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car jump

1032 Views 8 Replies 6 Participants Last post by  hilux5084
i was wondering if jumping a car will shorten the life span of your battery, I should just take my jumper cables out of my truck because in the past 3 months I have jumped 6 cars and a big rig (didnt no I could do that). but i would love to know if its gonna kill my battery
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Now this is just my opinion on this, When I jump start another vehicle I have my truck running with the headlights on so that the altenator is charging at a higher amp rate because of the demand,so with the cables hooked up the altenator is doing most of the work and not your battery.
Mainly what kills a battery besides a long life is letting it die down to where it has to be recharged, each time kills it more and more.

Short answer; no.
ejohns06 said:
Now this is just my opinion on this, When I jump start another vehicle I have my truck running with the headlights on ...
Why? With headlights on part of alternator power is waisted on headlights, putting more drain on the battery.

To save battery, just keep rpm up (2 - 3k) while jumping.
well thanks for all the help I have only let it drain once when i had to charge it because i had to work on it with the lights on so thats what killed it then but i charged it so it should be good for a while
Never had a battery last less than 6 years so it must not be hurting it. Raising the rpm is doing the same thing making the altenator charge at a higher rate.
Ok I am looking at buying a starter alt rebiuld biusness and according to the old owner the alt will only put out as much as 14.8 to the battery, depending on how drained the battery is. Now there are bigger alts that go from 65amp to 100 and higher. the more electrics you have on it the more it will draw from the battery. thus the alt works just as hard. Now old generators if you rased the rpms would put more juce in to the battery. but an alt does not work that way. you can do a test your self with a multi meter and show what is registering when you start it up and it it is 14.5 then watch and raise the rpms and it should not move.

charging systems and jump starting ?

I never recomend jump starting with the engine running as you run the very real risk of damaging any electronic devices fitted to you're vehicle because the alternator as Lance stated is a voltage controled device if the alt is running during a jumpstart the system voltage will be low around 10 to 11 volts while the other vehicle is cranking so the alternator will at almost full output 50 amps or so, the when the other vehicle either starts or stops cranking the alt is now producing around 600watts of power this doesnt just dissapear if the current stops instantly the power is transformed into voltage the resulting spike can be around 40 to 50 volts.

This voltage spiking is the most comon reason for the failure of automotive electronic devices in most cases the damage is not instantanious but can take many months to surface as usualy the internal semiconductor protection devices are weakend causing it to fail at a latter time usualy the story of I was just driving and the ignition module just failed or the like is the result.

I allways recomend jumpstarting without the engine running or connecting the leads and runnung the car for 5 minutes to place some charge in their batt then switch off and start the other car.

I hope this hasnt been too long winded or complicated but its better than just saying I dont jumpstart.

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