Welding with car batteries.

[blksmok]

Who's done it? I've seen it talked about in offroad/4X4 magazines to get people back on the trail when you are in the middle of nowhere, but I don't know anyone who's actually done it, or knows what it takes.

My questions are, how many batteries do you need? I'm assuming "X" amount of amps, so it depends on the batteries you have and I'm assuming you connect them in parallel, and then use a jumper cable with a welding stick in the positive clip and the negative connected to whatever you are trying to weld?

What am I missing?

[Crazy_Steve]

Theres a discussion, pic, and helpful link here: http://www.survivalistboards.com/showthread.php?t=6518

[Vrabel]

would not suggest it. every time you strike an arc you create a dead short. creating a chancing a battery to explode. when I was a kid,some knuckle head used a battery charger. burned down his garage, killing his 4yr old son trapped in the blaze.

[Vrabel]

i did not put cartoon in! and I too thinks itsw very GAY!

[BackNBlackTJ]

I've done it a couple of times... while wheelin'

works best with 2 batteries and 2 sets of jumper cables... 2 batteries can weld 1/4" plate, main problem is that there is NO heat control so you can burn through really easy.

I actually have a set of cables I built with battery clamps and ground/stringer ends, I carry 6011 .120 rod (decent universal rod) in a watertight PVC cannister when I go out.

http://inlinethumb59.webshots.com/7226/2560495880036728711S500x500Q85.jpg

[Mike]

That's right, two or more batteries in series. Just don't let the voltage go too low and limit the duty cycle unless you have huge batteries with a huge ah rating.

I was looking through a northern tool wish book and noticed one a while back.

I've used a huge forklift 36v battery before. Just tried it though, no weld quality tests. After all, it's just dc voltage us DC rods.

):h

Really though, limit the size of the electrode. Use the smallest you can get by with. Oh and use really long cables unless battery acid it cool.

I'd still wait for an expert at any rate to chime in....

[blksmok]

I thought when welding, the current did the welding, not the voltage... If so, you would want to hook the batteries in Parallel as that would allow you to obtain higher Ah.

I found a good picture to show the value of series vs. parallel connections of batteries.

Series:
http://www.batteryuniversity.com/images/partone-24a.jpg

Parallel:
http://www.batteryuniversity.com/images/partone-24c.jpg

[Mike]

I think 6 or 12 volt would work but lots of amperage and hard to keep an arc. Lots of heat as voltage drops. The resistance, ie work piece, cabling and rod , if cabling is not sufficient, stays constant. If voltage drops, electrode size should also drop.

Voltage is pressure right.

Depending on the process but constant current supplies and constant voltage supplies.

Can have voltage without current but no current without voltage. Raise the voltage, lower the current.

With batteries only, you have to regulate the current with the electrode/cabling. The electrode drops voltage across it and changes as it's consumed.

Time to go pick on some batteries.

[Mike]

I thought when welding, the current did the welding, not the voltage... If so, you would want to hook the batteries in Parallel as that would allow you to obtain higher Ah.

I found a good picture to show the value of series vs. parallel connections of batteries.

Series:
http://www.batteryuniversity.com/images/partone-24a.jpg

Parallel:
http://www.batteryuniversity.com/images/partone-24c.jpg


Same wattage both ways. Just heavier cabling required as voltage lowers in the same wattage scheme.

Try using a 6011 rod on a dc machine or even these batteries with electrode positive and then electrode negative. One way is harder to keep an arc than the other. Or, one returns current through the rod the other returns current through the work piece. Or, one heats the work piece, the other heats the rod.

[BackNBlackTJ]

Running the system electrode negative will turn your rod into a bright red mess, all the flux will blacken and flake off. I've always run it electrode positive and it only burns at the arc. Oh and another thing is the batteries work "better" if they are a matched set ie: both 800cca, etc. Not saying the system doesn't work if they are not just it works better.