Can You Jumpstart a Car with a Bad Alternator?

Note: This post may contain affiliate links. This means we may earn a small commission for qualifying purchases at no cost to you.

Last Updated on January 20, 2021

The alternator is what your car battery depends on to stay charged. With all the electrical components which exist in vehicles these days, you would never be able to supply energy to all of them with just the battery power alone.

Looking for a good online repair manual?
Click Here
for the 5 best options.

The alternator is what keeps the battery charged so that it can deliver the necessary energy to these components. So, what happens when you have a bad alternator? Can you still jumpstart your vehicle?

When you have a faulty alternator, there is no doubt that you will need to have it replaced as soon as possible. In the meantime, a non-working alternator has probably left you stranded somewhere because your car no longer starts.

Related: 5 Causes of an Alternator Not Charging

However, for some vehicles, it’s possible to jumpstart it with a bad alternator so that you can get it back on the road and drive it to a nearby auto repair shop.

The vehicle only needs enough electricity to power critical components like its onboard computer (engine control unit), fuel pump, and fuel injectors among other things. If you can generate this much electricity, then it will be enough power to drive the vehicle to a mechanic to get the alternator replaced.

Warning
While jumpstarting a vehicle with a bad alternator may technically be possible, do not leave jumper cables connected between vehicles longer than necessary as it can result in damage to sensitive electronics. See here for more info.

See Also: Causes of a Car That Shuts Off While Driving

How to Successfully Jumpstart a Car With a Faulty Alternator

jumpstart dead car battery

Below are the five steps for jumpstarting your vehicle if you have a bad alternator. Just remember to be very conservative with your power as you attempt to drive your vehicle to the nearest repair shop.

Without a functioning alternator, your battery will only have a small amount of power before it’s completely drained. Instead of being stuck in a driveway or parking lot, you can instead be stuck on the side of the road.

Related: Bad Alternator vs Bad Battery (Which Is It?)

#1 – Get a Jumpstart from a Good Battery

The first tip should be an obvious one. When you need to get a jumpstart with a bad alternator, you’ll want the other vehicle’s battery to be in good condition and have a full charge.

The reason is that your battery is going to be drawing a lot more energy from this other battery than it normally would as you go to jumpstart your vehicle.

Optional: If you have a portable jumper pack (such as the NOCO GB20 or Tacklife T8) in your trunk or glove box, this could be another way to jumpstart your vehicle or at least give you a second jumpstart if you don’t make it the first time around.

These portable jump starter boxes are good, cheap insurance to have, especially since you don't need to find another person willing to help you out.

#2 – Connect Jumper Cables

  • Attach one red clamp to the positive (+) terminal on the dead battery.
  • Attach the other red clamp to the positive (+) terminal on the good battery.
  • Attach one black clamp to the negative (-) terminal on the good battery.
  • Attach the other black clamp to an unpainted metal part (nut, stud, bolt head, or bracket) in the engine bay of the car with the dead battery. This will provide a proper ground.

#3 – Let the Other Car Run for 4 Minutes

Once the jumper cables are properly connected, have the owner of the donor car (good battery) start their vehicle. The car with the dead battery should be turned off during this time.

After waiting about 3-4 minutes, attempt to start your vehicle which has the dead battery and bad alternator in it. If the car cranks a bit but won’t start, wait another 3 minutes and try again.

#4 – Keep the Accessories Turned Off

Make sure all the car’s electronic accessories are turned off. This means turning off the heating, air conditioning, radio, CD player, GPS, phone charger, or whatever else you normally use in your vehicle to draw power from the battery.

You’ll want to conserve as much battery power as you can so that it can successfully power the necessary components.

It’s worth mentioning that you’ll only want to attempt this during a the daylight when it’s dry out. If you need to use your headlights or windshield wipers, then it will use up too much battery power.

#5 – Drive Straight to the Mechanic

If you were successful at jumpstarting your vehicle from the other car’s good battery, then drive straight to the nearest mechanic. You may have a good 5 minutes or so before the vehicle’s power shuts off again.

Do not go on any major highways or traffic-congested streets. Only drive on the slow-moving streets of your current location.

 

10 thoughts on “Can You Jumpstart a Car with a Bad Alternator?”

  1. My car will not start. I got jumping cables and another car to recharge battery. When connected 3 cables and tried to finish with the last one ( either one, + or -) ., I checked all possibilities My car starts like an alarm signal. I could not charge battery. What ‘s wrong?

    Reply
  2. I have a 2008 Dodge Nitro, my husband left the key in the on position. Now Nitro won’t start at all. So I went through 3 alternators. Still will not start. PLEASE HELP CAUSE WE ARE GOING THROUGH A DIVORCE AND I KEEP THE KIDS I NEED MY VEHICLE. PLEASE ANYONE IM BEGGING !!!!!!!

    Reply
  3. Yesterday my car didnt want to start. Has a month old battery and dash lights/headlights/radio all turned on. Once i tried to crank the engine, nothing happened, not even a click. I was told its the starter so I immediately went to buy one, got a mechanic to come out today, and when i tried to use the key fob to unlock the car it didnt work. My brand new battery has drained over night. Is it possible that my starter and alternator failed at the exact same time? Or is there somehow a connection between the starter and the battery failing

    Reply
  4. Hello my car won’t start wen I connect the cords to the battery, It does start tho when I give it a jump but I would have to wait a lil for it to even get enough power. You kan tell it’s receiving power bkz the lights get brighter wen more power is being forced ina car. I had gotten the battery charged an I was still having the same problem, idk if it’s my alternator or do I need a whole new battery

    Reply

Leave a Comment