Car Battery Powered MIG Welder

[Rabbit]

Hi just thought I would let you know I have managed to adapt my sip 100 amp mig to run on battery power using 3 car batteries - reason being to be able to weld where there is no mains electricity. This was done as follows:

one car battery connected to 800w 240v inverter with welder plugged into it. Welder set to lowest current range. This provides the power to the wire feed motor.

The other two car batteries are connected in series to make 24v. The negative of this 24v is connected to the earth lead. The positive is connected to the terminal in the welder where the heavy welding current cable goes out and down to the torch.

The torch is thus premanent +24v.

turn the inverter and welder on, try the wire feed.

go weld!

 

[shenion]

Connect the battery on the other side of the reactor choke or you will get lots of spatter and little penetration.

 

[chris y]

Brilliant.

Any chance of a couple of pics of the setup and the welds you can achieve.

I have a garage away from home with no power, we have a small generator that could be used for wire feed and what you say for welding current.

How much welding can you do on a battery charge?

 

[chris y]

Connect the battery on the other side of the reactor choke or you will get lots of spatter and little penetration.

Would you be able to elaborate on this please, what is the reactor choke purpose, how does it work and how to identify it.

Thanks in anticipation.

 

[shenion]

The reactor will be between the bridge rectifier and either the torch or work lead. Will be a large, transformer-looking thing with 2 leads.



Picture taken from another thread. Reactor shown with black box around it.

It is needed for short-arc transfer (dip-arc) to smooth out the current.

 

[chris y]

Thanks Shenion.

That makes sense.

 

[Rabbit]

Like shenion says, you do need to connect the - of the 24v before the choke. The purpose of the choke is that it slows a sudden surge of electricity, smooths the current flow. It is a heavy inductor, basically a heavy coil of wire.

Shenion's pic is pretty much identical to the insides of my welder.

You can see an m6 silver nut and bolt at the top left of the black box in his pic. This bolt is undone and the wire on the choke is bolted onto the - of the 24v

The other wires that were on that bolt are left not connected to anything.

In the top middle of his pic you can see an heavy black cable bolted on an aluminium plate. This cable is unbolted from the plate and bolted onto the + of the 24v.

I have welded 3mm thick steel with it ok. Not sure how many welds you would get out of a battery, depends on the battery capacity. Be good with some bus or tractor batteries.

Useful for the odd weld here and there in no power locations

 

[chris y]

Thanks for the info, I hope to try this sometime.

 

[tom-madbiker]

i have arc welded with three car batteries before it works quite well seem to remember using 2.5mm rods got about 1m of weld to the charge lovely and smooth tho but difficult to keep the arc steady needs to be fairly short cos of the low voltage

 

[rich r]

I've tried arc welding directly from three car batteries and a pair of jump leads too - just to see if it worked. And actually it worked a lot better than I expected it to.

Connect three 12V batteries in series with a two jump leads to give you 36V - ie just high enough OCV for 6013 rods. Then simply use one of the other jump leads on the negative terminal for your earth connection, and the other from the positive to clamp a 2.5mm 6013 rod. It helps if these jump leads have chunky metal croc clips rather than flimsy plastic ones which will melt!

Took a few goes to get it to strike, but once the rod was hot I could run a good weld. As Tom said, you have to move very smoothly and slowly and keep the arc really short - dragging is the way to go - or it'll stop. I suppose given I'm used to an AC buzzbox, it's my first experience of DC MMA

I can see that people can effect perfectly good repairs on vehicles in the middle of the desert with this technique.

 

[dannyp]

tryed arc welding useing a forklift battery before. that was intresting to say the least.

48 volts and no shrtage of current