Welders

[Zoobi]

The first time I welded with two batteries and jumper cables, they melted through one of the battery posts. The cables were not as good as the ones in the video and we used a jumper cable between the batteries. The "kit" I put together later, mounted to the batteries. It worked so much better that way.

[mkjeepers]

I saw this on welding with 2 car batteries.

http://youtu.be/PV5oLPLUzrM

[mkjeepers]

More discussion on welding on a vehicle.

http://www.aws.org/cgi-bin/mwf/topic...?pid=27481;hl=

[HookandLadder]

Yep, my buddy knows some one who used to.....See here, the factory says.....

The problem is the possible damage to the vehicle computers. Newer engine computers (pcm, ecm...) are very well protected, older ones were not. Body, gauge, air bag computers are easier to fry from voltage spikes.

Is it possible to "detonate" a battery while welding on a car? Absolutely but, you have a better chance detonating the batteries your using to weld with. Batteries produce hydrogen, add poor connections, high current draw and there you have it. When I use to use batteries for my Jeep welder I threw a floor mat on top of them. Any one who has witnessed a battery explode in a car will be cautious. My count is three, each one was while starting the engine (high current draw). 30 years in a shop, not too bad of odds there.

Back to the computer issues. Years ago I went away from battery welding and went to alternator welding. For me it was easier. If the ready welders were cheaper I would have one plugged into my alternator. On my 1980 Jeep I would weld on itself without any worry about spiking the distributor module or the radio. Remember the whole "electricity follows the path of least resistance" theory? Electricity has to go back to its source. Its much happier flowing between the electrode and clamp then say taking the longer harder way through that pesky engine controller. But the lawyers will ask "IS IT POSSIBLE" to burn out something? Sure, if you hook one end to the body, try to weld on the frame and the only path is through the electronics. People try to bring up voltage spikes like their something magical. They know how much damage can be done and that's where it stops. No one seems to remember that big voltage spike happening when their coil fires or the spike from the injectors...

I just say be aware of the potential problems, spikes can burn out computers and batteries can explode. The last thing anyone wants is being stranded covered with battery acid or not being able to start the vehicle because of a computer issue.


Scott

Well put!

[Zoobi]

One hard-to-kill totally false rumor about welding on vehicles is that the battery needs to be disconnected. Electrically speaking, there is no benefit to doing so. In fact, the battery isn't harmed by welding on a vehicle when it is connected and actually, having the battery in the circuit could theoretically filter (a battery also acts as a huge filter capacitor) out any spikes, though properly attaching the grounding clip close to the welding site makes any electrical spikes very unlikely. It truly is a false rumor the battery needs to be connected. That it does gets passed on like the gospel but it's of no benefit and simply isn't needed. Not to mention disco'ing the battery only disconnects the battery from the electrical system, everything else remains connected... like the far more sensitive components including the engine computer and alternator.

All this despite what someone's friend's cousin who is an "expert welder" said, since if you think about it, few welders know anything about electrical/electronic circuits beyond how to create a short circuit and melt metal.

Some interesting discussions on the subject

http://search.yahoo.com/r/_ylt=A0oGd...amage-cars-ECU

Yep, my buddy knows some one who used to.....See here, the factory says.....

The problem is the possible damage to the vehicle computers. Newer engine computers (pcm, ecm...) are very well protected, older ones were not. Body, gauge, air bag computers are easier to fry from voltage spikes.

Is it possible to "detonate" a battery while welding on a car? Absolutely but, you have a better chance detonating the batteries your using to weld with. Batteries produce hydrogen, add poor connections, high current draw and there you have it. When I use to use batteries for my Jeep welder I threw a floor mat on top of them. Any one who has witnessed a battery explode in a car will be cautious. My count is three, each one was while starting the engine (high current draw). 30 years in a shop, not too bad of odds there.

Back to the computer issues. Years ago I went away from battery welding and went to alternator welding. For me it was easier. If the ready welders were cheaper I would have one plugged into my alternator. On my 1980 Jeep I would weld on itself without any worry about spiking the distributor module or the radio. Remember the whole "electricity follows the path of least resistance" theory? Electricity has to go back to its source. Its much happier flowing between the electrode and clamp then say taking the longer harder way through that pesky engine controller. But the lawyers will ask "IS IT POSSIBLE" to burn out something? Sure, if you hook one end to the body, try to weld on the frame and the only path is through the electronics. People try to bring up voltage spikes like their something magical. They know how much damage can be done and that's where it stops. No one seems to remember that big voltage spike happening when their coil fires or the spike from the injectors...

I just say be aware of the potential problems, spikes can burn out computers and batteries can explode. The last thing anyone wants is being stranded covered with battery acid or not being able to start the vehicle because of a computer issue.


Scott

[inVERt'D]

Some interesting discussions on the subject

http://search.yahoo.com/r/_ylt=A0oGd...amage-cars-ECU

That was interesting, thanks! The comments regarding electromagnetic fields and inductance were definitely food for thought. I've noticed EMF at times while TIG--can make the filler rod get pulled to the work piece.

[mkjeepers]

Some interesting discussions on the subject

http://search.yahoo.com/r/_ylt=A0oGd...amage-cars-ECU

[inVERt'D]

Most of you guys respect Blaine's opinion on many things, ask him to see what he says on the subject. I know his feelings are the same as mine.

In that case, end of discussion!

[aw12345]

Blaine has a opinion about everything. Thing is, opinions are like @ssholes most all of them stink

[Jerry Bransford]

Most of you guys respect Blaine's opinion on many things, ask him to see what he says on the subject. I know his feelings are the same as mine.

[RAT]

Oh come on now, Kurt, how are we supposed to solve the great problems of our time if we can't hash them out a little?

^^ a bowl full might just help

[inVERt'D]

Oh come on now, Kurt, how are we supposed to solve the great problems of our time if we can't hash them out a little?

[RAT]

All this over kill. Just be safe and disconnect that damn battery! Or not. WTH

[inVERt'D]

One hard-to-kill totally false rumor about welding on vehicles is that the battery needs to be disconnected. Electrically speaking, there is no benefit to doing so. In fact, the battery isn't harmed by welding on a vehicle when it is connected and actually, having the battery in the circuit could theoretically filter (a battery also acts as a huge filter capacitor) out any spikes, though properly attaching the grounding clip close to the welding site makes any electrical spikes very unlikely. It truly is a false rumor the battery needs to be connected. That it does gets passed on like the gospel but it's of no benefit and simply isn't needed. Not to mention disco'ing the battery only disconnects the battery from the electrical system, everything else remains connected... like the far more sensitive components including the engine computer and alternator.

All this despite what someone's friend's cousin who is an "expert welder" said, since if you think about it, few welders know anything about electrical/electronic circuits beyond how to create a short circuit and melt metal.

Yeah, it's one of those rumors that has been perpetuated by endless anecdotes about drained, split, or blown-up batteries, blown alternator diodes and regulators and other problem. As if that weren't bad enough, it continues to be repeated by authoritative automotive publications.

I appreciate your thoughts, and probably what you say about the battery acting as a filter capacitor has some merit, but I think you've gone too far in being dismissive of the other school of thought.

Ready welder perpetuates the myth in its owner's manual (see FAQ #5):
http://www.pirate4x4.com/tech/billav...lineManual.pdf

Here's a random example:
http://www.i-car.com/pdf/upcr/procedures/ro/ro01s.pdf

Goodall Antizap (also sold by Snap-On, MAC, etc., etc.):
http://www.goodallmfg.com/antizap-surge-protection/

Since you like theory (as do I) here's an interesting theory on the subject from Wikipedia's GTAW (TIG) article:

http://en.wikipedia.org/wiki/Gas_tungsten_arc_welding
To strike the welding arc, a high frequency generator (similar to a Tesla coil) provides an electric spark; this spark is a conductive path for the welding current through the shielding gas and allows the arc to be initiated while the electrode and the workpiece are separated, typically about 1.5–3 mm (0.06–0.12 in) apart. This high voltage, high frequency burst can be damaging to some vehicle electrical systems and electronics, because induced voltages on vehicle wiring can also cause small conductive sparks in the vehicle wiring or within semiconductor packaging. Vehicle 12V power may conduct across these ionized paths, driven by the high-current 12V vehicle battery. These currents can be sufficiently destructive as to disable the vehicle; thus the warning to disconnect the vehicle battery power from both +12 and ground before using welding equipment on vehicles.

[curtis]

I was talking about the batteries you use for welding.