New coil, with new wire, no flux would be needed.

-Hans

Yep, the wiring you're soldering to the lug. No real benefit to adding flux, as the solder core already contains it.

That's the nice thing about a new machine.....the wiring in the game isn't 30 years old and oxidized by being soaked with beer and god knows what else.

-Hans

For leaded solder, typically in the range of 650F is what you'll use for iron temperature.

I'm not aware of any good cordless soldering irons, pretty much any soldering iron worth using (with temp control and good handles/tips) is going to be corded with an external power supply.

-Hans