I hope you can do it,
.
I'm confused though. You are trying to connect a DC current to your soldering iron? You would need to wire the 75W inverter in between the two wouldn't you?
Maybe these links will help?
Super easy DIY rechargable battery and
Portable Powerbox
I wonder if a UPS would work? I ran a CFL on one our last power outage.
Yes, for some reason, I think a poor connection in my cig lighter some where would not glow the rod with the
inverter, it would get warm but not glow unless the car was running.. Today however, I jumpered the inverter directly to my car battery and it worked awesome! So it should work fine if i get enough amps to it, that or i was doing something wrong with the dewalt battery? I think i can get this going now though with enough AW 18650's. Pretty sure the iron only draws less than 0.6 amp so still a bit confused.
Edit: I think the inverter draws a few amps just by itself to produce that 75 watts and my vvps will stop at 2A so maybe that is causing the LED to pulse.
I have 4) 18650's in a 4S1P pack config now and if I hook that to the DC-DC vvps, set to voltage to 13v on the vvps, the LED on the iron will pulse rapidly but not get real hot.
If hook the 4S1P pack straight to the inverter @16v, the LED will just flashes once on contact.
I will try a multi packs of 4S1P in parallel and see if that works. again, i dunno..