I have a Century mig that runs off batteries. It uses cored wire or I have a solenoid that you can use standard wire and gas. If anyone is interested I would like to sell it. I have moved on to big money welders
Cored wire is good in the wind!
Bringing up a post from the past- I've got a chance to buy a ReadyWeld II used (new in box) and it certainly looks like it would work for me. I've been thinking about a mig welder that can do steel and aluminum, but have heard I need a spool gun to do the aluminum, as the aluminum wire tends to bunch up in the line.
I have a 48VDC UPS in the garage that can supply 270 AH, plus three spare 12V batteries I can hook up.
Any problems with only being able to adjust the voltage in multiples of 12? Is that too course for fine work? I'll need to do sheet steel as much as heavier stuff.