Does it really kill your car battery to jump someone else's car?

1. 82

   ezhangposted 13 years ago

   Does it really kill your car battery to jump someone else's car?
   
   I heard that you may be doing harm to your own car's battery by helping someone jump start their car. Is this true? Why would that be the case?
   
   

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   1. 51

      taimur kianiposted 4 years agoin reply to this

      as per my opnion yes it does because this helps reducing the strenght and maximum charge of the battery.

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      1. 57

         mashinbankposted 4 years agoin reply to this

         it's true.
         it helps reducing the strength of the battery

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            victorypi1posted 4 years agoin reply to this

            The possibility of a short circuit somewhere in the battery cable of the vehicle being charged.It, would short circuit your battery and alternator as well.The odds are against such an occurance ,but it is possible.
            If,the battery your trying to charge is old and needs to be replaced will not take a charge.

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2. 74

   someonewhoknowsposted 13 years ago

   The possibility of a short circuit somewhere in the battery cable of the vehicle being charged.It, would short circuit your battery and alternator as well.The odds are against such an occurance ,but it is possible.
   If,the battery your trying to charge is old and needs to be replaced will not take a charge.

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3. 61

   twilanelsonposted 13 years ago

   I do believe you can damage your car battery by giving a jump start.  A friend was giving a jump start to his girlfriend and his battery caught fire.  He is not driving that Mercedes any longer.

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4. 0

   nikashi_designsposted 13 years ago

   Yes, repeated jump starts will cause damage to your electrical system. "Reverse Flow"  When the car that requires the jump is cranked, for a brief second more current is redirected to the donor vehicle.  Thanks

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      Craigrendelposted 9 years agoin reply to this

      Thank you.  I'm glad somebody finally answered the car battery question correctly.  Some people have no clue about their car battery.  Engineers only make car batteries 12V or less. This keeps misinformed mechanics from dying from electric shock. LOL

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5. 77

   LuisEGonzalezposted 13 years ago

   The answer is yes. If the battery that you are charging has some electrical issues (usually a short) it can damage yours.
   
   However, a simple solution is to connect  the jumper cable negative portion that goes to your battery to a metal section of your car, thus not allowing a feedback from the other  "possibly" damaged battery.
   
   In other words: positive to positive, your negative to metal the other negative to negative.

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      Joel Mauldinposted 10 years agoin reply to this

      Some of this is not true. The ground of your car is directly connected to the ground of your battery. There is virtually no difference between connecting to the ground of your car or the battery terminal. Run the car engine to avoid "feedback".

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         victorypi1posted 4 years agoin reply to this

         Yes. It is never recommended to jump start anything with your vehicle, especially a bigger vehicle.

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      Craigrendelposted 9 years agoin reply to this

      Joel's comments are preposterous.  HE IS WRONG. I don't have enough room for a discussion about electric circuits and motors but as an metallurgical engineer I can guarantee you that jumping your battery wrong WILL affect its subsequent performance.

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6. 61

   jchaneyposted 13 years ago

   Yes. It is never recommended to jump start anything with your vehicle, especially a bigger vehicle. Besides the possibility of killing a battery cell you can cause some major electrical issues with your battery, cable, alternator and possibly your computer.

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7. 71

   platinumOwl4posted 13 years ago

   Not if  you know what you are doing. The correct way to make the connection are as follows: connect the cables on the first car black to neg and red to positive on the second car red to positive and the black to a good ground some metal on the engine or frame. This will eliminate the problem.
   
   The first car is the one with the good battery.

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8. 55

   ibbarkingmadposted 13 years ago

   Lead acid batteries degrade if run below 50% charge. The reason why they are ideal for cars is because overcharging them is not an issue. Connecting jumper cables incorrectly is bad and jumping with battery that has not been topped off with distilled water or has issues is also bad.
   However, often when you jump another car your engine is running. In this case, the thing that is "jumping" or charging your friend's battery is being charged by the alternator which is what charges your car battery.
   So to summarize, no, jumping a friend's car is not bad for your battery, BUT there are things you should do to prevent user error and things you should do to maintain your battery to keep it living longer.

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9. 83

   Barbsbitsnpiecesposted 13 years ago

   @ezhang...Absolutely not if the battery that needs charging has no other faults. Once the low car battery is started with a jump, it is best to let the batteries remain connected for a few minutes, so both batteries will recharge. You must have the cables correctly connnected, negative to negative (ground) and positive to positive.
   
   I drove a newspaper motor route for years and charged a lot of batteries!

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10. 60

    kipronorposted 13 years ago

    Normally a car battery runs out of charge if you have left electronics without switching them off, Lights and perhaps the car stereo. If you have not checked the car wiring system to ascertain if there is leakage or probably short circuits that in the long run affect the battery stability. Ensure that your battery is well insulated and your system well earthed.
    Jump starting a car does not run down the battery....perhaps you only loose a little charge, but if done for a longer time without being recharge you loose the charge, the trick is to jump start and then reconnect your own battery.
    Your connections must be well connected to avoid short circuits and ensure you have quality jumper cables to avoid arcing or heating of cables.
    All the best

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11. 69

    Etherealenigmaposted 13 years ago

    It's never killed mine. I'd say if your battery was really weak, it might, but generally speaking, no. Now if you are talking about repeatedly doing it...alot...that could lead to problems, but for the once in a while you might do it to help some stranded soul...no. Besides, the car recharges as you drive it, so unless you already have a problem with your battery, I'd say the answer is no.

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12. 0

    Rosemary Banksposted 13 years ago

    Yes it will kill your battery, I don't give nobody a jump not even my children.

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    1. 74

       someonewhoknowsposted 11 years agoin reply to this

       If,your car has a small battery & maybe even a cheap battery and it's one of those economy cars that has little or no  accessories that most other cars have then I could see a problem .Your smaller battery & or alternator would not be up to c

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    2. 38

       Borsiaposted 11 years agoin reply to this

       I was in the auto parts design & manufacturing business for over 30 years and I've yet to see a car that would be hurt so long as it is done correctly.
       It could drain your battery, which will recharge, so hook it up and run the engine for a minut

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       Craigrendelposted 9 years agoin reply to this

       You don't have to fear giving people a jump. Be sure it is from a big battery to an equal or smaller battery voltage -wise.  Remember to put the negative of your battery to the frame of the car instead of the terminal. This way you cannot be damaged.

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13. 60

    knowledgeispowerrposted 13 years ago

    As my elder's are connected with the business of batteries. So, according to my information and knowledge it is not like this. If you want to start another car by plugging wire to your battery, so there are some ways also for the protection.
    1. First start your vehicle.
    2. Then plug the wires to your battery, Positive with + and negative with -.
    3. Then when you are going to start another car, first race your own car, i mean to say that press the accelerator, then start the another car.
    If you will follow these ways and your battery blast then tell me i will send you the money for the new one.
    If it is very difficult for you then remove the wires of your car from your own battery and then connect the other car battery and then start easily.
    But both the ways, you will find beneficial, because after my great experience i want to share my views about the concern question.

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14. 76

    CloudExplorerposted 13 years ago

    Well electronically if you have your car running, your alternator will keep your battery charged.  Maybe if you shut off the car and leave it connected, then I can see it draining your car battery.  If you make the wrong battery connections from the contacts it's possible to kill the battery as well I believe because of making the wrong polarity connections, positive to positive lead so on and so fourth is the correct contact connections. 
    
    I've seen a battery almost explode once before while people were trying to jump a vehicle, so make sure you place the Jumper contacts to the right battery posts.
    
    Note:  Red is the hot or the positive lead (+), Black is ground or the negative (-) lead.  Make sure your jumper cables aren't worn or broken, this will ensure that the electrical connection is a solid one.  Also make sure that your car, the one that's being used as the source of power to restore the dead battery, is running before making contact connections.

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    1. 66

       Doug Cutlerposted 8 years agoin reply to this

       I blew the top off one when testing a starter from another car.
       My car was running and charger my battery when I put the starter next to it and jumped the starter. It sparked and exploded the hydrogen that was accumulated in the battery..
       Now I wait!

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    2. 0

       johnmariowposted 7 years agoin reply to this

       If, when trying to jump start another car, one accidentally reverses the polarity of the connections from one battery to the other; one can  ruin the alternator and/or the voltage regulator. This happened to me once.

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15. 0

    vperryposted 13 years ago

    It shouldn't.  If your car is running, it should not drain the battery at all.  I've done this many times for friends over the years and have never had a problem with it.  If it does drain it a bit, once you run your car, it should recharge your battery.

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16. 51

    Didyoueverwonderposted 13 years ago

    If their car has an eletrical problem then yes

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17. 61

    wesley5159214posted 12 years ago

    absolutely not.  When you jump start somebodies vehicle you are simply transferring electricity from your alternator to there battery.

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       Craigrendelposted 9 years agoin reply to this

       You couldn't be more wrong.  Too bad.

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18. 83

    richardbrown81posted 11 years ago

    LOL... yes, especially if you put the cables on wrong...then leave them there.  Positive to Positive and Negative to Negative(all cars are grounded to the negative pole on the battery).  If you get them mixed up, then you will see a huge spark when you put the second one on.  The voltage has just sky rocketed!  Otherwise no, your accually charging thier battery with your alternator.  Jumpstarting their car is the equivealent of starting yours, a couple times in a row.

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19. 38

    Borsiaposted 11 years ago

    Done correctly it will have no effect on your battery or your car.
    1. Connect the + side of your battery to the + side of the car to be jumped using the red cable. Check the marking on the battery not just the red / black color coding but red should be +.
    Next connect the Negative cable to your battery - terminal. Then connect the other end to a metal place on the other car's frame or engine. This is to prevent a dangerous spark near the battery.
    Start you car and run it at a medium high idle. If your car has a tachometer it should be about 2500 rpm.
    Wait a few minutes before trying to start the other car.
    The only thing that can cause issues is getting the connections +- crossed so be careful to get them right.
    This will have absolutely no ill affect on your car or battery.

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    1. 66

       Doug Cutlerposted 7 years agoin reply to this

       I agree mostly.Two exception is if you had an old 6 volt system. Or like another said a badly shorted battery.
       
       Or a rare one is if one car has  positive ground and the bumpers were touching. B4 the 60's some had this.

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20. 87

    tsmogposted 11 years ago

    Usually  not. However the load may blow a diode in the donating vehicle's alternator.

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21. 85

    annajazzposted 11 years ago

    In the general sense, no it can not hurt your battery. The sole purpose of a car battery is to charge things, and thus...But really its your alternator that is doing all of the work
    
    Now, here are a few way that it can:
    1. If there is something wrong with the jumper cables.
    -They can be damaged/frayed and could cause a short.
    2. The batteries of the cars are not the same voltage/size
    -This can cause melting of the connector wires, thus leading to a battery catching on fire.
    -This can also drain your battery, if, say that you have some mid size car and are
    trying to jump a pickup truck like a diesel a Chevy Sierra.
    3. How you connect the jumper cables
    -If you do it wrong, you can hurt the battery and yourself

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22. 52

    thom langposted 10 years ago

    I see many answers here that are correct.  In the earlier days some cars were okay to give someone a jump.  It still is in some cases.  The story that it was bad was from some cars that  had a different diode in the alternator than others, preventing a sudden surge or draw of current.  It does cause a problem depending on what caused the battery in the that needs the jump to die.  If you disconnect your battery before jumping them it can not throw a sudden surge to your car.  I have a jump pack so I do not need to worry.  In most cases it will not hurt, but there are many things you need to know first.  I spent many years in the battery business, one more start will not hurt the battery, it is the other things. If you think of the battery as a bucket of water, when you take some out to start the alternator puts it back.  If you see a battery that is swelling, it is getting overcharged.  If the car that needs jumped has a swollen battery it is being overcharged, except it does not overflow.  It may explode with a jump.  As many things dealing with electricity, there are many variables

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23. 80

    tehgybposted 10 years ago

    No, however it could damage your car's electrical system if you don't connect the jumper cables correctly. Be SURE you're jumping the car per the manufacturer's recommendations.

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24. 61

    herbalistsposted 10 years ago

    yes  because its old and it will just make our burn therefore do not use that battery. the car is expensive than the battery

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25. 84

    nanderson500posted 10 years ago

    Most of the time, no. I have helped a couple of people jump start their car without any problems, and I'm sure that most people could say the same. It's possible that it could damage your battery though, under certain circumstances. .

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26. 70

    Kate Mc Brideposted 10 years ago

    No-once you drive your car again the battery recharges itself

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27. 72

    thranaxposted 10 years ago

    Personally I never had an issue. I have a 2001 Ford Suv with an all weather big battery in it that I dont even know the age of (bought it used) and I have jumped between 80-100 cars with that battery and it works fine. Maybe because all of the vehicles had the same size or smaller battery. My suv has never seen a loss in performance and starts up right away.
    
    ~thranax~

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28. 0

    MrDanielAbramposted 9 years ago

    No it does not kill your car battery to jump someone else's car. I have done it many times before.

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29. 50

    MindMatters2posted 9 years ago

    NO! You can not kill your cars battery by jump-starting someone else's car, unless your car is not running, and the other car has different issues, (instead of just a low charged battery). (ALWAYS MAKE SURE TO ATTACH (RED) TO (+) AND (BLACK) TO (-) AND MAKE SURE THE TERMINAL POST CONNECTORS ARE TIGHT ON BOTH CAR BATTERIES, because maybe it's not a dead bad, just a bad connection.) But as long as you run your cars engine at the time of the helpful Jumpstart, Your Alternator will keep your battery electrically healthy, (providing that there's nothing wrong with your cars alternator!) I also have to mention, some replacement terminal post connectors are painted (red) and (black) for easy visual connection, just make sure if this is the case, to scare the painted surface away where the cable's are going to make contact, to ensure 100% connection.

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       BilalCBposted 7 years agoin reply to this

       hmmm http://dostifm.com/

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30. 68

    Huntgoddessposted 9 years ago

    I have always wondered about this myself.
    
    I see there is much good information coming from Hubbers here, so I'm going to try to learn by reading those.

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       Huntgoddessposted 8 years agoin reply to this

       I've been taking the bus for several years now. So I don't anticipate having to think  much about this in the near future. Possibly never again?
       
       I was never a real strong driver. I didn't learn to drive until I was 49.  Not sure I even miss it?lol

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31. 84

    Au faitposted 9 years ago

    Never killed mine.  Have given assistance several times.  No problems as a result.

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32. 60

    BigBlue54posted 9 years ago

    I have never found it to do so but one piece of advice I would give is have your own engine running when you do the jump start. Just let it tick over if you want or just give it a little bit of throttle. I have usually found that because your engine is putting some charge back into the battery it helps the jump start.
    
    Though it has never happened to me I know of someone who helped start another persons car without having their own engine running. The other car took some starting. Eventually it did but the helper discovered his battery was flat. the person he had help had left. Yes you've guessed it. He then needed a jump start from a third person.

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33. 0

    Joshtheplumberposted 9 years ago

    Not necessarily. It can interfere with electronic components of your car, but if you turn everything off and the engine is running, your alternator is doing most of the work. What causes batteries to explode is the hydrogen gas that is produced by the chemical reactions going on inside. The dead battery will have more gas around it than the good one. This is why the last connection, which produces the spark, is best made to the frame of the vehicle that is being used to jump.

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       Doug Cutlerposted 8 years agoin reply to this

       I believe you got that backwards. The charging battery is the one that is putting out the hydrogen. I blew the top off one testing a starter on top of the battery while the engine was running. Also you will see the hydrogen bubbles while charging

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    everythingbikeposted 9 years ago

    Not at all. You can take your battery out of your vehicle and place it in the other vehicle and start it. When the engine is running, just remove the battery (whilst the engine is running) and place it back in your vehicle. If you do chose to run your vehicle whilst trying to jump another vehicle, keep your lights on which helps power spikes when the other vehicle starts which can damage your electronics.

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       Shyron E Shenkoposted 8 years agoin reply to this

       Peter, if a car is running and you disconnect the battery then the motor will stop running.

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       fer-nieposted 7 years agoin reply to this

       @Shyron, I think the second alternative he is giving is under the assumption that you don't want to disconnect the battery and would rather keep your head lights on.

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35. 83

    Dakkposted 9 years ago

    Depends on how well the battery is, me thinks. I've seen old batteries get incredibly hot and almost explode during a jump start attempt, but that only happened once, and it was an old car with an old battery. Never had a problem with newer batteries, altough some mechanics swear that it can ruin the battery if you do it often. I have no special knowledge about this, so I can't say for sure, but chances are that its not good for your battery if you do it several times.
    
    Once or twice should be ok, though.

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36. 73

    Shyron E Shenkoposted 9 years ago

    Usually it will not but, in the case of not connecting the cables correctly, which will short the battery, or trying to jump someone's car without the one doing the jumping running, that would drain that vehicle's battery then it would need a charge.

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37. 60

    YvetteParkerposted 9 years ago

    I've given a jump before and it didn't kill my battery. I've had others give me a jump without it killing their batteries. I suppose it could be possible to kill your battery depending on its condition at the time. If your battery is already weak, then a jump may cause possible harm.

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       Doug Cutlerposted 8 years agoin reply to this

       There is an issue about the diodes in the alternator going out it you do it wrong. Like, if you put a good battery in, start engine, leave running, remove good battery, put back in discharged battery. The "no battery time" can damage the diodes.

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38. 0

    JG Hemlockposted 8 years ago

    Do you know...I was told that it did but I have given so many jumps from my car and I have never had any problem with my car battery. The usual replacement and one time my battery lasted almost 6 years!

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39. 59

    mechanicsguyposted 8 years ago

    That's the best way if you're in the middle of nowhere

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40. 61

    DonSteveposted 8 years ago

    Nope.
    Keep your car engine running in order for the alternator to charge the battery and give the other person a jump start. That's the safest way to do it.

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41. 58

    Jessica Dixonposted 7 years ago

    I've never had a problem doing this, used to regularly use my car to jump start a classic car which was a work in progress!
    
    More and more modern cars make it impossible to jump start from them. I guess it can damage your car if you have the fancy start/stop technology!

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42. 80

    fer-nieposted 7 years ago

    Anytime you're dealing with electricity, there's a risk. I might not be an automotive expert nor be an engineer (I'm going to school for it), but what I do know is jumping someone else's battery always carries a risk.
    
    You're doing someone a favor by jumping their battery. In the same token, you're also risking your electrical systems and such. And, interestingly, you could end up with a worse-off car. I had a car that wasn't the same anymore, especially after jumping a stranger's car. I was afraid I pushed the PCM or something. Although I doubt that was possible, my cluster was acting funny after that.
    
    Jumping someone's car is no joke. Just keep your car nice and tidy, make sure it is well-grounded, and you should be O.K.

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43. 70

    WrenchWenchposted 7 years ago

    Does it really kill your own battery to jump someone else's car? Are there any ways to protect your battery when helping out a friend? Read this article to find out more. read more

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44. 54

    Kishernposted 7 years ago

    No it magically charges your battery and theirs.

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45. 48

    Rakhigarciaposted 7 years ago

    Jump starting a car does not run down the battery. You only loose a little charge, but if done for a longer time without being recharge you loose the charge, the trick is to jump start and then reconnect your own battery. Your connections must be well connected to avoid short circuits and ensure you have quality jumper cables to avoid arcing or heating of cables.

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46. 60

    venus Psychicposted 7 years ago

    definitely yeas.. better take your time , remove the battery  and recharge it in a gentle method at home .. recharge faster always kill the battery lifetime . x from Venus psychic

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    alanjakewashingtonposted 4 years ago

    Yes, do not jump on even your car also

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    electronicsguyposted 3 years ago

    I wrote a pretty good article on this. When you jump start someone else's battery, a momentary spike in current jolts either system. This momentary spike in current could be avoided with overcurrent protection that could handle such a spike in current. However, not all electrical subsystems can handle this. As a result, damage can occur.

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    MARTINS CHUKWUMAposted 17 months ago

    Jumpstarting another car can be risky if not done properly. The main risk is electrical damage to one or both vehicles. There is also a risk of injury due to electrical shock if the procedure is not followed correctly. Additionally, if the jumper cables are not connected in the right order, it can cause damage to the electrical systems of the vehicles involved.

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