Battery Boosting: Not Without Risk

Many a car will refuse to start up in bitterly cold winter weather, leaving owners with no choice but to rely on jumper cables to get out of the situation.  Boosting a car battery may seem like an easy task, while it is in fact quite a delicate operation: one wrong move can damage the vehicle’s electrical components, not to mention that if you fail to follow the procedure to the letter, you could sustain serious injury. 

Boosting technique in 12 steps

1. Pull the running vehicle up close to the dead vehicle making sure the two vehicles are not touching. 

2. Turn off all electric accessories: heater, air conditioner, lights, defroster, etc.

3. Engage the parking brake.

4. Manual transmission: put the gear shift in neutral.
Automatic transmission: shift to “park”.

5. Start the engine of the healthy vehicle.

6. Attach one red booster cable clamp to the positive terminal (+) on the dead battery.

7. Attach the other red cable clamp to the positive terminal (+) on the healthy battery.

8. Attach one black cable clamp to the negative terminal (-) on the healthy battery.

9. Attach the other black cable clamp to the engine block or another major metal component of the engine – like the alternator frame – of the disabled car. 

10. Try to restart the car. If the engine fails to start within 10 seconds, wait at least 30 seconds before you try again so the starter has time to cool. 

11. Once the vehicle is running, leave the cables hooked up to both running vehicles for at least 5 minutes to allow the weak battery time to recharge and lessen the risk of overvoltage. 

12. Follow the exact same procedure above to remove the cables, but in reverse.

Important safety measures

  • Be sure the two batteries are of the same voltage.

  • Never boost a frozen battery as this may cause an explosion.  Wavy battery walls are generally a sign that the battery is frozen.

  • Never smoke while attempting to jump start a car battery and avoid sparks and open flames.  Remember, batteries give off hydrogen, which is an extremely explosive gas.

  • A car battery contains liquid electrolyte, which is a corrosive sulphuric acid solution that can cause serious burns.  In case of contact with electrolyte, immediately rinse the affected area with a lot of water.

  • Wear the appropriate safety glasses when working around batteries, and remove any rings, metallic bracelets, or other jewellery.

Given the delicate nature of a battery boosting operation, don’t hesitate to call on roadside assistance specialists if you are not entirely familiar with the procedure.  You may have to wait a few minutes for the tow truck to arrive, but it is better to wait inside and stay warm than get outside in the cold and mess it all up.