Any point in disconnecting the battery when welding on a vehicle?

MisterBill2

Joined Jan 23, 2018
18,167
Very informative! Thanks!
My "Tall Pointy Tower" has been the victim of a direct hit twice. And yes I am aware that there were note enough pointy objects on the ground to dissipate the charge. There are enough oak trees taller that even the top of the vertical on top of the tower, and they were rather wet with rain, and still they did not help enough to prevent the hit.
 

Halfpint786

Joined Feb 19, 2018
109
My "Tall Pointy Tower" has been the victim of a direct hit twice. And yes I am aware that there were note enough pointy objects on the ground to dissipate the charge. There are enough oak trees taller that even the top of the vertical on top of the tower, and they were rather wet with rain, and still they did not help enough to prevent the hit.
Unfortunately, as the ham guys trying to tune up tree trunks have found out, trees are very poor conductors. And rain (distilled by nature) is also very non-conductive. Its an insulator more than anything.
 

MisterBill2

Joined Jan 23, 2018
18,167
Unfortunately, as the ham guys trying to tune up tree trunks have found out, trees are very poor conductors. And rain (distilled by nature) is also very non-conductive. Its an insulator more than anything.
Given the quantity of industrial dust that settles on everything, in my area I would expect that the rain would wet the dust and be rather conductive. But maybe not. The challenge being how to get a lightning rod up higher than the tower, while not attracting unwelcome attention.
But really, a half dozen wet trees all higher than the tower and less than a hundred feet away should have some effect. Or maybe they all contributed to the accumulation of charge in my area.
The challenge being that it is difficult to hide a tall tower, no matter what color it is painted.
 

dcbingaman

Joined Jun 30, 2021
1,065
My "Tall Pointy Tower" has been the victim of a direct hit twice. And yes I am aware that there were note enough pointy objects on the ground to dissipate the charge. There are enough oak trees taller that even the top of the vertical on top of the tower, and they were rather wet with rain, and still they did not help enough to prevent the hit.
The theory in the video sounds nice (in theory at least). How you could ever test it, I don't know. I doubt we have a good understanding of lightning even in the 21st century, it is just not predictable.
 

Halfpint786

Joined Feb 19, 2018
109
I live in northern MN surrounded by water on a tall clay hill and my antenna is the tallest thing for a mile. But my antenna and ground plane are all at dc ground, my tv yagi with its couple dozen points is at DC ground, and the cabin has three lightning rods each with their own ground rod (but tied together across the roof). We have had some terrifying storms come through here and the closest strike I can ever recall was about 1/4 mile away in lower land. Maybe I am just lucky. Maybe all those pointy grounded things actually help.
 

MisterBill2

Joined Jan 23, 2018
18,167
May years back I worked on a farm for my uncle in the area north of Thief River Falls, so I am sort of familiar with it. As I recall most structures all had lightning protection systems if they were over ten feet tall. so evidently the need for them was well understood .
Each leg of my tower has a copper (not copper plated steel) 8-foot ground pipe connected by a short length of size "0" (much larger than #0) copper cable crimped into the end of the copper pipe. So most of the strike goes into the ground. But there is still enough to do quite a bit of damage.
No other structures within a mile seem to have any lightning protections at all, and most of the other tall trees have been removed by developers as they built bigger houses.
 

Reloadron

Joined Jan 15, 2015
7,501
So then you think welding something else in the garage with your car parked in it is going to fry the car? I have both a Tig welder with high frequency start, and a industrial type Mig welder with in 4 feet of a simple old boombox that's on while I weld, never any type of interference on the radio while welding. But did have a old bad florescent light that gave interference on the radio.

Welders made today have to pass federal standards as to radiated emissions. as to welding leads I've never routed the leads through anything when welding, so can't answer that one.
OK this is slightly off topic but humorous. Then came Bob. Bob was an old time calibration guy we had. Bob went back in the plant to when the calibration guys were referred to as "needle benders". Needle as in analog meters. Bob calibrated our welding machines and we had just about every welding machine you could imagine. Some really big systems. Many of the TIG machines used an RF start. One test or cal check was measuring the AVC (Arc Voltage Control) voltages. You load a scrap workpiece and using a DMM measure the arc voltage once the arc is struck. Bob had a habit of connecting the DMM to the weld head and work piece before the arc was struck. So along comes the RF burst and there goes another $1,000 HP DMM. The procedure called for the tech not to connect the DMM until after the arc was struck and the RF pulse was complete. :( My humble office was becoming a graveyard for very expensive recently deceased HP DMMs.

Rather than try to retrain Bob the solution was simple. Made a small box containing a choke. The choke went between the electrode and meter input. I forget the value of the choke but it duplicated the chokes used in many arc machines between weld head and their metering systems. Bob eventually retired and my life improved. :)

Shortbus, how about 10 years ago? :)

Ron
 

shortbus

Joined Sep 30, 2009
10,045
I gave up trying to make a Tig with HF start. I bought one instead. I have not looked back since doing it, this thing is both inexpensive and almost as good as any industrial machine I ever used, the only thing holding back from equalling those machines is the amperage. But most everything I weld is well within it's limits.

The price has dropped even more than I paid.
https://ahpwelds.com/products/alphatig-201xd?variant=39353828507830
 

Reloadron

Joined Jan 15, 2015
7,501
I gave up trying to make a Tig with HF start. I bought one instead. I have not looked back since doing it, this thing is both inexpensive and almost as good as any industrial machine I ever used, the only thing holding back from equalling those machines is the amperage. But most everything I weld is well within it's limits.

The price has dropped even more than I paid.
https://ahpwelds.com/products/alphatig-201xd?variant=39353828507830
Some things are just easier bought. :) "Sold Out"

Ron
 

Reloadron

Joined Jan 15, 2015
7,501
so how does the current of the welder kills the electronics if they dont have a path to finish the circuit?
There is a path for very high current flow, right across the arc. The arc created by the high current flow in turn produces a strong EMF (Electro Magnetic Field). Anything including humans and sensitive electronics can be exposed to that field. We have a path for current flow right across the arc and the arc produces a strong magnetic field which can be fatal to sensitive electronics. That's how it plays out. Now exactly how sensitive the electronics can be or how much shielding protects the sensitive electronics I can't tell you. The actual strength of the field measured in Volts/Meter will be a function of the Voltage and the Current creating and maintaining the arc. That's about how it all plays out.

Ron
 
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MisterBill2

Joined Jan 23, 2018
18,167
There is a path for very high current flow, right across the arc. The arc created by the high current flow in turn produces a strong DMF (Electro Magnetic Field). Anything including humans and sensitive electronics can be exposed to that field. We have a path for current flow right across the arc and the arc produces a strong magnetic field which can be fatal to sensitive electronics. That's how it plays out. Now exactly how sensitive the electronics can be or how much shielding protects the sensitive electronics I can't tell you. The actual strength of the field measured in Volts/Meter will be a function of the Voltage and the Current creating and maintaining the arc. That's about how it all plays out.

Ron
Sometimes I am given safety precautions relative to things that I am not familiar with. and sometimes warnings about hazards where I am not aware of the mechanism of harm from such a hazard. The fact is that just because the exact mechanism of the hazard is not clear to me does not mean that it does not exist. That has included electrically "hot" hardware that certainly should not have been hot, and high pressure leaks that should not have been leaking, and a gas charged accumulator that should not have burst when it did, and also an area where there was no oxygen, because of a gas leak.
My point being that not every hazard is clearly visible or easily known.
 

MaxHeadRoom

Joined Jul 18, 2013
28,617
so how does the current of the welder kills the electronics if they dont have a path to finish the circuit?
There is a path for very high current flow, right across the arc. That's about how it all plays out.
Also you cannot rely on the adage, 'Current always finds the path of least resistance' it also finds as many other paths as it can!. :oops:
 

Reloadron

Joined Jan 15, 2015
7,501
Sometimes I am given safety precautions relative to things that I am not familiar with. and sometimes warnings about hazards where I am not aware of the mechanism of harm from such a hazard. The fact is that just because the exact mechanism of the hazard is not clear to me does not mean that it does not exist. That has included electrically "hot" hardware that certainly should not have been hot, and high pressure leaks that should not have been leaking, and a gas charged accumulator that should not have burst when it did, and also an area where there was no oxygen, because of a gas leak.
My point being that not every hazard is clearly visible or easily known.
Well we have the visible hazards and then we have the invisible hazards, those we know and those we don't. Ever wonder why nobody robs a bag man for thew mob? Ever wonder why some people wear a dosimeter badge? :) I wonder about those things, especially during NE Ohio winters as cabin fever sets in. :) If my doctor tells me I need more sunshine why can't he just write a prescription so I can go to the Carribean and have Medicare pay for it or my supplement insurance?

Ron
 

piniiii

Joined Oct 30, 2019
20
so that leaves me with more doubts, like a million of them, like then what if 450 CCA are on ground and the starter motor positive cable? that wont generate a electro magnetic field like the one you mencioned and probably burn things up? not trying to discuss with you, just want to order the things on my mind
 

dcbingaman

Joined Jun 30, 2021
1,065
Sometimes I am given safety precautions relative to things that I am not familiar with. and sometimes warnings about hazards where I am not aware of the mechanism of harm from such a hazard. The fact is that just because the exact mechanism of the hazard is not clear to me does not mean that it does not exist. That has included electrically "hot" hardware that certainly should not have been hot, and high pressure leaks that should not have been leaking, and a gas charged accumulator that should not have burst when it did, and also an area where there was no oxygen, because of a gas leak.
My point being that not every hazard is clearly visible or easily known.
True, there is a lot of things we are exposed to in our modern society that may or may not have harmful effects. High voltage lines, cell phones against the side of our heads next to our brain, etc. I would not be surprised if high EM fields might have detrimental effects on biological systems, whether those fields be static or dynamic (i.e. EM waves). Consider the nerve cells that go from the brain, down the spinal cord. Not to many people are aware of the fact that these cells are the longest in the human body as the axon of the cell is many feet long; Yes very thin but extremely long. Being the wavelength of the field in compatible with these cell lengths, I would not be surprised if such fields interfere to some degree with proper functioning of the nervous system and who knows what the long term effects are.
 
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