Welding & vehicle electronics

[INFChief]

I’m watching a YouTube vid where a guy is fabricating a CL III hitch. He brought up, and should the warning label on the vehicle) where the batteries need to be disconnected (and maybe a couple of other precautions taken) otherwise electronic component could be damaged.

Sounds plausible but I’m curious if anyone has encountered this?

 

[Guruman]

I've always considered this a bit of a myth, sort of like how people believe that cell phones cause fires at gas pumps.

I can see how passing welding voltages through you car's electronics would fry things. But I'm always welding on things mounted to the frame. The electrical path between my gun and the ground clamp, doesn't run through the ECU. I suppose if you are welding on the body, with a ground clamp on the frame, you might cause an issue, but why do that? Keeping you ground connection near the weld area seems like best practice anyway.

I can also see that at high current rates, the welding might generate a large electromagnetic field, which might cook the ECU or some other sensitive electronics. Maybe that's what is happening. Disconnecting the battery might prevent any induced voltage from flowing to ground and possible save the sensitive electronics. Maybe?

Interested to hear what others have experienced.

 

[Keith Knight]

I’ve welded on my LMTV many times along with welded on many other vehicles and equipment never disconnecting the batteries, sometimes even when the tractor is running. Never had a problem with electronics. Just be careful what’s on the other side of where you’re welding because the heat will definitely welt the wires!

 

[chucky]

I have probably burned 75 pounds of rods on my truck lol and i always take the 12 and 24 v cables off the altenator and the main 12 + and 24 + in the battery box ! i keep my ground clamp close to where im working but im paranoid that i might fry my altenator and it doesnt take 3 min to insure success .

 

[Mullaney]

I’m watching a YouTube vid where a guy is fabricating a CL III hitch. He brought up, and should the warning label on the vehicle) where the batteries need to be disconnected (and maybe a couple of other precautions taken) otherwise electronic component could be damaged.

Sounds plausible but I’m curious if anyone has encountered this?

.
Just guessing here, but the old trucks that I once worked on that had electrical - not electronics - were welded on without a thought about disconnecting the battery cables.

In todays vehicles, it would seem possible for a poorly connected welding ground to "Zap" an electronic TCM or Tachometer or any other electronic truck part. Just that first strike of the arc where the electrical surge is looking for ground to complete the circuit might find and cook expensive truck parts.

 

[INFChief]

.
Just guessing here, but the old trucks that I once worked on that had electrical - not electronics - were welded on without a thought about disconnecting the battery cables.

In todays vehicles, it would seem possible for a poorly connected welding ground to "Zap" an electronic TCM or Tachometer or any other electronic truck part. Just that first strike of the arc where the electrical surge is looking for ground to complete the circuit might find and cook expensive truck parts.

I would not want to take a chance. I’m curious if you know if any of the electronic stuff (ECM, etc) have internal batteries to store memory and keep the component “active” even when batteries are disconnected?

 

[INFChief]

I've always considered this a bit of a myth, sort of like how people believe that cell phones cause fires at gas pumps.

I can see how passing welding voltages through you car's electronics would fry things. But I'm always welding on things mounted to the frame. The electrical path between my gun and the ground clamp, doesn't run through the ECU. I suppose if you are welding on the body, with a ground clamp on the frame, you might cause an issue, but why do that? Keeping you ground connection near the weld area seems like best practice anyway.

I can also see that at high current rates, the welding might generate a large electromagnetic field, which might cook the ECU or some other sensitive electronics. Maybe that's what is happening. Disconnecting the battery might prevent any induced voltage from flowing to ground and possible save the sensitive electronics. Maybe?

Interested to hear what others have experienced.

You make some good points. I think I will disconnect my batteries if I do any welding - just to be safe. Like I asked Mullaney above, what about components that have internal batteries that keep memory alive when the primary power source is disconnected?

 

[Keith Knight]

Yes the ECM has a battery in it, I know because when it the battery in my ECM died I had to pay Caterpillar a lot of money for a new ECM and for them to reprogram it. When it happens it it causes a crank and no start situation.

 

[Keith Knight]

Disconnecting the positive on the battery does nothing. If that theory is correct then you have to consider that everything is DC which means a positive and negative is required for all the electronics and if you don’t remove all the negative ground points to all the electronics there is still a pathway for the voltage to travel. But it doesn’t actually do that. Its traveling from ground clamp to electrode. Just don’t clamp the ground clamp to you ECM! LOL!!!

 

[Ronmar]

I have welded on lots of stuff over the years and never damaged any installed electronics. I associate with quite a few people who do the same thing and have never heard of anyone damaging any electronic component. Thats my experience anyway…

As mentioned, my ground is always where I am welding, not at the other end of the vehicle. Also typical welding voltages are not all that great. it is not a bolt of lightning, it is a low voltage localized circuit you have created. The main wire feed welder I use runs around 36V. Most welders are not very high voltage because it creates a safety hazard for the welder.. Now if you float the chassis to 36V and any accessory is turned on, that 36V can be felt on the DC buss, but disconnecting the batteries will not prevent this. And since the chassis is already at the same potential, there can be no real current flow. I see that as the same situation as the chassis being at any other potential…

now electrostatic discharge can damage components, but that is usually while working INSIDE the case of the component. The case design shields them, if it did not, we would kill them simply unplugging them or moving them around, and that does not happen. I have swapped a lot of them and even built some megasquirts and never damaged one…

 

[chucky]

When i was doing all the heavy welding on the dovtail on my truck im in 1/2 thick metal grounded up close but super hot n sweaty days with the miller up on 80 amp burning heavy rods. Depending what part of the truck im laying on or in i would get nipped pretty good some times so i figure if its getting me some of this voltage is making it to other things as well .

 

[Ronmar]

Well you were getting bit because you were holding half of the welding circuit in your hand and completing a circuit to ground with your hand on the stinger and some other part of your body to ground…. Wet sweaty hand on dirty damp stinger and sweaty skin on the frame…

ever been shocked while standing next to someone who is welding?

 

[chucky]

Well you were getting bit because you were holding half of the welding circuit in your hand and completing a circuit to ground with your hand on the stinger and some other part of your body to ground…. Wet sweaty hand on dirty damp stinger and sweaty skin on the frame…

ever been shocked while standing next to someone who is welding?

Im wearing thick leather welding gloves halfway up my arms i would usally get it thru my carhart t shirt of coarse dripping wet with sweat but i would have to lay or hang over other bare steel already put in place off the ground . I salted and drove a 8 ft ground rod by the truck and tie my welder ground to it then another ground clamp to where im burnin rod from there . Its like its still seeking more ground than the ground cable can bring it ???????????

 

[Ronmar]

Well next time you get bit, stay in that spot, and hand the stinger to someone else and let them burn a little. I doubt you will get a shock… old dirty glove damp with sweat? What kind of welder, any high freq? This DC or AC stick?

 

[chucky]

Well next time you get bit, stay in that spot, and hand the stinger to someone else and let them burn a little. I doubt you will get a shock… old dirty glove damp with sweat? What kind of welder, any high freq?

 

[chucky]

iTS A MILLER 330 A B It has a high freq switch and reverse polarity AC/DC TIG/STICK

 

[MD3070 LMTV]

Well next time you get bit, stay in that spot, and hand the stinger to someone else and let them burn a little. I doubt you will get a shock… old dirty glove damp with sweat? What kind of welder, any high freq? This DC or AC stick?

I have 47 years welding experience .

1) Getting zaps through your body when welding has killed around 18 people that i recall reading about in OSHA style investigations , The most common way is having wet or damp clothing or gloves , when your body touches the job and you have the stinger in your hand , that little zap of electricity through your chest upsets your cardiac rhythm , Guys have dropped dead on the spot , and some died from heart attack which occurred up to 12 hours later , There was also cases near me where the guy died because he put the stinger under his arm as a third hand while he moved into another position or picked up something else , his damp armpit completed the circuit to ground where his body was touching the job.

2) We pay money for battery spike protectors because they work , they clip on to the battery terminals during welding so we dont blow up ECU's , damage batteries , or damage load scale devices , or you can just disconnect the battery negative.

3) If welding on Mil-Spec trucks they are mostly HEMP hardened so nukes dont kill them , You have less chance of damaging the electronics when welding on one of these but why take the risk ? just take off the battery terminal or fit a battery isolator.
I have a battery isolator on every vehicle i own and wouldnt have it any other way.