How to Jump Start Your Car – Guide for Using Jumper Cables to Charge a Dead Car Battery

Safely Jump Start a Dead Battery

Many of us have been there. It’s freezing outside and your battery won’t start. Regardless if you’re the person stuck or the Good Samaritan helping out, you’ll want to ensure that the jumpstart is being performed correctly.

There’s a lot of modern engineering that goes into a vehicle’s electrical system. Alternators, batteries and lots of other pieces in between make sure your car starts the first try and keeps running.  When everything’s working correctly these parts are hardly noticeable, but when something goes wrong their importance becomes much clearer.

Generally speaking, jumpstarting with cables or a battery charger is a safe and easy way to quickly power up a dead battery. There are tons of stories of exploding batteries and damage happening to vehicles after an improper jump start, these are mostly false. That being said, there will always be a certain level of risk for vehicles, especially when cables are not used properly.

For the most part, it doesn’t take a lot of mechanical know-how to jump start a battery. The first step is to check the owner’s manual of both vehicles, you’ll want to make sure that neither vehicle has designation connection points other than the battery.

Some vehicles have their batteries stored in strange places. For example, certain vehicles have batteries installed in the wheel well or the trunk. It’s uncommon, but it does happen. These vehicles would typically require the use of a junction block.

Drivers of hybrid vehicles should generally avoid jump starting another vehicle. Many hybrids have a 12-volt auxiliary battery, using it to jump start a vehicle may drain it to the point where the vehicle cannot start.

Cables should be first connected to the donor vehicle’s battery and then to the dead battery. Positive should always be connected positive and negative should be connected to negative. Hooking the cables up the wrong way can produce some scary looking sparks and both batteries could be damaged.

Battery Jumpstart Diagram

Make sure to connect jumper cables in the proper order.

Most of the time the following should be done to ensure a safe charge:

  1. Ensure that both vehicle’s keys are in an off position
  2. Ensure that both vehicles are in Park or Neutral
  3. Connect one jumper cable to the positive (+) terminal of the donor battery
  4. Connect the same terminal to the positive (+) terminal of the dead battery
  5. Connect the other cable to the negative (-) terminal of the donor battery
  6. Connect the other end of the cable to the bare metal on the engine or the frame of the vehicle with the dead battery
  7. Let the dead battery charge for a few minutes. If the dead vehicle won’t start after five minutes, your battery probably needs to be replaced.

It’s very important to drive around for at least 15 minutes to fully charge your battery again.

The process for using a battery charger to boost a dead battery is essentially the same, you’re just swapping a functioning battery for a charger.

Connecting negative to negative may seem like the easier option, but it can cause batteries to explode in rare cases. Why take the chance? Grounding the metal is just as easy and it’s safer for both vehicles.

Generally speaking, most car batteries are basically the same and jumpstarting them is fairly straightforward. Again, it’s important to review your owner’s manual and ensure your jump start is both safe and effective. It’s important to check your jumper cables every season and store them in your trunk.

At CarOne we service and repair all makes and models. We’re a Kingston, ON automotive repair centre that strongly believes in providing high-quality car repairs for an affordable price. We’re more than happy to help with all of your battery and vehicle power system needs.