 1. ## TEC undervolting charts

Attention: This post is not accurate, but it will hopefully be revised in the future to resemble some form of factuality.

Since peltier cooling power is nonlinear, calculating cooling power at voltages other than VMax can be difficult. To make life easy, I've assembled a chart of cooling powers for some standard TECs using the formula... snipped YAY REWRITE! OK, much thanks to shadowing on this one :-). the new formula is P=(I^2)R. P = wattage, I = amperage, R = resistance.
First, I derive the resistance from the manufacturer-provided numbers. then, using these, i make I x and get the wattages for each amp.
OK, since I was dead-tired when I was updating this whole chart last night, I didn't bother to give you guys the real formula used (derived from P=(I^2)R), so here it is (as it appears on my TI-83+):
\y1=(((x/16.1*8.0))^2)*(80/(8.0^2))
thats how it would look for the 80watt TEC listed below.
here is the article that, after reading through it several times late last night, yielded the equation.
Much to my surprise, my amperage draw approximations were pretty much dead on; it was the wattages that made no sense at all Keep in mind, these numbers are "rough guidelines" at best! Don't follow them too closely. I'd like to update this sometime soon with numbers that I'm more confident about, but I don't see that happening any time soon.

80 watt / 16.1 VMax / 8.0 IMax
5 volts: 5.7 watts; 2.48 amps
6 volts: 8.9 watts; 2.98 amps
7 volts: 12.8 watts; 3.47 amps
8 volts: 17.4 watts; 3.97 amps
9 volts: 22.8 watts; 4.47 amps
10 volts: 28.8 watts; 4.96 amps
11 volts: 35.6 watts; 5.46 amps
12 volts: 43.0 watts; 5.96 amps
13 volts: 51.2 watts; 6.45 amps
14 volts: 60.1 watts; 6.95 amps
15 volts: 69.7 watts; 7.45 amps
16 volts: 80 watts; 7.95 amps

120 watts / 24.6 VMax / 7.9 IMax
5 volts: 3.5 watts; 1.60 amps
6 volts: 5.5 watts; 1.92 amps
7 volts: 8.0 watts; 2.24 amps
8 volts: 10.8 watts; 2.56 amps
9 volts: 14.1 watts; 2.89 amps
10 volts: 17.9 watts; 3.21 amps
11 volts: 22.1 watts; 3.53 amps
12 volts: 26.7 watts; 3.85 amps
13 volts: 31.0 watts; 4.17 amps
14 volts: 36.4 watts; 4.49 amps
15 volts: 42.2 watts; 4.81 amps
16 volts: 48.5 watts; 5.13 amps
17 volts: 55.2 watts; 5.45 amps
18 volts: 62.3 watts; 5.78 amps
19 volts: 69.8 watts; 6.1 amps
20 volts: 77.8 watts; 6.42 amps
21 volts: 86.2 watts; 6.74 amps
22 volts: 95.0 watts; 7.06 amps
23 volts: 104.3 watts; 7.38 amps
24 volts: 114.0 watts; 7.70 amps

169 watt / 16.4 VMax / 16.1 IMax
5 volts: 15.7 watts; 4.90 amps
6 volts: 22.6 watts; 5.89 amps
7 volts: 30.8 watts; 6.87 amps
8 volts: 40.2 watts; 7.85 amps
9 volts: 50.9 watts; 8.83 amps
10 volts: 62.8 watts; 9.81 amps
11 volts: 76.0 watts; 10.79 amps
12 volts: 90.5 watts; 11.78 amps
13 volts: 106.2 watts; 12.76 amps
14 volts: 123.2 watts; 13.74 amps
15 volts: 141.4 watts; 14.72 amps
16 volts: 160.9 watts; 15.70 amps

172 watt / 24.6 VMax / 11.3 IMax (got the numbers from silverprop)
5 volts: 7.1 watts; 2.3 amps
6 volts: 10.2 watts; 2.8 amps
7 volts: 13.9 watts; 3.2 amps
8 volts: 18.2 watts; 3.7 amps
9 volts: 23.0 watts; 4.1 amps
10 volts: 28.4 watts; 4.6 amps
11 volts: 34.4 watts; 5.1 amps
12 volts: 40.9 watts; 5.5 amps
13 volts: 48.0 watts; 6.0 amps
14 volts: 55.7 watts; 6.4 amps
15 volts: 64.0 watts; 6.9 amps
16 volts: 72.8 watts; 7.3 amps
17 volts: 82.1 watts; 7.8 amps
18 volts: 92.1 watts; 8.3 amps
19 volts: 102.6 watts; 8.7 amps
20 volts: 113.7 watts; 9.2 amps
21 volts: 125.3 watts; 9.6 amps
22 volts: 137.6 watts; 10.1 amps
23 volts: 150.4 watts; 10.6 amps
24 volts: 163.7 watts; 11.0 amps

226 watt / 15.2 VMax / 24 IMax
5 volts: 24.5 watts; 7.89 amps
6 volts: 35.2 watts; 9.47 amps
7 volts: 47.9 watts; 11.05 amps
8 volts: 62.6 watts; 12.63 amps
9 volts: 79.2 watts; 14.21 amps
10 volts: 97.8 watts; 15.78 amps
11 volts: 118.4 watts; 17.36 amps
12 volts: 140.9 watts; 18.94 amps
13 volts: 165.3 watts; 20.52 amps
14 volts: 191.7 watts; 22.10 amps
15 volts: 220.1 watts; 23.68 amps

320 watt / 14 VMax / 26 IMax (these numbers were given to me by NoL, so if they're wrong, yell at him, not me)
5 volts: 40.8 watts; 9.3 amps
6 volts: 58.7 watts; 11.1 amps
7 volts: 80 watts; 13 amps
8 volts: 104.5 watts; 14.9 amps
9 volts: 132.2 watts; 16.7 amps
10 volts: 163.3 watts; 18.6 amps
11 volts: 197.6 watts; 20.4 amps
12 volts: 235.1 watts; 22.3 amps
13 volts: 275.9 watts; 24.1 amps
14 volts: 320 watts; 26 amps

OK, now, because wintsch labs gives conflicting information on this bad boy, theres 2 charts. I don't know which one is right, because wintsch labs is wierd. Here's the 32.8 IMax one; the second is the 25 IMax one.
437 watt / 26.7 VMax / 32.8 IMax
5 volts: 15.3 watts; 6.14 amps
6 volts: 22.1 watts; 7.37 amps
7 volts: 30.0 watts; 8.59 amps
8 volts: 39.2 watts; 9.82 amps
9 volts: 49.7 watts; 11.05 amps
10 volts: 61.3 watts; 12.28 amps
11 volts: 74.2 watts; 13.51 amps
12 volts: 88.3 watts; 14.74 amps
13 volts: 103.6 watts; 15.97 amps
14 volts: 120.2 watts; 17.19 amps
15 volts: 137.9 watts; 18.42 amps
16 volts: 156.9 watts; 19.65 amps
17 volts: 177.2 watts; 20.88 amps
18 volts: 198.6 watts; 22.11 amps
19 volts: 221.3 watts; 23.34 amps
20 volts: 245.2 watts; 24.56 amps
21 volts: 270.3 watts; 25.79 amps
22 volts: 296.7 watts; 27.02 amps
23 volts: 324.3 watts; 28.25 amps
24 volts: 353.1 watts; 29.48 amps
25 volts: 383.1 watts; 30.71 amps
26 volts: 414.4 watts; 31.94 amps

437 watt / 24 VMax / 25 IMax
5 volts: 19.0 watts; 5.2 amps
6 volts: 27.3 watts; 6.2 amps
7 volts: 37.2 watts; 7.3 amps
8 volts: 48.6 watts; 8.3 amps
9 volts: 61.5 watts; 9.4 amps
10 volts: 75.9 watts; 10.4 amps
11 volts: 91.8 watts; 11.5 amps
12 volts: 109.3 watts; 12.5 amps
13 volts: 128.2 watts; 13.5 amps
14 volts: 148.7 watts; 14.6 amps
15 volts: 170.7 watts; 15.6 amps
16 volts: 194.2 watts; 16.7 amps
17 volts: 219.3 watts; 17.7 amps
18 volts: 245.8 watts; 18.8 amps
19 volts: 273.9 watts; 19.8 amps
20 volts: 303.5 watts; 20.8 amps
21 volts: 334.6 watts; 21.9 amps
22 volts: 367.2 watts; 22.9 amps
23 volts: 401.3 watts; 24.0 amps
24 volts: 437 watts; 25 amps

I hope this chart is useful for somebody out there. If my equation for calculating these values is flawed in any way, please let me know! All of these TECs (except the 320 watt) are units sold either by dangerden or by frozenCPU and all numbers are taken from their specs.  Reply With Quote

2. Very nice and helpfull Can you include the power the TEC draws at certain volts? And maybe a TEC reated at 226.1w at 12v? (if you have the time for it)

Thanks in advance   Reply With Quote

3. Problem is that the power the TEC draws depends on the temperature differential over it...

So the hotter your waterblock then less current it will draw (lower DT) but worse temps.

Vice versa, reduce your water temp (and increase DT) then the TEC will draw more power.  Reply With Quote

4. you god that really helps when you cba to do the calculations... or find tec specs to do them do you have a table for a 320W 15V pelt?  Reply With Quote

5. updated with amperage approximations. anyone have the right info for the DD 172 watt pelt? their site just clones over the 120 watt pelt's specs.
I'll add the 320 watt pelt soon; got a link to a supplier? I can't seem to find any very easily.  Reply With Quote

6. Thermal Enterprises model CP1-12726

IDK if they have a website, if you email the guy named thermalenterprises on ebay he may be able to get the values for you. I am very interested in using one of these @5v.

Good to see im not the only one using big pelts at diff voltages EDIT:

Dividing amperage by the voltage you are running at is not a good way to predict amperage......How are you calculating that?

Just spot checking one example with the kryotherm software, you will be drawing 3.24A from the 80w unit at 5v. Would be interesting to see what is causeing this.

Qc seems to be about right though.  Reply With Quote

7. got a 320 here too, been looking around for a 5-10v variable PSU for it..   Reply With Quote

8. Originally Posted by ls7corvete
Thermal Enterprises model CP1-12726

IDK if they have a website, if you email the guy named thermalenterprises on ebay he may be able to get the values for you. I am very interested in using one of these @5v.

Good to see im not the only one using big pelts at diff voltages EDIT:

Dividing amperage by the voltage you are running at is not a good way to predict amperage......How are you calculating that?

Just spot checking one example with the kryotherm software, you will be drawing 3.24A from the 80w unit at 5v. Would be interesting to see what is causeing this.

Qc seems to be about right though.
for amperage i was just doing (voltage)/VMax*IMax.The results do seem kinda fishy though.  Reply With Quote

9. yea they arent matching with kryotherm so I would say that they are questionable.  Reply With Quote

10. Very Nice Info you got there. Can anyone verify this to make sure all the info is correct and no issues are to be had anywhere.

I ask as I want to make this a sticky, but most certainly want to make sure all the info is correct and there are no annotations that need to be added before I do.  Reply With Quote

11. The Imax is a bit wrong I think.

For example the Imax of the 80W pelt at 5v is 2.48A. Then it uses 12.4w at 5v? that must be wrong. I don't think your way to calculate the Imax is correct.  Reply With Quote

12. Originally Posted by Bloody_Sorcerer
..................

437 watt / 26.7 VMax / 32.8 IMax
5 volts: 148.3 watts; 6.14 amps
6 volts: 174.3 watts; 7.37 amps
7 volts: 199.1 watts; 8.59 amps
8 volts: 222.6 watts; 9.82 amps
9 volts: 244.9 watts; 11.05 amps
10 volts: 266.0 watts; 12.28 amps
11 volts: 285.9 watts; 13.51 amps
12 volts: 304.5 watts; 14.74 amps
13 volts: 321.9 watts; 15.97 amps
14 volts: 338.1 watts; 17.19 amps
15 volts: 353.0 watts; 18.42 amps
16 volts: 366.8 watts; 19.65 amps
17 volts: 379.3 watts; 20.88 amps
18 volts: 390.6 watts; 22.11 amps
19 volts: 400.6 watts; 23.34 amps
20 volts: 409.4 watts; 24.56 amps
21 volts: 417.0 watts; 25.79 amps
22 volts: 423.4 watts; 27.02 amps
23 volts: 428.6 watts; 28.25 amps
24 volts: 432.5 watts; 29.48 amps
25 volts: 435.2 watts; 30.71 amps
26 volts: 436.7 watts; 31.94 amps
............................................
Impressed with accuracy of 437 table. I'm using a 437W at 19.9V. Current draw is 24.4A.

EDITED for brevity  Reply With Quote

13. I'm fairly confident that my wattage numbers are correct, but obviously something is wrong with the amperages. Currently, I'm looking for a better equation to calculate them. Still missing IMaxes for 320watt and 172watt TECs.  Reply With Quote

14. for the 320, its 26 amps.  Reply With Quote

15. gah, these amperages are driving me crazy! I had been trying a method in which i took the % efficiency of the peltier (watts drawn / watts cooled) and multiplied that by the new watts cooled and then divided by the new voltage, which seemed to work mostly, until i tried it on the 437watt tec,where it went absolutely bonkers, suggesting that it draws 50-plus amps at 12volts, something i highly doubt. I'm also starting to think that it's amperage figure is totally wrong, too. I doubt that a 437watt tec draws 875 watts at VMax.  Reply With Quote

16. they lose efficiency as voltage increases.. it might be near to that.  Reply With Quote

17. Thanks Sorcerer!   Reply With Quote

18. bloody when ur 98% confident its all right shoot me a PM and I will sticky it. until then its a WIP.  Reply With Quote

19. you can try kryotherm calculator for the amps.

I think amperage is gonna vary too much to make a chart.  Reply With Quote

20. I'm declaring this done. Amperages are all approximate. huge thanks again to shadowing :-)  Reply With Quote

21. What about 350 watt peltiers? But great stuff man. Thanks a bundle.  Reply With Quote

22. w00t! updated! finally got numbers for 172 watt TECs (from silverprop's e-store) and used numbers from NoL (who got them from eBay) for 320 watt TECs, so those could be wrong :-P
this was supposed to get updated last night, but i left my TI-83+ in school...
if anyone wants them, I'll but the exact equations i used for each TEC in.  Reply With Quote

23. where can i find a 320w pelt in the usa  Reply With Quote

24. Ebay thermoelectric enterprises  Reply With Quote

25. When were the values changed?

The wattage values are completley wrong, they need to be changed, they seemed pretty close before.  Reply With Quote

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