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Can A Car Jump Start A Semi Truck? (11 Time Saving Facts)

You may be faced with a situation whereby your semi truck battery dies, and you’re looking for a boost.

If there are no other trucks around at the time to help you with a jumpstart, you may be wondering whether a car could do the job.

This may cut your waiting time drastically if you could get a jumpstart from a car.

We will answer this in detail and include the type of car battery you need to jumpstart a truck, the procedure for jumpstarting, what cables to use, and much more.

Here’s a quick answer to Whether a Car can Jump Start a Semi Truck:

A car can use a typical jumpstart procedure to start a semi truck with a 12v battery system. In order to jumpstart a semi truck with a 24v system, two 12v car batteries must be connected in series to make a 24v battery system. Both 12v batteries must be completely disconnected from the car.

How many Amps does it take to Jump Start a Semi Truck?

The amps needed to jump-start a semi truck are around 1500 to 2000. You must know what you are doing when using this amount of power.

It is also essential that you use a car battery that is in good condition. Using a worn-out or old battery may not give you the results you are after.

The truck may start, but the car battery, in turn, may die.

How many Volts does it take to Jump Start a Semi?

The recommended voltage to jump-start a semi truck is 24-volts.

Less than this, and you will probably not get the truck to start. It is worth noting that this could take some time.

Be sure to wear protective eyewear and suitable gloves when dealing with currents. If in doubt, seek professional advice.

Can you Jump Start a 12v Semi Truck with a 12v Car?

You can use any 12-volt battery to charge any other 12-volt battery, regardless of what vehicle.

The procedure would be the same as that of a car however, it will probably take a little longer, and you will more than likely need to keep the car at a high idle.

The procedure to jumpstart a 12v battery with a 12v battery would be as follows:

  • Ensure that your truck is turned off.
  • Connect the one end of the red cable and the black cable to the positive and negative terminals respectively of the charged battery.
  • Connect the other end of the red cable to the positive termminal of the dead battery.
  • Connect the other end of the black cable to the the chasis of the semi truck. It must be a section where the metal is clean and free from paint e.g. compressor bracket or engine manifold.
  • Start the engine with the charged batter and let it run for a few minutes to charge up the dead battery. This could take 2 – 5 minutes.
  • Start the semi truck with the dead battery. The truck should start, if it doesnt, check to make sure the connections are good.
  • Once the semi truck has succefully started, disconnect the cables in the reverse order.
  • Swithch off the car with the charged battery.
  • Allow the semi truck to run for about 20 minutes so the battery is fully charged before driving off.

The same would apply to jumpstart a 24v battery with a 24v battery, or the same voltage systems.

Can you Jump Start a 24v Semi Truck with a 12v Car?

A 12-volt car battery does not have sufficient power to jump-start a 24-volt semi truck battery.

With only half the power, it wouldn’t work. You would need to match the volts of the truck’s battery.

You could use a boost converter to increase the power of the 12-volt car battery to double, which would give you the volts needed to jump-start a 24-volt truck, but again, this requires knowledge, so be careful.

What about using 2 Cars to Jump Start a Semi Truck?

Technically this can be done. Two car batteries would provide enough power to jump-start a semi truck.

However, you would need to disconnect the batteries completely from both the cars and connect them in series to make a 24v battery supply.

If the 24v battery system is connected to either of the cars, it can damage the car’s electronic systems as it is designed to operate on a 12v system.

Once you set up the car batteries to make a 24v battery system, you can connect the positive terminal to the positive terminal of the 24v dead battery, then connect the negative terminals in the same fashion.

Try starting the truck to see if this works.

Read the section “Procedure to Jump Start a Semi Truck Battery with Car Battery below” to know how to do this precisely.

Does the Type of Car Battery VS Semi Truck Battery Matter?

The only thing that matters on a car and semi truck battery is that they are the same voltage.

Brands or type doesn’t matter. A car battery can jump-start all types of semi truck batteries.

It will not hold their charge. It can only help start the truck. It is, however, advisable to do all the required safety checks before attempting to jump-start any vehicle.

How Long to Charge a Semi Truck Battery with a Car Battery?

The length of time it takes to charge a semi truck battery with a car battery will depend on how little power is in the semi truck battery or if the truck hasn’t been running for a few months.

It will need around an hour or more to see any results. If the semi truck has been down and out for a day or more, then you could probably charge it with a car battery in 10 minutes.

When charging it for an hour, you do not need to rev the car engine until you attempt to start the truck.

When charging it for 10 minutes, it is a good idea to rev the car engine as much as you feel comfortable.

What Jumper Cables would you Need to Jump Start a Semi?

The jumper cables required to jump-start a semi truck are 15 to 20 feet long with a 2-gauge thickness. Most manufacturers recommend this for safety and positive results.

The 2-gauge thickness is required to carry the number of amps to the battery without overheating.

The length of the cable is necessary for the size of the vehicle and to reach the battery terminals conveniently.

It is also recommended that you use the appropriate safety equipment such as goggles and safety rubber gloves, with rubber-soled boots.

Procedure to Jump Start a Semi Truck Battery with Car Battery:

A standard car battery is 12-volts. Which would mean you probably need two cars or at least two car batteries.

Some pickup trucks have two 12v batteries connected in parallel, you could use this as well.

It’s recommended to use rubber gloves, safety goggles, and boots when performing a jump start.

Here are the steps to jumpstart a 24v battery with two 12v batteries:

  • Check the vehicles have their parking brakes on. Park the car on the same side of the truck the batteries are.
  • Open the car’s bonnets or boots, depending on where the car battery is located. Open the side battery cover on the semi truck. Remove rubber terminal covers on the truck’s battery if it has one.
  • Disconnect all terminals of both car batteries.
  • You will need the truck’s long jumper cables as well as the car’s jumper cables.
  • Use the car’s black cable to connect from the positive terminal of one 12v battery to the negative terminal of the other 12v battery.
  • If the cables are thinner than a 2-guage thickness cable, you should use both the red and black cables for this connection, to avoid overheating and burning the equipment.
  • Then use the 2-guage jumper cable (black) to connect the free negative terminal of the 12v battery to the negative terminal of the truck battery.
  • Use the other red cable to connect the free positive terminal of the 12v battery to the positive terminal of the truck battery.
  • Now start the truck. If both 12v batteries are good, the truck should start.
  • Once you have successfully started the semi truck, remove the jumper cables and put them safely away, cover battery terminals and allow the truck to run for about 30 minutes to fully charge its battery before driving away.
  • Reinstate the 12v batteries to the cars.

Here is a schematic of how the batteries are to be connected:

The car battery will be ok when driven for a few miles. Have the battery checked at your earliest convenience.

Can you Damage your Car Battery doing this?

You could only damage either battery if you fail to connect the cables properly. You could cause the battery/s to explode and cause expensive electrical damage to the vehicle/s.

It is our recommendation you follow correct connection procedures to avoid this expensive mistake. If you are unsure, get help from a friend or a professional.

Repairing damage to a vehicle’s electrical system could go into the thousands. A simple check to make sure your batteries are connected properly will save you a lot of downtime.

How can you Prevent your Semi Truck Battery from Dying?

Preventing your battery from dying is easy. Remember to turn lights, a radio/stereo off.

Although trucks have alarms as a reminder, they can still be missed. A long day at work, and a truck driver sometimes doesn’t hear that alarm.

Inspect the battery terminals and cable connections every two to three weeks for corrosion and any loose connections.

Avoid unnecessary idling. Leaving the truck running when stationary can drain the battery slightly as it takes a lot of power to keep going.

The changing of weather from moderate to extreme or back again, along with the vibration, can cause cracks in the links. Check cables after any extreme change in temperatures.

Keep the battery clean from dirt and grease. Check case mounting isn’t corroded or damaged and is dry. A wet mount will eventually rush and could spread to the battery.

Stick to manufacturers recommended batteries to prolong the life. Avoid aggressive acceleration or braking. A change in power can reduce or increase battery power too quickly.

Ensure the battery is in tightly. Test the battery’s power at least once a month to ensure it is working at maximum voltage. Avoid using electronics while idling.

Short runs can seriously reduce the battery’s life.

Where possible, park the truck in an enclosed area to keep the battery warm. The wind draws the much-needed heat away from the battery.

Keeping the battery fully charge by being constantly on the go will help prolong its life.

Happy Trucking!

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