What is the proper way to jump start a car from another car?

Question

What is the proper way to jump start a car from another car?

Answer 1

All vehicles sold in the US since the late 40's are negative grounded. Only a few pieces of equipment sold worldwide are positive ground. On a typical set of jumper cables there is a black handle and a red or yellow handle on either end. With the ignition off on both vehicles, open the hood and locate the battery and the positive side terminal. connect the red or yellow lead ends to this post.( be carefull not to touch this end to any other metal parts on the vehicle) Connect the black lead(ground) to the negative terminal or to any exposed metal surface on the frame of the vehicle being charged. On the vehicle doing the charging connect this lead to the battery itself. Start the vehicle doing the charging and let the battery charge for 5 to 10 minutes then start the vehcle being charged. During this process you want to keep an eye on the cables and connections to prevent sparks or overheating the cables. Listen to the engine as well for a dragging sound or for a popping noise as this can indicate that your leads are reversed. (reversed leads can set fires or in some cases detonate the battery, Usually only if the vehicle doing the charging has an extreamly large battery system) As soon as the vehicle being charged is started remove the ground from both vehicles then remove the positive side clamp. A side note: some vehicles require the ground to not be attatched to the battery to prevent damaging the engine controle systems. Check the owners manual for this.

Answer 2

The reason why you connect the battery cables to the dead car battery first is you have 3 metal cable ends dangling and potentially touching metal car parts, so a dead battery is less likely to cause any sparking, since it has little or no voltage.

So that is the safest starting point for your jumper cables. The 2nd battery cable clamp goes to the positive end of the good battery instead to minimize completing any circuits until we are ready to.

Then the 3rd end of the battery cable goes to the ground of the good battery.  Remember, we still have not completed the circuit yet, until the 4th battery cable clamp is attached to ground.  

This is why this order of attaching the battery cables to your car batteries is the safest way to do it. It minimizes unnecessary sparking until the charging circuit is completed.

  This is good practice because excessive and unnecessary sparking could cause car batteries to fail.

Since the bad battery is weak, and to prevent exploding, it's ground clamp gets connected last, but not directly to the ground battery post.

To prevent sparking directly on the battery, you connect the 4th battery cable clamp to a metal frame part of the dead car, which is connected to the minus pole of the battery. Many people are easily confused by this step.

They cannot figure out how this completes the circuit to the battery.  Car batteries have their ground cable also wired to the chassis of the car, so by clamping to a good metal chassis point, this is electrically equivalent to connecting to the ground post of your car battery.

Answer 3

1.  Positive (red) cables to positive posts on both batteries..

2. Negative (black) cable to to negative post on donor battery

3. Negative cable to engine block on car with dead battery (Be sure your cables don't get caught up in the radiator fan or belts.)

4.  Let the battery charge for a few minutes, then go ahead and attempt a start.

Remove cables in the reverse order of connecting them, and stay clear of moving parts!

Answer 4

First be sure both vehicles are of the same voltage.

TURN OFF all electrical loads of the dead car. (lights, heater, radio, any accesories. This is a very important step that most experts even neglect to mention).This is done to prevent excessive current draw during cable connecting process.

Turn ignition of dead car to "OFF".

Be sure you have a cable of adaquate length and ampere ratings. (the dollar stores' cables act more like fuses).

If feasable clean all batery terminals and a METAL spot of the dead car. (you don't want resistance).(some new cars have a designated spot for this purpose). Avoid any moving engine parts or electrical parts, such as alternator. A good spot could be the place the hood latch goes in. The idea here is to keep away from the NEGATIVE post to prevent stray sparks.

START good car, if not already running, be sure cars DO NOT touch each other, but so close as for cable reaching.

FOR SAFETY, ALWAYS follow these steps exactly:

1- Connect POSITIVE or red (or yellow) to DEAD battery.

2- Connect POSITIVE or red (or yellow) to GOOD batery.

3- Connect NEGATIVE or black to GOOD batery.

4- Connect NEGATIVE or black to dead car's METAL area.

A small spark may be created, BE CAREFUL.

Allow cars to be connected in this manner for about TEN to FIFTEEN seconds to allow the DEAD battery to equalize.

START the DEAD car.

Allow cars to stay connected to let the boosted car CHARGE.

30 seconds to one minute is almost always satisfactory.

DISCONNECT the cables in the OPPOSITE order they were connected, (ie 4-3-2-1).

GOOD LUCK and happy jump starting.   --IC

Answer 5

First you must know whether each car is positively or negatively grounded.  Your owners manual will tell you the proper method for your own vehicle.  Be sure to read it.