Looks like it has capped out at about 1.95 volts now. Seems directly tied to how hot I have heated the heater. 1.7volts at 180C and 1.95@210C Edit: indeed it is actually tied to how much power is needed by the heater. I turned it off, the power drops, if it needs to hold a certain temp it stays at 1.95 when fully charged, and when it is heating it can get all the way to about 2 volts. And as I said, this is measurable from anywhere there is an electrical connection to a component, but the voltage is directly tied to the power the heater is receiving.