disconnect the battery.....

[Shield Arc]

In 2004 I bought an F-550 cab & chassis, built a 14-foot flatbed dump for it. In the up fitter's manual it said to disconnect both batteries before doing any welding. 2007 I sold it and bought a Dodge cab & chassis, bought an aluminum flatbed for it, but made the bumper, and a sub frame to attach the flatbed to the frame of the truck, again in the up fitter's manual it said to disconnect both batteries, which I did.
Now for the catch, I've done a few little welding projects on my JD tractor, never once disconnected the battery. Couple years ago I ran out of fuel, but the gauge said 3/4 of a tank! Circuit board in the dash went out. John Deere wants a $1,000.00 to replace, (yeah like that is going to happen)! So the question is, did I burn this board out by not disconnecting the battery, or just one of those things?

 

[DarkBlack]

Glad I don't buy deer- $1,000 for a dash circuit board ????
Millions of people have electronics fail, new and old- who don't weld. Amazing ehh??

 

[Shield Arc]

$1,000 for a dash circuit board ????

Yeah I about fell over!
When ever I'm welding on a vehicle, machinery, or any kind of equipment I keep the ground clamp as close as possible. I just didn't think it would hurt my tractor, but who's to say that is what happened?:confused3:

 

[pipefitter]

My curiosity was whether or not there were any electronics I would damage when I do this weld. As I said, I was told to unhook the battery when welding on a vehicle with a computer, and wondered if it was necessary on my tractor. Thanks for all the responses. BTW, that's a great looking headache rack, Shield Arc!

 

[Shield Arc]

BTW, that's a great looking headache rack, Shield Arc!

Thank you!
Would you believe when I got through with that truck, adding the hoist, hydraulic pump, tool boxes, and bumper, I added 1-ton to that truck? All it did was make it ride a little better.:laughing:
Couldn't find any pictures of the hoist, but here is one of the bumper I built.

 

[CNC Dan]

give the choice.. i'd disconnect hot before ground....

Cuts off power just the same, but if your wrench hits the body or frame you can get a powerfull arc. That's why they always say to disconnect the neg. terminal.

 

[DarkBlack]

I was waiting for someone to call BS on my #19 post, No doubters?

 

[Soundguy]

Cuts off power just the same, but if your wrench hits the body or frame you can get a powerfull arc. That's why they always say to disconnect the neg. terminal.

if I'm removing the battery, I'll disconnect the neg first, to prevent that.

if I'm not removing the battery.. i might like everything in circuit still grounded..

 

[Baby Grand]

Come to think of it, In the very unlikely event that things were done wrong to allow the welder to possibly cause issues with either the expensive electronics, or the battery, I can think of some situations where the electronics would actually be more protected by leaving the battery connected.

I was waiting for someone to call BS on my #19 post, No doubters?

Okay - I'll play devil's advocate.
Just curious how you figure that?

 

[DarkBlack]

Glad you asked!
Without getting technical I think the easiest way to explain it, is to say that the battery is parallel to all the exposed loads. Since the electronics are designed to run from the battery's voltage range, any outside influence over that range will be partialy buffered by the battery's tendency to maintain it's voltage and absorb current from higher voltages. That protection would end, of coures as soon as the fuse blew.

Here's just one example: You do everything wrong-you leave the keys on so your expensive ECU is connected to frame ground ( including all sensors ) and through the ignition switch and the fuse to the battery. You connect your welder ground to one end of the tractorand you bring the mig/stick to the other end. Now to damage the ECU you need to send current through it, so you start welding where some + wires are nearby, and you burn through the wire coating of the power lead of the ECU.
If you had the battery disconnected you now are probably puting somewhere around 20 volts on your expensive device that is destroyed above 16-18 volts. But if you had the battery still connected there would be a paralel path through the fuse to the battery. The battery would have drawn some current before the fuse blew, lowering the voltage because of the added current to the battery.

 

[DarkBlack]

I can't beleive the usual doubters are letting me get away with this one.

 

[Baby Grand]

Heck, I'm still trying to figure out what you just said.
I'm good with anything as complex as a flashlight circuit.
Beyond that I get that "what'd ya do with the ball" dog look.
Can you give me a plumbing analogy?

 

[Jesse masterson]

Would that fact matter even if you were welding on ac current, would the battery absorb ac current.since its DC

 

[Soundguy]

think about what is happening wih ac current. it simply swaps polarity.

 

[wolfpack2]

The main reason the OEMs tell you to disconnect the battery is to power down all of the electronic modules in the vehicle. A powered down circuit is much less susceptible to EM damage than an energized circuit. It is the EM radiation produced by welding that the manufacturers are concerned about.
Most people forget that there are several circuits and modules that are on at all times and just turning off the car/truck/tractor does not turn them off.

 

[DarkBlack]

Digital circuits that are still powered with the key off, are usually co-supported by an internal backup battery or storage capacitor. So if you desire to pull your battery connections, you will have to wait for the caps to discharge on those devices. The ones with internal batteries will still be live. If you're worried about EMI, You might want to think about any other elecronic device in the area.

 

[Johnp33]

I worked on Class eights, I was always taught to disconnect the batterys period both cables. I always thought it was a waste of time, then a truck was brought in with a no start condition, it had stainless boxes on the side of the deck, and a recent weld, the trucking company was not a fly by night outfit. They did a lot of fabricating, and specialty work. The ECM was fried, and the core was denied he paid, that is about a $2,800 touch, for an M11 ECM plus reprogramming and resetting all the presets, If you ever see an M11 in a FL112 you will understand why it was a 8 hour job, that was an $840.00 labour charge.
I worked at a trucking outfit and they were welding the light box on a set of triples, the "C" box and it burnt out every marker and clearance light on the three trailers. The truck was running and the lights were on.
There are a lot of rules about electricity, the bad thing is that electricity does not seem to be able to read.
I always waste my time and disconnect the batteries, good time to clean the connections anyways.

 

[k0ua]

I just got done welding my hooks on the Kioti bucket. I did not disconnect the battery. There are 2 control modules, several sensors on board this tractor. I made sure I had a good ground connection on the bucket itself. Everything still works. Not saying it is a good or bad idea.. just saying what I done, and the results.


James K0UA

 

[DarkBlack]

I worked on Class eights, I was always taught to disconnect the batterys period both cables. I always thought it was a waste of time, then a truck was brought in with a no start condition, it had stainless boxes on the side of the deck, and a recent weld, the trucking company was not a fly by night outfit. They did a lot of fabricating, and specialty work. The ECM was fried, and the core was denied he paid, that is about a $2,800 touch, for an M11 ECM plus reprogramming and resetting all the presets, If you ever see an M11 in a FL112 you will understand why it was a 8 hour job, that was an $840.00 labour charge.
I worked at a trucking outfit and they were welding the light box on a set of triples, the "C" box and it burnt out every marker and clearance light on the three trailers. The truck was running and the lights were on.
There are a lot of rules about electricity, the bad thing is that electricity does not seem to be able to read.
I always waste my time and disconnect the batteries, good time to clean the connections anyways.

Blowing lights from welding, would happen even faster if the battery was disconnected.

Welding on a running vehicle is a whole different circumstance.

 

[Soundguy]

I just got done welding my hooks on the Kioti bucket. I did not disconnect the battery. There are 2 control modules, several sensors on board this tractor. I made sure I had a good ground connection on the bucket itself. Everything still works. Not saying it is a good or bad idea.. just saying what I done, and the results.


James K0UA

my guess is that most people that damage stuff by welding fall into one of these catagories:

1, welded THRU something into a wire or caused insulation to melt from heat conduction.

2,welded thru a bearing or bushing causing a galling, distortion or seizing.

3, welded on a part that, due to ground placement.. welded thru another part or cable as a ground path, due toi an insuficient ground location they chose with t he cable