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Electronic damages by welding
xico_ze54 - 3/11/14 at 01:59 PM

hi

several times I heard about welding in a car could damage the alternator, therefor is better unplug the alternator unless it could be damaged.

is that true? I already had a bad story in wich I got an alternator damaged and it was some time after was made a welding in the exhaust tube.

and in the motorbikes is the same? in case of yes what wires we have to disconnect?

thanks
Amadeu

adithorp - 3/11/14 at 03:38 PM

Never had it happen but it can and also voltage spikes from welding can also fry ECU's. Best to fit a surge protector accross the battery first.

I have seen a few fried ECU's from customers connecting jump leads the wrong way (one car did 3 different control units) and even them connecting the right way can cause voltage spikes. All our jump leads at work have surge protectors on them.

xico_ze54 - 3/11/14 at 04:20 PM

quote:
Originally posted by adithorp
Never had it happen but it can and also voltage spikes from welding can also fry ECU's. Best to fit a surge protector accross the battery first.

I have seen a few fried ECU's from customers connecting jump leads the wrong way (one car did 3 different control units) and even them connecting the right way can cause voltage spikes. All our jump leads at work have surge protectors on them.

thank you for your answer. but I didn't full understand what is the best way to securely make a weld? since you said even with the surge protection cannot be sufficient.

I ask: if we disconnect the battery it makes any kind of protection? or the best we can do is disconnect all the electronic devices from the frame?

the job I have to make is this: I have to weld a motorbike exhaust pipe with the manifold and of course I'm afraid to damage something. to disassemble all the stuff also is a non-wanted job.

any practical ideas? (also I have no surge protectors)

thanks

whitestu - 3/11/14 at 04:30 PM

I always understood that disconnecting the battery would prevent any issues, but most of my welding has been done on older cars with basic electronic ignition rather than ECUs.

I've never had any problems though even when I didn't disconnect the battery.

Stu

adithorp - 3/11/14 at 04:35 PM

As I have a surge protector I never have to do anything else, however have always been told disconnecting the battery earth/negative is enough.

Plenty of surge protectors for sale on the net like this...
http://www.keykingsupplies.co.uk/surge-protector-for-welding-12v24v-738-p.asp

xico_ze54 - 3/11/14 at 04:36 PM

quote:
Originally posted by whitestu
I always understood that disconnecting the battery would prevent any issues, but most of my welding has been done on older cars with basic electronic ignition rather than ECUs.

I've never had any problems though even when I didn't disconnect the battery.

Stu


I just finished to made a call to an electrician and he said just that: since one disconnect the battery all the electronic stuff is protected. but he even did know abou those surge protectors. I must confess also I didn't know, but I made a quick search and saw a lot of those and understand its job.

xico_ze54 - 3/11/14 at 04:42 PM

quote:
Originally posted by adithorp
As I have a surge protector I never have to do anything else, however have always been told disconnecting the battery earth/negative is enough.

Plenty of surge protectors for sale on the net like this...
http://www.keykingsupplies.co.uk/surge-protector-for-welding-12v24v-738-p.asp


if the battery disconneted is enough I'm happy with that. the bike already has no battery. so if its automaticly make the electronics protected I'm very happy

just don't want to make mistakes that costs money for nothing!

02GF74 - 3/11/14 at 07:31 PM

I think i killed the regulator on my land rover after welding. I always remove the alternator and unplug the lumenitio now as a precaution.

Davey D - 3/11/14 at 08:26 PM

Disconnect the battery, unplug the ecu, and put the earth clamp for the welder as close as possible to what you are welding to help reduce chance of damage from stray currents

Mr Whippy - 4/11/14 at 12:21 PM

haven't managed to break a car yet but it is always a good practice to have the clamp lead as close to the weld as possible just in case some of the current of which there is an awful lot flows through a wire due to a bad earth in the bodywork, in theory it's like lightning strikes and should pass round the outside of the car to the point of welding but perhaps not always, it's a good idea to remove the battery anyway due to the gas off them. Most alternators take seconds to disconnect anyway.

coyoteboy - 4/11/14 at 01:07 PM

Clamp lead as close as possible, disconnect battery neg and you'll be fine, but my normal process involves disconnecting anything I can't afford to replace easily. For the sake of 5 minutes.

02GF74 - 4/11/14 at 06:58 PM

^^^ wot c boy said, its a faff but cheaper and less time consuming if somethimg goes pop.