplugged,” Ranft says.

“There are many things that can go wrong with a battery or affect its lifespan. This is why it is important to ensure your car receives a full battery check as part of your scheduled services at an accredited workshop.

“If you are not sure about how to jumpstart your car, follow the tips we have provided or talk to the experts at your workshop. It is better to be safe than sorry as incorrect jumpstarting could end up being the start of big problems for your car.”

The MIWA 5-step jumpstart guide:

1. Connect one positive (red) end of the jumper cable to the positive (red) terminal of the dead battery.

2. Connect the other positive end of the jumper cable to the positive terminal of the good battery.

3. Connect the negative (black) end of the jumper cable to the negative (black) terminal of the good battery.

4. Connect the other negative end of the jumper cable to a shiny nut or bolt on the uncharged vehicle. This will need to be a grounded piece of the engine or the frame of the vehicle. You should only connect to the negative terminal on the dead battery as a last resort to avoid an explosion by spark.

5. Once the car batteries are linked, let the host car run for a minute or two before attempting to start the uncharged vehicle. Once the vehicle starts, remove the cables in the reverse order to that you connected them.’

Eugene Ranft 1
MIWA chairperson - Dewald Ranft