Quote:
Originally Posted by ZeroID
Note that todays experiment was without forced cooling by fans or coolant and even at 12 volts I could still place my hands on the fin array and the copper tubes near the base plate were hot but not unbearably so.
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How good is a water-cooled CPU cooler module without fluid coolant? I would have thought that the heat path being restricted to just 4 copper tubes might really cut its passive heat exchange capabilities?
I've ordered a similar 12V / 60W TEC for my ASI120MC (mine was only $1.91 from eBay China - including postage
), and a more conventional flat "passive" heat-sink with protruding "pins" (see attached photo) - I'm hoping that the good head conduction from the hot side of the TEC straight to the heat-sink pins will allow good heat exchange to achieve satisfactory cooling without needing any fan to shed the heat load.
I'm going to wrap my camera in a cut-off stubby cooler (as you have done) to provide insulation, and I was thinking I might need to use a silica sachet to control dewing on the IR-cut filter - maybe even two, one inside and one outside the IR-cut?
I hadn't really thought about the issue of the TEC trying to cool the whole focuser assembly by conduction - I guess I'll just have to wait and see what transpires!
The datasheet for my TEC suggests I should be able to reach a Delta-T of about 40 deg C at 6 volts, or close to 70 deg C at 12 volts. Assuming the heat sink can keep the hot side to around 40 to 50 deg C, I should be able to get down to at least 20 deg C below ambient without too much trouble, meaning 0 deg C (or maybe single-digit negatives?) at the sensor. (I'm in Brisbane - it's a rare night that ambient temperatures are in the single digits!)
I might need a bigger battery if I want to run as 12 volts, though - it will pull about 5 amps at 12 volts, so my 7.2 A.hr battery will be exhausted in less than an hour.
I'm hoping performance is satisfactory at 6 volts, which should mean I can run both the TEC and the scope for several hours. If I need to run at 12 volts to get adequate cooling, I guess I'll buy one of those car jump-starter packs - so much for this being a cheap hack!
More to follow when the bits arrive, and I can get it set up.