Welding...on a truck....

Sparktrician · Jul 24, 2008

If you weld on a vehical, or anything w/ a charging system, i have always been told to disconnect the battery, so not to damage the charging system. I you were to connect the ground of your welder to a point as close as possible to your welding spot, will you still damage the charging system???

CumminsMan · Jul 24, 2008

Yes, has also been known to blow fuses and radio. Just easier to disconnect the battery.

Anonymous-0 · Jul 24, 2008

Electricity is like college students, it will take the path of least resistance. So in your case if you are dang sure that it will take the path you want it to then go ahead. I would disconnect the battery and anything else that I thought had a remote possibility of being the improper conductor. I took a shortcut once and the welder took the path through some very expensive electronics. It was over in a millisecond and nothing was left but smoke.

larry cook · Jul 24, 2008

have always heard the same, disconnect the battery. yet, i know welders that have been in the business over 30 years and have never disconnected the battery. go figure.
larry cook

old · Jul 24, 2008

I weld stuff all the time and never unhook the battery and so far never had any problems. Ya its a good idea to unhook the battery but I don't 99% of the time
Hobby farm

Anonymous-0 · Jul 24, 2008

The most important thing is where you install the ground clamp in relation to where the weld is being made.........Vehicles/equipment without computer controlled engines, transmissions, hydraulics, etc. are not likely to experience ill effect from welding repairs BUT it CAN happen..........Vehicles/equipment with on board computers are a different story, some people will unhook the battery under the assumption that doing so will protect the computer. That is not entirely the case, computers can still be damaged from improper grounding procedures during welding unless all wiring harnesses to those computers are physically disconnected............

The bottom line is to have to the ground clamp absolutley as close as possible to the area being welded and to ensure abundant amounts of common sense are applied during the entire procedure..............

glennster · Jul 24, 2008

took a class a couple months ago for our shop certification. that subject was addressed during the course. their take in the deal is to keep your welding cables perpendicular to the vehicles, not parallel along the vehicle. the explanation they had is the welding cables generate an electrical field and if parallel to the vehicle will create voltage in the vehicles wiring. im not an electrical whizz, so maybe john t can chime in on this one.

jose bagge · Jul 24, 2008

I weld on vehicles all the time- almost every day- and never disconnect the battery. I have never had an issue....

T_Bone · Jul 24, 2008

Hi Sparktrician,

They way I've always looked at it, is that it may take 5min to disconnect the battery(s) but upwards of a $1000 plus another couple hours replacing parts if murffy shows up.

Along with keeping the ground clamp close by the weld zone, make sure your welding leads are not coiled around anything as this too will do as much damage if not more.

T_Bone

Roy Suomi · Jul 24, 2008

NAH...I weld on my truck all the time..Thaw water lines , You name it..But of course my '78 Ford F-600 barely has an electrical system..Maybe the newer trucks with electronics galore is another situation..Computers get real testie around errant voltages..Truck body installers are constantly unhooking computers and batteries on new installs..

Anonymous-0 · Jul 24, 2008

most idiots don't

Mike M · Jul 24, 2008

Our body shop had a bad experience with this on a pretty new Ford truck. Tech says he unhooked the battery , but still the computer and several other modules were damaged and had to be replaced.
Had a similar thing happen to a Catera sent up to a local exhaust shop for a converter replacement. Came back with radio not working. Don't know if battery was unhooked or not , but end result was it needed a new radio.

So on something new I'd be safe and unhook both battery cables and even unplug the modules or else you could be facing BIG bucks for replacements !

old · Jul 24, 2008

Now that is un called for. I have been welding probably longer then you have walked and if not then you are older then I am. I'm a retired electronics tech so I know about electric circuits. At one time I did computer repair for a living and have done welding machinics, and lots of other things so I have been around the block a few times

old · Jul 24, 2008

Thats one of those where you unhook both cables from the battery then ground them both. That way no power can be across the computers or any thing else. Yep I was an E-T in the navy and we even grounded our body when working on computers because back then there where circuits that would fry just by you touching them with your hands
Hobby farm

showcrop · Jul 24, 2008

My 2003 truck has very emphatic instructions in manual to disc. ground before welding on it. it also has a lot of electronics.

JOB · Jul 24, 2008

On vehicles with an alternator I would disconnect the ground. On vehicles with all this electronic garbage I would not even weld on them. With my luck if I even thought of welding on them my electronics would be messed up. On the older Tractors with a generator do not weld on them with an AC machine. You will depolarize the generator. I did that on a 57 ford truck and a 56 Allis. And I know 2 people who no longer have a working DC welder because they welded on the frame of the machine with an AC buzz box. One of those guys did get several DC batteries and hook them in series and polarize his generator. Thats my 2 cent's worth

MarkB_MI · Jul 24, 2008

I don't think there's any doubt that welding can damage electronics. In particular TIG welders that use high frequency start can cause a problem; I've heard that TIG shouldn't be used on a modern car for that reason.

HOWEVER, I don't understand why disconnecting the battery should do anything to prevent damage. If anything, leaving the battery in the circuit should protect electronics from high frequency spikes. The battery looks like a big short circuit to any spike on the battery cables. Short of tieing the disconnected battery cables together as Old suggests, I can't think of a better way to protect the electronics than to leave the battery hooked up.

trucker40 · Jul 24, 2008

Well I have welded stuff on about everything from motorcycles to tractor trailers and not unhooked a battery cable yet because I was welding on it.I dont think its a big deal,but I dont know everything either.I go to a muffler shop when I need work done on my exhaust,been going to the same place for over 30 years.Never saw anybody there unhook a battery cable.Now it might be a good idea to unhook them.Untill I read this Never thought about it much.I worked on TVs years ago,and you can fry electronics by hooking it up wrong.Ill say this,I dont think you should weld in the area of the dash or where a magnetic field from the welder would be close to the computer.That maybe would be bad for a computer.I guess I dont see why welding on its own,away from the computer some where the magnetic field from the welder is away from it,would affect it?Especially if you hook the ground close to where you are welding.I could be wrong.

dave guest · Jul 24, 2008

Had a 77 ford van, never ran too good. Went to sell it and side sliding door fell off. Fella buying said weld it in place and be okay. When I struck the arc something cracked and popped real loud under hood. Sucker ran so good I wanted to keep it. Story #2 when I worked in auto plant, weldor had to work on automation equipment. Said he knew what he was doin'. Finished his welding, and every piece of sealtite on fixture was fried. Took over 4 hours to replace all of that. Was told he should have placed ground close to each weld. Funny but I am the sparky that had to stay over and make all corrections. I would be darned careful welding on auto.

Anonymous-0 · Jul 25, 2008

There has to be a very large voltage pulse whenever a welding arc is struck.A welder is a large inductive circuit with an 80 volt open circuit.The pulse will happen when the arc is broken for sure.A 6v ignition can generate a 200 volt pulse when the points open,ever been shocked when opening points by hand.You would have to watch the arc voltage on an oscilloscope to prove the actual voltage present when the arc is broken.If a 6 volt ignition can produce a pulse that is 33 times higher, could a welder at 80 volts.produce a 2680 volt pulse?This would eat solid state devises.Welder diodes have rc network to protect them from hi voltages.Weldors have been warned to keep their bodies out of the welding circuit.Not an engineer,just a fellow who started working in electtonics in 1950.

Anonymous-0 · Jul 25, 2008

I disconnect the battery and alternator..better to be safe than sorry.

Welding...on a truck....

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