anti-spike devices

[norsa]

Have a modern car coming to have a repair at the weekend and it will require my stud welder. When i ran my business pre 2000, i had a sealey anti spike affair that clipped to the battery posts, never had a problem with spiking but wondered, in the interim whether its an issue on more modern cars. Have this nightmare where you disconnect a battery on a modern car then need to hook it up to a P.C to re-code e.t.c
Nick

 

[DrNik]

nope no problem at all, as long as you dont put the earth on the battery earth and the stud welder on the positive you will be fine, its only if you introduce a voltage into the cars wiring, just keep the earth as close to the area your working on all will be fine, oh and switch everything off

 

[norsa]

Thanks for that. This will also work presumably if worst came to worst and I have to mig a patch in?

 

[DrNik]

yes exactly the same, the current will pass through the passage of least resistance, so if you were welding a plate that held the earth on the battery there is the chance it could go through the battery and along the wiring, or if you welded through a wire (that would be really bad), but for what your doing you will be ok

 

[norsa]

thankyou doctor.

 

[steveo3002]

yeah used those at the main dealers ..no problems at all

 

[DrNik]

how about one of them bomb detectors changed into an anti-spiking fool, i mean tool

 

[norsa]

the ones that have nothing inside them?

 

[ajlelectronics]

It will be every bit as effective.

 

[DrNik]

i reckon i could sell them to people who are scared to weld cars whist the battery is connected

 

[Marc.]

Have this nightmare where you disconnect a battery on a modern car then need to hook it up to a P.C to re-code e.t.c
Nick

I have been there just a few weeks ago! Did a clutch change on an s reg saxo and after reconnecting battery seemed fine.. then after about 10 seconds dropped down to running on only three cylinders, and then two... once plugged into launch it turned out that when i disconnected the battery the ecu had somehow lost all of its configuration settings for the car and had gone into factory default.. Spent about three hours coding everything back in including type of alternator, gearbox etc etc. Bloody modern cars! I prefer the classic or american vehicles still to the modern stuff!

Marc

 

[tiger99]

I am an electronics design engineer with considerable experience of protecting systems from spikes and I can tell you that any device connected across the battery is not addressing the problem at all, as far as welding-induced spikes is concerned. The battery itself has thousands of times more capacity to absorb spike energy than one of those things. Basically they are snake oil.

The risk of damage to your car's systems during welding can only be relieved by pulling out a few plugs, alternator, engine management computer, stereo etc, i.e. uncouple anything that contains solid state electronics from the wiring loom. The grounds can remain connected.

For MIG welding I would not bother to do any of that, as long as I was not welding anywhere near an earth connection for any of the electronics, and had the welder earth connected very close to the welding area. But for TIG, with HF start, I would definitely be disconnecting ALL the electronics.

 

[DrNik]

I am an electronics design engineer with considerable experience of protecting systems from spikes and I can tell you that any device connected across the battery is not addressing the problem at all, as far as welding-induced spikes is concerned. The battery itself has thousands of times more capacity to absorb spike energy than one of those things. Basically they are snake oil.

The risk of damage to your car's systems during welding can only be relieved by pulling out a few plugs, alternator, engine management computer, stereo etc, i.e. uncouple anything that contains solid state electronics from the wiring loom. The grounds can remain connected.

For MIG welding I would not bother to do any of that, as long as I was not welding anywhere near an earth connection for any of the electronics, and had the welder earth connected very close to the welding area. But for TIG, with HF start, I would definitely be disconnecting ALL the electronics.

Yay i agree, at last someone with knowledge,ive said this all along but people get scared thinking its a different kind of electricity or voodoo
as long as you dont weld through a wire nothing bad will happen to the car

 

[Welderpaul]

I MIG welded a big drawbar on a new fancy wagon last week, lots of electronics on it, had the earth right next to where I was welding; no problems with it. (Thankfully)

It was a 30mm thick plate that I welded on so was not shy on the volts. I got her to start the wagon up after I tacked it on...just to make sure....