The Buck convertor arrived, with two more on order rated at 6 amps. A cost/time effective way to cater for the various voltage/distribution requirements of my setup. The footprint is very small. Given the steady temp sensor readings these convertors are quiet.
http://www.ebay.com.au/itm/130892021...84.m1497.l2649
http://www.ebay.com.au/itm/300688545...84.m1497.l2649
Rated at 5A, input is quoted as minimum 10V - but works down to 8V. Output 0.9 volts minimum, which permits setting the internal TEC at 1.2v (see previous post). An external TEC can be used to control temperature through a second convertor. If small differentials are required in the colder months both convertors can be wound back as required.
In pursuing a linear method of temperature control, buck convertors seem to be the way to go. Essentially, they provided a means of setting a differential, but not a set temperature. As previously explained temperature variations can be handled within reason by dark scaling and any mismatch artifacts dithered out during acquisition of light frames. Aggressive dithering of light frames is a prerequisite for high SNR DSLR images.
The heatsink, fan ON or OFF, handles heat dissipation well, which tells me it can be smaller, providing it's active. Perhaps a relay to turn off cooling in response to fan failure, for protection.
BTW: Tellurex make a 25 x 12mm module only 3.4mm deep rated at 2.5 amps - ideal for the internal TEC application, but I cant find a reseller. Presently, I'm waiting on Tellurex to suggest an alternative shipping method other than the single $97 dollar option for delivery to Aus. Lets see if they come through? The dimensions of this module offer a few more options in terms of room for better insulation of warm/frigid components from the camera body.