Is Jumpstarting a Car Bad For Your Battery?

Will I Damage My Car If I Give Someone a Jump Start?

The short answer here is maybe. Let’s explain why.

12-volt batteries simply lack the power to cause significant damage to electronic components – not to mention one can usually find integrated anti-surge protection when charging. As a result, expensive car battery damage happens when you do not connect the ends of a jumper cable properly to both your car and the recipient’s car. Unless you are touching one of the leads to something else and as a result shorting one or more components of the vehicle’s delicate systems, there should not be electronic damage.

How you proceed to crank the car with the dead battery makes a difference. The safest way is to charge the dead battery using the good battery and, after the dead battery is sufficient to start, disconnect the cables and then crank the car with the bad battery.

The less safe way is to crank the car with the bad battery while the car with the good battery is running and both batteries continue to be wired to each other. This method creates a heavier load on the battery, requiring higher currents. Just the act of removing this load from the good battery can create a load dump – a moment where current falls drastically and voltage spikes momentarily due to the inductance of the field winding inside the alternator. This may or may not cause electrical problems.

The safer method is preferred, but make such a decisive action at your own risk.

My Jumper Cables Are Sparking. Is This Bad?

Sparking is dangerous as there is always a small probability the battery may explode, ejecting battery acid in your face. Avoiding this problem is exactly why it is recommended to connect the negative jumper cable to the vehicle body and not the negative post of the battery. Always place the jumper cables in the correct order and way.

Can a Car Be Too Dead to Jump Start?

In normal cases charging a too dead battery for a few minutes before attempting to start the bad battery’s vessel will work. But, in the case that said process does not work, the terminals of the battery may be corroded or the battery itself may be very old and beyond repair. In either case there is also the possibility the problem is found elsewhere – the alternator, a blown starter, etc.

Jump Starting Safety Tips

  • When jump starting, make sure you are not smoking.
  • Make sure the vehicle is in park.
  • Do not let the cables dangle from the car.
  • Do not use poor- and low-quality cables. Use high-quality ones.
  • Refer to your car manual for instructions.
  • Keep a wire brush handy for proper cable-to-terminal connection in the case cleaning battery terminals is appropriate.

The Electronics Guy’s Recommendation

If you want to be the best at jump starting, you need to own the best.

For years I have paid for countless sets of jumper cables that were below $100. Nearly all have failed me up to this day. The following are the most common problems you’ll face with a cheap set:

  • Corrosion
  • Low amperes [current] conduction
  • Bad contact
  • Self destruction of product
  • Having to crank/try more than once. This only happens with cheap sets.
  • Damage to battery.
  • Costlier
  • Damage to either yours or someone else’s vehicle’s electrical/electronics system

I personally learned my lesson years ago. I bought the following product — a product I recommend to all my friends and family. It has paid for itself and I’ve never had the same problem again.

It really does pay for itself. You won’t regret it.

The Only Jumper Cables I Recommend

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