Inverter Flux-core Welder off of Battery

[baymoe]

I've been tinkering with this welder with some mild steel and was constantly tripping the breaker in the garage. It's a detached garage and running a new line is currently not a solution we'd want to tackle. I came across units like Karnage (Karnage Welder) that produces cordless flux-core welders for the off-roading community and wish to modify my current welder to run on a dc power supply and hope that anyone with a more electrical knowledge can assist with this build. I have experience building lithium battery packs and is looking to modify this welder to accept a dc battery pack to weld. I have access to battery cells of all types (lithium phosphate and nmc) that can handle the required power draw.

Can I simply connect 12v off line 2 and 4? Any help or advice appreciated.

 

[marty]

Don't know answer to your question. Better PDF drawing might help others to find lines 2 and 4. Having trouble viewing JPG image. Numbers are too small.

Link to:

Operator’s Manual
Lincoln Electric
WELD-PAK 90i FC

https://pdf.lowes.com/productdocuments/2a9b0aca-86a1-45c7-b5a3-3fbf051ee42c/63524545.pdf

Page 14 or 18 depending on how ya count pages. 63524545_18rotate.pdf

Extract page from pdf file with Adobe Acrobat Pro DC. DC as in software not electricity.

Rotate page from portrait to landscape. That's better. Electricity always flows from left to right.

 

[baymoe]

 

[baymoe]

Thanks Marty

 

[marty]

Close up of rectifier. Is that where you finding lines 2 and 4? I would say "try it". Before you modify. Measure voltage at lines 2 and 4 with machine on.

 

[marty]

Use a fuse.

 

[A-DamW]

Can I simply connect 12v off line 2 and 4? Any help or advice appreciated.

First off, I think you will want more than 12 volts to get sufficient current for welding, most rat-rig welders use 2-3 lead acid batteries in series{24-36 volts)
The schematic you supplied looks somewhat incomplete, it shows one AC line center tap connected to what appears to be a mosfet half bridge, and the other AC line connected to a full bridge rectifier?
I am guessing both AC lines actually go to the full bridge rectifier, it doesn't make sense that it would be in a simple one-way diode configuration, only one half of the AC waveform would be used.
I would echo what marty said above, bust out the multimeter, and (carefully) probe around.

 

[marty]

(carefully)

Good advise. Good way to get electrocuted. One hand grounded. Other hand poking around at 120V. That way electricity runs through your heart.

Unplug machine when poking around. Alligator clip test leads are one of my favorite tools.