Thread: welding while attached to car

Originally Posted by V8Ian

I used to use this method in preference to disconnecting four batteries, would not be prepared to risk it on any vehicle with even the most basic of electronics/computeritis.

i used to disconnect batteries all the time, well still do when at work, but after talking to techs at exhaust shops....who never disconnect no matter what model i am comfortable not disconnecting

Originally Posted by weeds

i used to disconnect batteries all the time, well still do when at work, but after talking to techs at exhaust shops....who never disconnect no matter what model i am comfortable not disconnecting

Don't these guys use some sort of spike arrestor, bridging the battery?

Originally Posted by weeds

i used to disconnect batteries all the time, well still do when at work, but after talking to techs at exhaust shops....who never disconnect no matter what model i am comfortable not disconnecting

True - but their earth is always connected direct to the exhaust close to where they are working. The point is that the current will take the shortest possible route, and if it can go direct thru the part being worked on it won't affect the rest of the car. A good earth, close to the area being welded, is the key.

Willem

DC welding is ok without dropping earth...

I still disconnect out of habit.

If you can get one get someone to hook up a crow to the alternator output and the body of the alternator and watch what happens when you weld on something.

Originally Posted by Blknight.aus

DC welding is ok without dropping earth...

I still disconnect out of habit.

If you can get one get someone to hook up a crow to the alternator output and the body of the alternator and watch what happens when you weld on something.

It'll probably sit there and peck at the fuse box.

What does the cro show?

wierd spikes.

I used to be in the "nahh thats banana poo crowd, the current goes from the welders tip or electrode to the earth cable"

Its not huge voltages from memory maybe 5 v either side of 0v, I think (and my electronics is very rusty) that its the volts going to the negative side of 0 that cause damage to either the diode pack or the regulator side and the big problems occour not at the time of welding but when you fire up the engine and the alternator starts trying to work again.

Originally Posted by Blknight.aus

DC welding is ok without dropping earth...

I still disconnect out of habit.

If you can get one get someone to hook up a crow to the alternator output and the body of the alternator and watch what happens when you weld on something.

You mean CRO, not CROW as in Cathode ray oscilliscope?

Not the black buggers, that you never see dead on the road

no I mean a CROW...

Cathode Ray Oscilloscope, Working.

as opposed to a CROB.

Cathode Ray Oscilloscope, Broken.