Now connect the negative black cable to the good battery negative terminal
and the other end to a body ground(engine block) of the dead car about 2 feet(60cm) away from the dead battery, this prevents any explosions.
now start the live good car and rev up its engine for a few minutes so that the dead battery gets charged
Now start the car with the dead battery and it will start up normally
keep both car engines running and then disconnect cables in reverse order
remove black negative from body ground of dead car then disconnect black negative from good battery
now remove red cable from good battery and last of all the red cable from the dead battery
run the car with the dead battery round the block for about 30 minutes for the battery to charge from the alternator
revving the car doesn't matter a bit. the alternator puts out plenty of power at an idle. I jump cars with a hot battery that's not in a vehicle all the time. some people......
doesnt matter which one you connect first. let the boosting car idle a bit (this depends on how low the dead battery is) about 5 - 10 minutes. now rev the boosting car while trying to start the dead one
The whole thing about connecting them in order is to prevent a battery explosion, so in one way it really does matter. Batteries produce hydrogen when they charge and the theory is to keep the sparks of making the last connection away from the batteries. The wisdom is that the dead battery is not producing hydrogen while the live one is because it is still charging. On the other hand, the only battery explosions I have had were from cranking the engine after the car had been sitting for hours. Anyway, make the last connection to the engine block away from the battery and remove that connection last. The rest really don't matter at all.
Motorhead makes a very good point - alternators are not meant for charging batteries and batteries are not meant to be charged by alternators, except for the short time after starting. As soon as practical you should remove the battery and charge it with a real charger.
It doesn't matter which on you connect first. As long as you connect the negative cable last (it's just good practice of prevent sparks).
And like the other guy said. It's good practice to charge up the dead battery for up to 10 minutes while car jumping keeps it at high idle (1500-2000rpm so the alternator can put out it's amps at full potential, anything higher is just a waste of gas and the voltage regulator kicks in limiting the output). This will lessen the strain on your battery.
The order does not at all matter.
But first, you should know that jump starting a car is risky.
If you do start a car with a dead battery, the chances of the car blowing its alternator once it does start, are very high. That is because a really dead battery forces the alternator to max out, and it is not built for that.
You should always take the battery out instead, and charge it up with an external charger.
But yes, you should rev the donor car up, to charge the dead battery up a little, before trying to start the dead car. Reving the engine causes the alternator to produce 14.5 volts instead of just the 12.5 volts of the battery alone. But it is also somewhat risky for the donor car as well.
So I was reading some instructions on how to jump a car battery. Some of the instructions said to connect the red cable to the dead positive battery cable, and then connect the red cable to the live positive battery cable. However, some of the instructions say to connect red to live first, and then red to dead. Does it matter what order you connect the red cables?
Also, is it necessary to rev the engine on the live car before you try the dead car?
