Jump Starting A Modern Car

Jumpstart a Modern car. Is it safe and how to do it?

Assume a situation where your car just wouldn’t start and you identify the cause to be your dead battery. You are tempted to bring out the jump leads from your boot and jumpstart your modern car.

But there is something that you need to know before you even try doing it. A car made after the year 2000 is likely to have a dozen mini-computers and even more small digital devices. Jumpstarting the car without proper knowledge of how to do it safely may fry your car’s expensive components.

Read More: Jump Starting Your Car: 8 Things You Should Never Ever Do

These mini-computers often talk through a shared data bus. Damaging one electronic component may result in a dead data bus with all other devices also being shut down. This can be an extremely expensive encounter.

Dealing with a dead battery in a modern car requires new equipment and new techniques. Read along to have a better understanding of what equipment you need and how to do it properly without the risk of damage to the car or yourself.

Read More: Battery Jumpstart and Other Car Battery Tips You Shouldn’t Miss

Prevent Voltage Spikes

When you try to jumpstart a dead battery from a running car, the running car will instantly flush the maximum charge through the jumper cables. This will create a voltage surge of up to 15.5 volts in both cars. It may start the dead car, but it has a huge risk of frying the electronics inside both cars.

One way to avoid damage to the donor car is by keeping its engine off while giving power to the dead car. The dead car electronics are still prone to electrical surges.

What are jumper packs?

Jumper packs in simple words are portable-external sources of power that carry enough power to jump-start a dead car battery. They operate at a safe voltage or have a voltage controller for precise needs. A jumper pack uses a battery with sufficient power as its power source.

When used correctly, a jumper pack will provide enough power to the engine to start it, while functioning at a safer voltage to ensure the safety of electronics.

How to use a jumper pack

Using the instruction manual to know your jumper pack is the most ideal situation. But in case you do not have it handy, here are some general rules that you must follow on how to use a jumper pack or jumper box.

  1. Turn off all the lights and electronics inside the dead car including the radio, lights, air conditioning, indoor lights etc.
  2. Now connect the cables of the jumper pack similarly to regular jumper cables. Attach the positive alligator clamp (red clamp) to the positive post of the battery.
  3. Connect the negative alligator clamp (black clamp) to any metal part of the engine or the car’s body for proper grounding. It should not be attached to the negative terminal of the battery.
  4. Turn on the jumper pack.
  5. Now crank your engine. Make sure you check the jumper pack’s manual for the number of times you can crank if it didn’t work the first time.
  6. If the jump worked, let the car run for about 5-10 minutes so that the battery charges itself sufficiently.
  7. If the jump didn’t work, you tried your best without damaging any components.
  8. Turn on all the electronics in the car including the radio, heater, wipers etc to avoid an electrical spike when the clamps are removed.
  9. Removing the clamps is a reverse process. You have to remove the negative clamps (black) first. Then remove the positive clamps (Red). Maintain safety at all times and avoid getting in contact with any moving parts inside the engine.
  10. All electronics should be working fine. But it is still advisable to look at your dash to see any warning lights. It will be a quick check that all equipment is working fine.

Jumper Packs vs Power Packs

Powerpacks are recreational power banks that offer stable electrical power for longer periods. Jumper packs on the other hand provide a high burst of power for a short period.

Powerpacks are created to get you through power failures or act as a portable source of power at camping sites, picnics etc. They can sometimes be used to jump a slightly discharged battery. But they are not a reliable jump solution. Jumper packs are specifically designed to deliver maximum power within a short duration of time.

Therefore, you are looking for jumper packs to jump-start your car and not power packs.

How to choose the right Jumper Pack

Jumper packs are advertised with peak amp ratings and crank amp ratings (CA). Ignore the peak amps rating as peak amps are not a reliable indicator for our specific use of jumping a dead battery.

Instead, look for Crank amp ratings to buy the right jumper pack. You need a minimum of 225CAs to jumpstart a 4-6 cylinder vehicle. If you have a bigger engine, opt for a jumper pack with 400CAs or above.

Read More: The Procedure to Safely Jump Start A Car With A Dead Battery


Your vehicle battery can be discharged because of many reasons. Leaving the electronics on, not using the vehicle for a long time, snowfall, flooding, etc are some of the most common reasons. A jumper pack is a handy tool that sits in your trunk and offers reliable power when you most need it.

You could also use jumper cables and another car to jump-start your dead car while putting your car’s electronics at risk. A jumper pack costs anywhere between $120 and $200. Electronic damage will cost you a minimum of $500. The choice is yours.

If you are still unsure whether it’s safe or not to jump-start your car or you do not know how to do it properly with proper safety measures, it is best to call for professional help or roadside assistance. Swift Battery Specialist is your partners in times of such breakdowns and will assist you roadside for a quick solution. They are also your go-to battery specialists with premium batteries available at affordable prices.