Welding question ...

[blueriver]

I have welded a little over the years, not professional. My beads sometimes look good and then other times WELL ...

My question ... I was told yesterday that anytime I am welding on a vehicle or a piece of equipment hitched to the tractor I must unhook the battery negitive post to avoid damage to the vehicle/tractor altenator, charging system and or the computer system.

True or False ...

 

[Scooby074]

Personally, I do it. It only takes a few seconds to disconnect the battery. There are opinions all over the place as to whether or not it actually does anything, for the time it takes, ill do it and err on the side of caution. You should also connect the ground from the welder as close as possible to the place your welding and ensure good ground contact.

There are devices available that connect across the battery to prevent damage so you dont have to disconnect the battery and reset the clock/radio.

 

[WantedWolf]

I do it on newer trucks with fancy electronics but never on my 80's toyotas

 

[2manyrocks]

True. Why take a chance? I have a pricey rectifier on my Yanmar that I never want to replace again.

 

[Iplayfarmer]

I know that the chassis of every fire truck in the district has a sticker on it somewhere warning to disconnect the battery cable before any welding. Because of that I disconnect the battery anytime I'm welding on a vehicle. I'm with Scooby and 2manyrocks... It's not a big deal to do it, and it could save a lot of trouble.

 

[jimmer2880]

Personally, I do it. It only takes a few seconds to disconnect the battery. There are opinions all over the place as to whether or not it actually does anything, for the time it takes, ill do it and err on the side of caution. You should also connect the ground from the welder as close as possible to the place your welding and ensure good ground contact.

There are devices available that connect across the battery to prevent damage so you dont have to disconnect the battery and reset the clock/radio.

I used to work at a tow-truck/rollback mfg shop. They used those devices a lot. UNTIL one of them failed & they fried the computer. After that, the owner inisted that they disconnect the negative.

 

[Skyco]

In some of the official Ford manuals they not only say to disconnect BOTH battery terminals but some of the connectors on the various PCMs even the instrument cluster modules and ABS computer.
I would imagine welding EMF damage could be a lot like ESD damage- the vehicle could be fine after welding but then die months down the road because a semiconductor junction was weakened during the welding then fail later. Very expensive stuff to replace some of those PCMS/modules.

 

[Flatheadyoungin]

newer computer stuff is VERY sensitive....

older stuff, i'd disconnect but not be as worried.....just depends on what it is...

like has been said, a good rule of thumb is just to disconnect....the 30 seconds it takes might save a lot of $$ and time later...

 

[WantedWolf]

How about we ask the weldors with mobile rigs how many times they disconnect thier truck batterys when welding on thier service decks?
I cant personally think of 1 to start the list

 

[Scotty370]

Oh sure Wolf! Get logical on us! (But I'm in favor of the 'disconnect')

 

[john_bud]

How about we ask the weldors with mobile rigs how many times they disconnect thier truck batterys when welding on thier service decks?
I cant personally think of 1 to start the list

There is a difference between welding on a work surface and welding part of the truck. Plenty of computers and electronics have died from voltage spikes caused when welding. Many more did not die. I don't know why one dies and one lives. But, how many mobile welding service people have been sued and lost for not disconnecting the batteries?

I've also seen bearings that were arc welded from current path issues when the ground was put on in the closest spot.

jb

 

[WantedWolf]

Heat transfer aside I dont see any difference in welding on the flat deck or welding on the front bumper of the same pickup. Welding decks would be grounded to the frame better that most pickup boxes.

if the ground was placed close to the welding point, which was close to the bearing, which was close to where the welding was done then I would suggest it was heat that caused it to sieze not the electricity were concerned with here for ECM's etc.

I dont know them all but I have never heard of a single mobile weldor being sued for not disconeccting batteries.

Heat transfer aside, electrically speaking I dont see any difference in welding on the flat deck or welding on the front bumper of the same pickup. Welding decks would be grounded to the frame better that most pickup boxes. If you can fry it, it would be fried from a close or far connection on a 20 ft truck. no?

 

[Wheatland KB]

I've also seen bearings that were arc welded from current path issues when the ground was put on in the closest spot.

jb

I am always wary of bearings and loader pins etc... but usually just make sure that the ground is as close to the weld as possible. I have never had any problem with any electronics but would be leary on a newer vehicle.

One more thought on bearings, can they not be magnetized by current flow! Last thing you want is a bearing to be a big magnet

KB

 

[towmotor]

I always disconnect the batteries and the ECU when I have to weld on my truck or car.
The things are just too expensive to take the chance.

 

[Inkomodius]

Definatly pull the negative, and if your doing tig welding with high freq start, pull both terminals and keep your ground as close to the weld as possible. I have watched the entire electrical system on a kenworth be replaced at a cost of 25 grand and the electrical system on an 06 GMC duramax replaced as well all do to people not disconnecting the negative. From what ive learned its similar to people running sensitive AC equipment off a generator that isnt putting out true 60 hertz. Like a PBX telephone system running off a messed up generator that is putting out 30ish hertz gets realllly expenisve.

As far as welding trucks are concerned, any of mine have been isolated from the trucks electrical system. The welder its self is isolated or if the deck is grounded then the deck is isolated. All in all people can get away with it but it aint worth the chance. Hindsight is 20/20 and for the few seconds it takes do it.

 

[Skyco]

As far as welding trucks are concerned, any of mine have been isolated from the trucks electrical system. The welder its self is isolated or if the deck is grounded then the deck is isolated.

That is mentioned by Ford as well. Here is the link to their bulletin-
https://www.fleet.ford.com/truckBBAS/non-html/Q123R1.pdf

I'm not much of a gambler, I'll ALWAYS disconnect the battery when welding on MY stuff and I don't weld on other peoples stuff....just glad my truck is pre-2005 after reading all the precautions in the linked TSB above.

 

[greenmule]

Well,the older rigs I've used the circuit wasn't isolated in any way.Never heard of any troubles,but this was before computors and such.
Maybe it has something to do with dc current verses ac,all rigs that I know of produce dc current as a welding output.So it would be a dc circuit running around not ac. [I am not a mecanic or an electrician],but just a thought.

I ,the very few times I have had to weld on a tractor or vehicle,lately that is,always disconnect the neg on battery.

But yeah,always put ground as close as possible,never have ground on one end and weld on other for sure.
Electricity is still kinda a mystery to most [including me] than you add computors in that mix,and its really like witchcraft.

Best thing to do is don't weld on newer things,take part off [if you can],make it and bolt it back on,that would be the safe way.
Made a brush guard for my kioti,it would have been easier to tack a few items to tractor for fit,but I didn't,made it all off tractor than bolted it on.

 

[ray66v]

If we were repairing a vehicle, the battery was often removed as part of the repairs. In cases where it was not, we never disconnected the battery to mig weld, or spot weld. That had to be thousands of vehicles, no problems.

 

[john_bud]

Well,the older rigs I've used the circuit wasn't isolated in any way.

Never heard of any troubles,but this was before computors and such..

Ha! you made me chuckle! Naturally, if you were working with non-computerized equipment, there would be no computer damage!

jb

 

[greenmule]

Well,they still had wheels,wooden ones,but.

But seriously folks,they still had an electric circuit,points,regulators,little things full of tiny wires,etc.,and do believe many even back in the day,disconnected battery.

And,like I said,you would think even if you disconnect the battery on these new things,there would be a way welding circuit could enter at least one of these parts in the circuit? Motors have rubber mounts,but... If the circuit is going down frame of vechical,anything that touches anything that touches metal frame,could be in that circuit.

AC/DC,now dc has got high amps low volts right compared to ac which has high volts low amps,right?? I'm thinking that might have something to do with this? In one way or other,which I don't know the other. Like I said,I try not to do it,and if I do,I dissconnect battery,my point maybe is,does it really do any good to disconnect battery?

I remember years ago,when I didn't value my life near as much as I do now,jumping cars and trucks with a 200 amp lincoln,remember[think it was last one I did this too,yeah beer was involved],that their starter was actually bad,causing it to really need a bunch o juice to get it started,well,I had a buncho juice,so turned it up, and actually saw the battery expand,got it started though,no lie.
Point is a dc welder is just a big battery charger,can you use a battery charger on these new things?,think so, so..if you can use a battery charger[yeah I know,it would be lower amps than welding]...but.

Now,what about ac welding,less chance of harm,or more?