I was running a few more tests the other night after fitting an improved heat sink clamp and graphed the data yet again. Interesting. The original set up was obviously not clamped adequately as the diferential has increased to 19.5C with 1.21v and 11v to the internal and external TECs respectively.
Furthermore the increase in C/volt is closer to 0.6 - 0.5C. So the data in the previous post is rough at best. However, the relationship C/V remains linear 8 - 11volts (still waiting on a second DC-DC convertor to get lower voltage to the external TEC and graph the data further)
Above 11v there is no increase in differential because cooling of the copper strip to the hot side of the internal TEC has reached the optimal hot/cold side ratio, for the power ratings of the TECs and the thermal mass properties - I think?
As mentioned this set up seems to provide advantages over a brute force system, because a condition of cooling by the internal TEC is the production of heat near the camera chassis and the co-location of the TEC and sensor. I have not seen any sensor fogging as yet - localised warming near the sensor face.
I have noticed electroluminescence near the edge of the sensor in dark frames, but can't say whether this is related to the proximity of the cold plate -
here