TEC undervolting charts

[Bloody_Sorcerer]

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.

[alexio]

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

[Holst]

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.

[shinymod]

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?

[Bloody_Sorcerer]

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.

[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.

[Bloody_Sorcerer]

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.

[Premmer]

for amperage i was just doing (voltage)/VMax*IMax.The results do seem kinda fishy though.

If your 320W undervoltage table is referring to the Thermal Enterprises CP1-12726, suspect it needs a major rework.

Referring to Page 2 of the Thermal Enterprises documentation on the CP1-12726, the graph in the upper left hand corner plots Qc(W) vs dT(C). Look at the intersection point of the I=26A plot with the y-axis scaling of Qc. The value indicated validates the Qcmax noted on Page 1 of 243.5W. This device has a maximum cooling rating of 244W (Th = 27C), in round numbers, at a maximum input power consumption level Pcmax of (15.4V*26A)W.

The 320W Qcmax rating is at a Th = 50C. This would require a Pcmax level considerably greater than (15.4V*26A)W.

[ls7corvete]

If your 320W undervoltage table is referring to the Thermal Enterprises CP1-12726, suspect it needs a major rework.

Referring to Page 2 of the Thermal Enterprises documentation on the CP1-12726, the graph in the upper left hand corner plots Qc(W) vs dT(C). Look at the intersection point of the I=26A plot with the y-axis scaling of Qc. The value indicated validates the Qcmax noted on Page 1 of 243.5W. This device has a maximum cooling rating of 244W in round numbers, not 320W which I believe is hype, at a maximum power consumption level of (15.4V*26A).

If there is a 50mm square 320W Qcmax peltier in the marketplace, it's not this one.

Hmmmm is there one? I still believe this is the most powerfull 50mm.

[Premmer]

I still believe this is the most powerfull 50mm.

That may be but lets refer to the device by its actual Qcmax rating, 244w.

I emailed Thermal Enterprises and posed the following question.
"Your ebay advertisement refers to the device as 245-320w. Your specs clearly state that the maximum Qc of the device is 243.5w . Why do you use the 320w reference in your advertisement? It's misleading to the public".

Their response was as follows.
"We simply follow the same common practice as most other TEC manufactures, we establish the watt rating of our devices under two different operating conditions. The lower wattage rating is established with hot side temperature at 27 deg C. The higher wattage rating is established with hot side temperature at 50 deg C".

After researching the peltier rating subject, I have to agree with Thermal Enterprises response. It is up to the end-user to determine which set of peltier parameters would be most applicable for their operating conditions.

In summary, when peltier maximum cooling power wattage ratings (Qcmax) are expressed by two values as is the case with Thermal Enterprises devices, the lower rating equates to a Th = 27C ambient condition and the higher rating to a Th = 50C. In any well planned CPU peltier/water-cooled system, the Qcmax that would be most representative of their system's cooling performance would be the vaule at Th = 27C.

[STEvil]

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

[ls7corvete]

yea they arent matching with kryotherm so I would say that they are questionable.

[MaxxxRacer]

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.

[alexio]

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.

[raypsi]

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.

Not only is a TEC a heater/cooler, it also is a thermal pile generator. The generator counters the TEC effect. Increasing the internal resistance, there by lowering the current drawn by the TEC. I could get nowhere near the current spec for a 169w TEC, with my set up.
44C on the hot side and
-1.0C on the cold side.
only air loading the cold side.
ambient temp at 25C
slot A dual fan heat sink on the hot side.
I was pulling less than 7 amps
at 13.4 volts

[Premmer]

..................

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

[Bloody_Sorcerer]

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.

[ls7corvete]

for the 320, its 26 amps.

[Bloody_Sorcerer]

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.

[STEvil]

they lose efficiency as voltage increases.. it might be near to that.

[Mr. Tinker]

Thanks Sorcerer!

[MaxxxRacer]

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

[ls7corvete]

you can try kryotherm calculator for the amps.

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

[Bloody_Sorcerer]

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

[n00b 0f l337]

What about 350 watt peltiers? But great stuff man. Thanks a bundle.