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SHORT ANSWER:
Normally speaking, with a typical jumpstart, it SHOULD NOT damage an alternator.
LONG ANSWER (not a typical jumpstart):
The only ways I even remotely see jumpstarting a vehicle damaging one's alternator are:
1. If the alternator is already severely or, in rare circumstances, slightly damaged.
2. The amperage required by the other vehicle's starter severely exceeds the maximum output amperage of the alternator AND the maximum (cold [?*]) cranking amperage of the battery together.
Usually, in most typical jumpstarting cases, the battery in your vehicle will supply any excess amperage required above the altornator's output.
3. If one's vehicle is MUCH smaller than the vehicle it is jumpstarting and one's vehicle does not have a battery with a maximum (cold [?*]) cranking amperage required to start a MUCH larger vehicle --- typically a larger vehicle means a larger motor and therefore a larger starter which will require a (significantly) higher amperage to turn the motor over with the (minimum) troche and speed required to start the vehicle's motor. (Such as in my story below.)
(possibly)
4. If the battery in one's vehicle is extremely low in power --- such as a vehicle that was recently jumpstarted and did not have enough running/charging time pass to get a good charge on the battery before attempting to jumpstart another vehicle --- and cannot produce the amperage required by the other vehicle's starter, the alternator may/will be forced to supply almost all the amperage required by the other vehicle's starter; which can easily exceed the maximum output of one's alternator depending on the maximum amperage rating of one's alternator (with a possible output range of a factory alternator of being anywhere from 50 to 150 amps for a typical car or small truck and 125 to 350+ amps for a truck) and the amperage required by the other vehicle's starter.
REFERENCE: self-experience with many bad alternators (Seven in two and a half years to be exact!) and jumpstarting in my first car ('95 Honda Civic LX)
MY STORY:
Only once did my alternator die shortly after jumpstarting a vehicle, a big heavy duty, I cannot even remember the manufacturer anymore, v8 truck (I did not even think to turn off the sound system, but I did turn it down, which was still pulling nearly 20 amps by itself, but thats out of the almost 180 amps it pulled turned up as loud as it would go before the sound started to get distorted) his started required (guessing) around 650 amps (cold start on 40 degrees F night) my alternator rated at 85 amps and my battery being 5 years old and only ratted at 350 amps and 425 max cranking amps. Needless to say that this also melted the insulation of the 2 gage jumper cable I used. (I should have known better than to do that, but I wasn't thinking about it at the time.) Shortly after the cables started smoking I gave up and less than 10 miles down the road my batter light came on, by the time I got home the battery itself was down to 7.14 volts from running the headlights and windshield wipers for the next 25 miles (30-35 minutes.)
After all was said and done I've replaced the alternator and decided to go ahead and replace the battery, just incase it was also damaged. Since then I don't think I ever went more than 7 months without the alternator failing, thankfully Autozone has a 1 year warranty on the alternator and battery so I never had to pay for the part again, all the alternators for the Honda were unfortunately "refurbished" which is probably why they kept failing, the third alternator ruined my battery by pulling 11.5 amps to ground when the motor was off (but when the car was running, it could charge the hell out of the battery.) The forth alternator was producing a crazy 37+ volts when the motor was running. Thankfully; after the second alternator, I put a voltmeter in the 12v auxiliary plug (cigarette lighter); because, that high of voltage could have easily ruined a lot of things like the battery, computer, radio, amplifiers, and many many more items if left unnoticed. All the other alternators just died on me without a (noticed) reason.
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∙ 9y ago
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What cause an alternator to blow?
The usual cause of a blown alternator is overload. The alternator will also blow if the battery is connected backwards, even for an instant, such as during jumping. Sometimes, overload is caused by attempting to jump start another car while revving the engine of the first car. The alternator is not designed to carry the current of a starter. Depending on the alternator, protection might be built in, but don't count on it. Rev the engine only to help charge the other battery, and then let the engine idle while starting the other.
Will jump starting another car harm my car?
It can. Some new cars warn against jump starting another car. Others have special locations to put the jumper cables. I have seen people blow out fuses doing it wrong. Call a tow truck for the jump. They are trained, and if they cause a problem, you have some recourse.
Your car wont start just makes a clicking sound?
That could be the alternator or the battery. Try jump starting your car with another car's battery. If it still does not start, it is probably the alternator. If it starts, your battery is dead.
Your 1997 Mazda 626 will not start after an alternator malfunction why?
Battery will be flat because spark plugs were running straight off your battery because the alternator was not charging your battery as you were driving. You can test this by jump starting your car with another car and after your car is running you should be able to disconnect your battery and car should still run off the alternator. If your car stops than your alternator is RS. Battery will be flat because spark plugs were running straight off your battery because the alternator was not charging your battery as you were driving. You can test this by jump starting your car with another car and after your car is running you should be able to disconnect your battery and car should still run off the alternator. If your car stops than your alternator is RS.
Why does my car start after jump starting but then dies?
Probably the alternator is bad. Once the jumper cables are removed, there is no source for ignition if the alternator is bad. Have it tested and replaced if necessary.
Will jumping a car batery damage alternator diodes?
Not if you jump it from the battery or electrical system of another car.
Will jump starting a dead truck battery drain a car battery?
If the donor vehicle is running and has a properly functioning alternator, no.
What if you clean terminals on car battery and give it a jump and still dies out?
battery and or alternator are shot, check alternator by starting the car, and removing either the positive or negative battery cable,,, if the vehicle continues to run the alternator is good.
How long do you have to drive around to charge a car battery after jump starting a car?
You should never drive a car around for long after jump starting a dead battery. This puts an enormous strain on the alternator. Alternators are designed to keep a good battery charged, not to charge a dead battery. You can easily burn out a diode in the alternator. Jump start the engine and drive it somewhere and connect a battery charger to the battery and charge it fully.
Will jump starting your battery on a 2002 Cavalier cause the check engine light to come on?
Check engine lights can come on for a number of reasons. If you didn't get the cable right or got a sparks when connecting or disconnecting that could most definitely cause problems with the check engine light or even blow the alternator fuse.
How long does an alternator last?
That depends on a number of factors. On the average, you ought to be annoyed if your alternator goes bad in less than 5 years or 50K miles. The following will cause an alternator to fail quicker:high under-hood temperatureslots of high-draw electrical accessoriesweak batterybad jump-starting techniquedirt, water, sand, grease and foreign debris caked on, and in, the alternatorSometimes, what passes for a failed alternator is simply a bad diode pack. You might be able to swap a new diode pack in and get another 100K miles on the alternator.
Do batteries stop working because you jump start them?
It is possible, especially if the battery is old. It is more likely however to blow something else electrical in your car. Before jump starting read the manufacturers recommendations on how to do it for your particular vehicle.
