Arc welding leads off my 24Volt CUCV?

[suprdave737]

Useage would be out in the woods building my shop, no power out there yet and dont have a big enough generator to run my mig or stick out there.

Ive got a 85 chevy K30 6.2 diesel, CUCV military truck with 2 batterys and 24 volt starter setup and dual alternators. Since it has 24 Volts available - the 2 batteries are in series already - Can I weld with this thing right off the batteries without blowing them or the alternators up?

DC electrode negative 24 Volt so the ground lead off one battery positive terminal and the stick welder electrode holder connected to the second battery negative?

Does it need to be not running so it doesnt fry the alternators, or weld with it running?

Thanks, Dave

[Nowhere]

If you weld with the truck on, the alternators will be under a great deal of load. As the voltage drops when you weld, the alternators will try to bring it back up. If you were to weld with the truck off, then run the truck for charging, the alternators would only put out as much as the batteries can take (while charging).

If you were to weld with the truck idling, the speed of the alternator would govern the output amperage (ie. while you are at idle, the alternators could only put out 50 ~ 75 amps vs. @ say 2500+ rpm they would max out (maybe 100 ~ 125 amps each?)).

Dunno.

[suprdave737]

I see where you are getting at but since the leads are connected direct to the batteries its a direct short its going to weld at whatever amperage it takes to melt the electrode- example 3/32 6011 will melt at a lower amperage than 5/32 rod. On a long weld- voltage will start to drop I guess.

Im thinking that the actual welds will only be a few seconds at a time and it will have a while to charge between welds.

I may just have to give it a try and see what happens, its a non licensed work truck on my land only.

[roverjohn]

I would buy/make a low resistance inductor and place it in series with one of your welding leads. It will improve arc starting. I wouldn't worry about the alternator. As long as you keep engine rpm low it will not see much load. Your batteries will overheat before your alt will.

Google "DIY battery welders" and you can see how people build their inductors. It's pretty simple.

[Wicked_S10]

I would think that the back EMF when you break the arc will fry shit in the electrical system if the batteries are left connected to the vehicle.

It may work and be fine, just my first thought and gut instinct is that it will toast shit.

[BumpyDodge]

24v is too low open circuit voltage to really stick weld with, 3 batteries in series works better (36ocv) but it's still difficult to start the arc.

Readywelder will CV MIG weld no prob with 24v. If you cucv has a slave cable receptacle on it somewhere (military jumper cables = "slave cables") You can make it "plug and play" hookup.

[suprdave737]

Thanks, Maybe I will give it a try with a small diameter electrode rod with the 24 volts off the truck. Im hoping to use it off 24 volts so I dont have to mess with anything weird charging 3 batterys at 36 volts or having to disconnect them from each other to charge or ect.

And yes the truck does have plug in connectors in the grill for battery cables.

[sewerzuk]

I welded with 24V off of one of my rigs for a few years...I always did it with the engine running and never had any real problems..did burn up one cheap GM 1-wire alternator but the powermaster I replaced it with worked just fine until the day I sold it. I did notice a few things though:

1. Stick welding is usually done constant current (voltage varies as necessary to maintain a constant amperage). What you are doing is a constant voltage setup. When you stick weld with CV, it is quite a bit different than welding CC. I have had lots of experience welding with an AC CC welder, but I had a difficult time making my welds look good when using my Samurai as the power supply. I also tried CV stick welding with an old Linde welding power supply, and never could get it to stick weld well. The one advantage of using batteries...they can provide 800 amps or more (compared to 200-300 A for conventional power supplies)...that means sticking the rod to your workpiece is VERY rare.

2. I ended up buying a Ready Welder. CV is what is normally used for MIG and flux core welding, so your 24V setup is perfect for this. I was able to make some pretty nice welds with this while connected to the vehicle. With flux core, 1/4" and 5/16" were no problem (using shielding gas will reduce this capacity a little). I currently use it as a spoolgun for MIG welding aluminum on my millermatic 251...so it is something you can use for future upgrades.

[suprdave737]

thanks for the info sewerzuk dude