In the digest for 19 December, Mike Thompson asked whether it was possible
to jump start, when one car had positive earth and the other had negative
earth.
The answer is yes. There is a simple check list to follow, which starts
by making sure the cars are not touching each other.
If the positive earth car has the flat battery, the steps are :
1. Connect a lead to the negative terminal of the donor battery.
2. Connect this lead to the negative terminal of the flat battery.
3. Connect the other lead to the positive terminal of the donor battery.
4. Connect this lead to an earthing point away from the battery on the
disabled car.
If on the other hand the negative earth car needs to be jump started by a
positive earth donor car, proceed as follows:
1. Connect a lead to the positive terminal of the donor car.
2. Connect this lead to the positive terminal of the disabled car.
3. Connect the other lead to the negative terminal of the good battery.
4. Connect this lead to a remote earthing point.
The usual precautions should be taken when working around batteries. Don't
wear metallic objects on your hands and wrists, wear glasses if you have
them, make sure the batteries are the same voltages etc.
Hope this helps.
John Pike
1960 TR3A
|