Welder on battery power?

[BioHazard]

Kinda off topic, but I thought this would be a great place to ask. I have a cheap old harbor freight wire feed welder that I haven't used in several years. The stupid thing has a regular 15A 120v cord, yet, says right on the front it takes 22A input. Where am I supposed to plug that in? 

Anyway, I was wondering if it would be possible to replace the transformer part with a pair of deep cycle batteries? It says "Max 31 OCV, 19.5v @ 60A, and 22v @ 90A. The motor that feeds the wire uses the welding outputs for power, and only has a 10% duty cycle.

Can I get rid of that worthless transformer, and replace it with a 24v battery pack, and a slow charger? I'm interested in building a gas powered welder, but not something as huge or powerfull as a commercial unit. That way I would only need 10 amps to charge for 100 amps of welding, with the same 10% duty cycle. How could I control the welding amperage though?

[mobile_bob]

i used to have a small suitcase welder made by century that was powered by two agm 12volt internal batteries
it was connected in series for 24volts dc, and used a small wallwart transformer/charger to recharge with.

it used flux cored wire

it had no amperage setting, but rather the heat was done via the wire speed control, kind of odd but it worked very well

i wish i still had it, because i wanted to do just as you are thinking of doing and use an engine powered alternator to recharge with.

thanks for letting me know about the harbor freight welder using the welding output for powering the wirefeed motor, i think what you want to do is feasible and will probably work, so long as you accept the limitation of having to control heat with the wire feed speed control which precludes the unit from welding very light gauge sheet metal.  of course flux cored migs aren't great on gauge metal anyway in my experience.

bob g

ps. after posting it occurred to me that if you run a large enough alternator, it might be that you could use a reostat control of the field to get some control over the amperage of the mig, that is unless you use fairly large batteries then perhaps the control might be limited to between 60% and full power?

[WGB]

Bio, I had the same model as Bob had.
I had the optonal gas regulator and liner, so I could use standard gas and wire.
It was not the best, little of topic but maybe I will help you.

[BioHazard]

MIG welders have two controls - voltage and wire speed. There is no amperage control, it is always directly related to wire speed (and wire thickness). MIG is a constant voltage process, stick is a constant current process where you adjust current but not voltage.

Hmmm...the welder has a setting for 60 or 90 amps though, along with the speed control. (can't use the 90A setting with a normal outlet though) The ground cable is only about 10ga and gets extremely hot, so that's probably limiting current too. Doesn't matter too much, I don't weld thin stuff anyway, I just make holes.

[Ronmar]

Yep, the control is for two different voltage settings, or in the case of the plug in wire feed welder, different secondary windings on the transformer.  As Jens mentioned, weld current is more a factor of wire gauge and wire feed speed.  A change in voltage can give you a little more flexibility to the overall wattage delivered...

It will probably weld great with DC from batteries.  My lincoln weld pac is the same way, the rectified output from the transformer that feeds the process also powers the drive motor.  There is an over temp sensor buried inside the transformer, and with all the use I have put it thru over the years, I have overheated it quite a few times.  When the transformer finally kicks, I will replace it with a bank of 3 batteries, as mine runs in the mid 30's for voltage...

I think northern tool still sells the handi mig units.  if I recall correctly, two fully charged car batteries are good for about 45 minutes of weld time...   

[veggie]

Many of those smaller units work reasonably well on 120vac. using 3/32 rod.
Why not plug it into the 120v outlet on your generator an see how it works.
Might save you a lot of fiddling around with batteries and wiring.

veggie

[LowGear]

Why not plug it into the 120v outlet on your generator an see how it works.

When the price is 10 minutes fiddling around - Why not?

Casey

[BioHazard]

Many of those smaller units work reasonably well on 120vac. using 3/32 rod.
Why not plug it into the 120v outlet on your generator an see how it works.
Might save you a lot of fiddling around with batteries and wiring.

Actually I already have several 30A 120v twistlock outlets around the shop and an adapter to plug in a regular 15 amp plug...but I'm more interested in making it portable without a generator. Obviously it was never a top quality welder to begin with, I'm looking for a big old 240v arc welder for the shop.

[Ronmar]

I don't think a .035 flux core wire is going to work real well being fed 120VAC.  MIG is a DC weld process, the more pure the DC, the better...

[mobile_bob]

i don't know what flux cored wire does on 120ac, but i do know what a piece of E6 .035 mig wire will do wrapped around
the plug of a boom box when it is plugged into the wall socket!

shall i say, BOOM!

think blinding flash, big BABOOM and a dude with brown shorts!



bob g

ps. yes they learned to turn the volume down when i needed to work in the plant from then on.

[Tom Reed]

I don't think a .035 flux core wire is going to work real well being fed 120VAC.  MIG is a DC weld process, the more pure the DC, the better...

I've got a little cheapo Century 120vac welder. It was given to me  because the guy that had it said it would not weld right . It turns out he was using solid core wire with no shielding gas. I've used it successfully for some projects that are well beyond its rated capacity such as welding up the Listeroid frame and welding a new front bucket on the front of the JD1010. It even works ok on roid power too, even better when the governor is turned up a bit.  The duty cycle does suck though, when turned up high it will weld about 1" at a crack.

[LowGear]

I had one of those Century units as well.  I smoked it up learning what "duty cycle" really means.  It was a nice unit.

Casey