Quote:
Originally Posted by TiGa
I saw 2 groups in parallels with only 2 wires going in the block. I deduced that they would split in parallels again. Deduced being the keyword here.
I don't know much about TECs yet so 6x12Vx1A=72W made more sense to me than 6x4Vx3A=72W.
Please correct me anytime if I'm wrong.
TiGa

Firstly I must say i have never had, and probably never will have a freezone, an eliminator or any other cooit products. My deductions on wiring are purely from my electrical engineer training of 20 ODD years ago and recent use of TEC's.
Yes here we go again...Ohm's law.
These are semiconductors Ohm's law doesn't work to well.
Well to start if a peltier draws 6amps at 15.6v there is no way it will draw only 1 amp at 12v. The volt/amp relationship is about the only roughly "linear result" with TEC's hence it is possible to get ballpark figures using Ohm's law (it is a "linear" calculation.) so you see at 12v a 15.6v TEC (75% power roughly.) will draw about 75% of the max current (6amps.)....not 1 amp...by any means. (note the more you undervolt the more the result deviates from linear.)
When using multiple TEC's you have to decide on the circuit first (serial/parallel arrangement.) Each parallel leg must have the same number of the same type of TEC. Then calc the voltage per TEC then use a performance chart to get the current and from there use a Qc (pump) chart to get the actually pump at that operating point and temperature and then the calculation to 72w will make perfect sense.
6 tec's in series is too low a voltage.
To have an equal no of tec's on each leg that is 3 parallels of 2 or 2 parallels of 3.
3 parallels would give a voltage of 6v per tec so the current would be too high..theoretically 3amps. (theorectically 9 amps for complete circuit....to much for molex connection.)
So 2 parallels would give us 4v per TEC for a draw of something like 1.5amps (theoretically 3amps for the circuit)
giving about 4.5 amps for the control circuit and the fan/pump to stay under the 8 amps for a molex connection. This is quite a lot that is why i think they use 12708 which will give a slightly higher pump. Plus the fact that 12708 is one of the most widely available being made by all manufactureres and consequently pretty cheap.
I say
theoretically here because when
using multiple TEC's you really do need to use performance charts for the current draw and pump. The way parallel circuits affect the current... to be 0.51amp or more out with your initial ballpark figures can skew everything.
Edited by zipdogso  5/11/09 at 5:15am