Originally Posted by ClydeCrashKop

I will have to study that. Maybe I can put the current resistor on the main supply. It would only see pulsating DC.

Haha, oh yeah. It never occured to me from staring at the diagram that the power would only enter and exit through two terminals of the battery in a single direction...hehe.

Originally Posted by ClydeCrashKop

Is that current sensing resistor similar to a remote ammeter that uses a shunt on the mains?
You have no idea how much I have learned while researching all of the help you guys have given me today. I found a lot of good info on all of the above subjects at http://www.irf.com/technical-info/appnotes.htm including this one as a future project: AN-1045: AC TIG Welding: Output Inverter Design Basics PDF
Thanks a lot

I think so (I am soley drawing on the definitions you are using, I believe I have seen others refer to a current sense resistor as a shunt before.). It's just a very low resistance resistor so that a small voltage drop forms across it depending on the current flowing through it. You can measure this voltage to figure out the current flowing.