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Schiffer

How To Jump Start A Car

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So most of the people who owns a vehicle, doesn't know how to jump start a car. So i thought about sharing this.

You'll need to park the running car next to the dead car in such a way that the jumper cables can reach both batteries.

If you aren't sure where the batteries are under each hood, take a peek* before you park.

for example, there are some van's where the battery is under the side footsteps of the rear sliding door.

Step 1

Make sure both cars are turned off

Step 2

Connect one end of the red (positive) jumper cable to the positive(+) terminal on the stalled battery.

jumpcar2.jpg

Step 3

Then connect the other red (positive) cable clamp to the positive(+) terminal of the good battery.

jumpstart.jpg

Step 4

Connect one end of the black (negative) jumper cable to the negative terminal of the good battery.

carjump2.jpg

Step 5

Then connect the other black (negative) cable to a clean, unpainted metal surface under the disabled car’s hood. Somewhere on the engine block is a good place. Unless you want to see flying sparks and a possible explosion, do not connect the negative cable to the negative terminal of the dead battery, .

carjump7.jpg

Step 6

Start the car that’s doing the jumping, and allow it to run for about 2 to 3 minutes before starting the dead car.

Step 7

Start the dead car

Step 8

Remove cables in reverse order.

Step 9

Keep the jumped car running for at least 30 minutes to give the battery sufficient time to recharge itself.

Important Tips

Disconnecting the battery - be sure you don't let the red and black cables touch each other at the end when they are still connected to one battery.

If the car wont start properly - check to see if your battery or connections are corroded. If they are, sometimes a little wiggling while the cable clamp is connected will make your connection better. Otherwise you might have to clean the connections with a wire brush.

Don't be nervous about your battery connections, but also know that it's very important that you do not mix up the cables or you can do serious damage. The hardest part of the job is simply remembering where to put each cable.

Hope this will help someone :)

Source: The Art Of Manliness & About.com

Edited by Schiffer
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Thanks schiffer. Can you explain following? say my car's 35A battery is dead.

1. What is the spec for the jumper cable? (I think it shoud be able to carry alleast 35A or more)

2. What is the ideal amperage of the Jumping battery?

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Oh lawwd,does this count as DIY nowadays???....and it's copy/pasted almost word for word from elsewhere,including the photos.... http://artofmanlines...mp-start-a-car/

And on modern Alternator-ed cars you don't need to "Keep the jumped car running for at least 30 minutes to give the battery sufficient time to recharge itself"....5-to 10 mins is more than enough without revving.If you need to keep it running more than 30 mins,either the battery is dead or the alternator needs servicing.

Edited by MasterDon

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1. for a 35v battery a normal car jumper cable would be find. but its advisable to carry a jumper cable with more copper conductors.

2. Not sure about the ideal amperage but if its a 12v battery, the jumping battery has to be 12v as well

@MasterDon, feel free to move or remove the thread

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@MasterDon, feel free to move or remove the thread

Hey I'm no moderator...just pointing out some issues with your post....

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Good post for those who do not know how it's done. But posting the source would have been a better idea. :)

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I'd like to add another step to Schiffer's post...If it's an old car always check if it has a positive ground.

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Oh lawwd,does this count as DIY nowadays???....and it's copy/pasted almost word for word from elsewhere,including the photos.... http://artofmanlines...mp-start-a-car/

lol !! But at least he posted the links / source in his post...deserves a break for that.

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lol !! But at least he posted the links / source in his post...deserves a break for that.

I think he added the links after my post...Anyways it's a useful thread however it came to be.Lots of people don't know how to use the jumper cables.

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Certainly hardly anyone I have seen connects the black lead to an unpainted metal surface...even though it is clearly mentioned in the manuals as well. Haven't seen any sparks or explosions yet though.

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Adding more to this, this is my practical experience. when the battery is fully dead a simple jump start like this would not help. Even when the good car battery is fully charged (after a long trip) jumping to the dead car didn't fully cranked it. I had to swap the batteries to turn on the dead car.

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Certainly hardly anyone I have seen connects the black lead to an unpainted metal surface...even though it is clearly mentioned in the manuals as well. Haven't seen any sparks or explosions yet though.

Correct! But please keep in mind more often than not we jump start vehicles with batteries that are almost at the end of their service life (High internal resistance). Connecting to the chassis is a safer method if you are connecting to a good battery (Low internal resistance) that has gone down. Since we have no way of knowing the battery condition before we connect it is always safer to connect the ground lead to the chassis.

However, there is an important point that you may miss unless you take trouble to read between the lines in the OP. When you pick up the two leads always take one in your hand and connect (or disconnect) both ends before you attend to the other. I have seen right before my eyes what happens when someone picks up both leads in their hands and tries to sort them out while trying to make the connections.

Edited by Rumesh88

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Although not a DIY per say, I think all drivers need to know how to do his as it is as important as knowing how to change your tyres in case one goes flat. If your car can be jump started, the instructions would be there in the owner's manual as well, including the specs of the source vehicle that you should be using.

I'd like to add another step to Schiffer's post...If it's an old car always check if it has a positive ground.

I honestly didn't know that there were old cars with a positive ground. This is good info. Thanks!

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See, we are learning something :D

and even i didn't know that there were batteries without positive.

@MD - are these the 8v batteries that came with old cars?

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Some old American cars came with Positive ground connection as I know.

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See, we are learning something :D

and even i didn't know that there were batteries without positive.

@MD - are these the 8v batteries that came with old cars?

I think the voltage didn't matter much mate.Its more of a period thing.My MG A which has two 6v batteries and has a positive ground.The other MGs also has this...even the TR I'm restoring now has a huge 12v battery with positive ground oriented wiring.

Edited by MasterDon

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I think the voltage didn't matter much mate.Its more of a period thing.My MG A which has two 6v batteries and has a positive ground.The other MGs also has this...even the TR I'm restoring now has a huge 12v battery with positive ground oriented wiring.

i see, never came across a battery without a positive terminal.

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i see, never came across a battery without a positive terminal.

No no The batteries are the same normal ones,its the wiring that's different.

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No no The batteries are the same normal ones,its the wiring that's different.

ahhhh, think i understood :D

OT - this is ridiculous, so someone stalled there car today near my house and we helped to push it down the hill.. the bugger didn't release the clutch till he reached the end. -.-

its one thing to don't know how to jump start a car. but its another to don't know how to push start a car

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This might be out of the topic but With how much Amps does a alternator charge a normal 12V lets say 45ah Pb battery ? Like the Maximum Amps that a alternator is allowed lets say.

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A car alternator comes

This might be out of the topic but With how much Amps does a alternator charge a normal 12V lets say 45ah Pb battery ? Like the Maximum Amps that a alternator is allowed lets say.

For light vehicles the alternator ratings vary from 250W to 500W. A 250W alternator can supply a maximum of 20A current (250/12 APPROX.) at 2000 RPM. If you have no other electrical loads in the vehicle and if the 45AH battery is fully discharged (This, however, is not a practical situation) it will take 45/20 hours to fully charge the battery. For practical purposes we take 70% of discharge (ie 70% of 45AH, terminal voltage of 10.2V) as the maximum discharge a lead acid battery can sustain without a significant damage. But for automotive batteries repeated discharge/charge cycles to this extent should be avoided.

Edited by Rumesh88

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A car alternator comes

For light vehicles the alternator ratings vary from 250W to 500W. A 250W alternator can supply a maximum of 20A current (250/12 APPROX.) at 2000 RPM. If you have no other electrical loads in the vehicle and if the 45AH battery is fully discharged (This, however, is not a practical situation) it will take 45/20 hours to fully charge the battery. For practical purposes we take 70% of discharge (ie 70% of 45AH, terminal voltage of 10.2V) as the maximum discharge a lead acid battery can sustain without a significant damage. But for automotive batteries repeated discharge/charge cycles to this extent should be avoided.

So you are telling me if the battery has to be charged at 30Amps a 45A alternator will provide it ? There should be a maximum amperes for a pb to withstand while charging because my 10A charger charged the 12V upto 10ah in an hour.

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So you are telling me if the battery has to be charged at 30Amps a 45A alternator will provide it ? There should be a maximum amperes for a pb to withstand while charging because my 10A charger charged the 12V upto 10ah in an hour.

No. Not continuously. That is why I said it was not a practical situation. The figures i my post merely shows what to expect in theory. Batteries are able to withstand fast charging for sometime depending on the initial temperature etc. but not for a sustained period of time. Alternator is a fixed voltage device. As soon as the alternator begins to supply the battery with a charging current of 20A, there will be lot of gas bubbles forming on the cell plates thus reducing the effective cell area. This results in bringing the charging current down and terminal voltage up. Thus you will not get a constant flow of 20A into the battery for a extended period of time (Ex: 5-10min after the vehicle is started). Vehicle charging systems are designed to fast charge a battery soon after the engine is started and to maintain a float charge on long running. Although the battery capacity in a N45 battery and a NS45 battery are the same they differ in the method used to determine the capacity. While a N45 battery may be rated at 10 hour discharge rate NS45 battery may be rated at 20 hour rate and so are the charge/discharge capabilities of batteries. This is why OEMs advise you to always fix a recommended capacity battery so as to protect the alternator from overloading.

Edited by Rumesh88

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