@GetLeft , I'm always surprised at the variety of techniques people are exploring with the Nomad, thanks so much for sharing!
I'd have to agree that from 4.2v to 3.7v on the low heater is a pretty sweet spot.
Question, have you tried cleaning around the hole where the heater module connects to the bronze bottom plate? Also clean the outside of the heater module shell, where it touches the bronze around the rim.
A pencil eraser can be used for cleaning the bronze, and the abrasive pads, fine sandpaper, or pencil eraser can be used to clean the heater module shell.
The patina on the bronze will have a pretty big effect on amp draw. It may appear visually clean, but if the patina is too thick it will definitely make the unit run cooler with both heaters.
The pencil eraser gently removes the patina down to shiny bright metal without leaving scratches, and it nicely blends the bright clean area into the cool patina on the rest of the bottom plate.
It appears as though regular use of the Nomad keeps the contact areas clean via electrical cleaning. I've read a few papers that would suggest the same thing happens with electro-mechanical relays, so there is something to it I think.
From what I've read, when the patina is somewhat thin, the electricity is able to punch through that layer and effectively clean the patina away. With regular use, maybe daily or every couple days, the electrical contacts should remain clean almost indefinitely. (I'm on a every 6 month - 1 year cleaning cycle).
But I've suspected that if the Nomad is left on a shelf without use for a month, the patina layer will be allowed to thicken to the point where the current can't punch through that layer very well, resulting in resistance, lower amp draw, cooler over-all experience.
This is most likely to happen at the connection point between the heater module and the bronze bottom plate.
The connector bridge connections are sliding contacts so they clean themselves, no need to ever clean these. And the button connection should be shielded from air by the button lube, so patina growth is much much slower here.
So, what I'm saying is that a Nomad a day keeps the cleaning sponge away, haha.