Disconnect Before Welding

[Ant-t]

I alway disconnect both batterys, starter and leisure, I also earth as close to the work area as possible. I haven't had a problem with frying the ecu or alternator but I've heard of people disconnecting these as well. What do you do?

[bigbadbob76]

Same as you, disconnect both batteries and clamp near the job.
Although I have forgotten once or twice in the past and never had a problem.
Better safe than sorry though.

The way I understand it, current is induced in the wiring by transformer action, as such it will only happen if the secondary circuit is closed, hence disconnecting stops it happening as the current can't flow in an open circuit.
The induced voltage doesn't seem to cause problems.

[Ant-t]

Yeap agree with that, I think disconnecting other electrical parts possibly applies to newer vans with more advanced and maybe less robust electrics

[dbz864]

i dont bother, never had a problem

[kit]

I never disconnect the battery and not had any problems.

[boatbuilder]

I know a guy who lost an eye when a battery exploded as he was welding. He has a glass eye now that he can pop in and out!

Sent from my SM-G920F using Tapatalk

[bigbadbob76]

I know a guy who lost an eye when a battery exploded as he was welding. He has a glass eye now that he can pop in and out!

Sent from my SM-G920F using Tapatalk

Sorry to hear of anyone losing an eye.
Food for though-
Don't weld close to a battery, remove it first.
Think twice before welding in the engine bay.
Wear a face mask when welding, it protects your eyesight in more ways than one.
Don't use batteries as emergency welders, they can warp/split/vent violently/explode if you short them out.

The more usual problem with not disconnecting the battery when welding is that the induced current blows the alternator diodes.
I think you'd have to be get your welding cables pretty close to the battery/alternator wiring to induce enough current to do any damage,
hence why many folk get away with it and occasionally someone doesn't.

[jamesc76]

I have had vans and cars for repairs then had been welded and the ecu blown, battery hadnt been disconnected. You can buy a surge protector that goes across the battery and stops any damage, I have one and they work well, mine has a warning led on it to show if there was a spike and its often illuminated!

[bigbadbob76]

I have had vans and cars for repairs then had been welded and the ecu blown, battery hadnt been disconnected. You can buy a surge protector that goes across the battery and stops any damage, I have one and they work well, mine has a warning led on it to show if there was a spike and its often illuminated!

Sounds worth having James, could you post some details or a link to where you got it?
Thanks.
BBB.

[ZsZ]

I lost an alternator due to welding, so since that I disconnect the alternator wires too.

[bigherb]

Yep I also disconnect the alternator and pop out the fuses for the radio.

[jamesc76]

I have had vans and cars for repairs then had been welded and the ecu blown, battery hadnt been disconnected. You can buy a surge protector that goes across the battery and stops any damage, I have one and they work well, mine has a warning led on it to show if there was a spike and its often illuminated!

Sounds worth having James, could you post some details or a link to where you got it?
Thanks.
BBB.[/quote


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