Hi... I have simple peltier setup.. here is the data


8Amp/70w Peltier Module

Ambient 85F (30C)
Heat sink hot side 90F (32C)
Cold Side (only with plain copper attatched to it) 59F (14C)


I want the Cold Side colder, around freezing point....

I know peltiers go cold on one side, but if the hot side goes too hot, then the cold side also gets hot (or less cool anyway)

when does the cold side start becoming hot?

is my heatsink/fan combo at its limit?

basically was wondering if my heatsink/fan will be able to handle a 170W peltier element.

What CPU do you have? 70W is not enough for a pelt. Try Upgrading your pelt first, maybe around 100 to 120Watts.

But those really arent bad temps, but those temps can be reached with a good watercooling system.

The cold side starts becoming hot when the heatsink cant take away anymore heat.

Your better off with a watercooling-Pelt setup.

Quote: Originally Posted by Nerdz What CPU do you have? 70W is not enough for a pelt. Try Upgrading your pelt first, maybe around 100 to 120Watts. But those really arent bad temps, but those temps can be reached with a good watercooling system. The cold side starts becoming hot when the heatsink cant take away anymore heat. Your better off with a watercooling-Pelt setup.

hi, this is not for a CPU, rather for cooling electric motor...Racing electric cars, dont wanna go the water cool method as yet, need to keep it simple and small as possible... i am using i think a old P4 Radiator, here are some pics....

i would expect my Peltier Hot side go up another 10deg C to 15degC if i used a 170W peltier? and hopefully dropping the cold side by another 10C, and it should frost..... would a hot side of say 45degC be too hot?

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Dont forget that What ever is picked up on the cold side, the hot side has to handle, and the heatsink has to handle both loads. So if your motor is disapating say 70w, and the pelt disapated another 70, that 140W the heatsink has to get rid of.

The max of a pelt (most pelts) on the hotside is around 85C. Id say 60C is the max SAFE temp I would go.

Is that a 120mm Fan? If it is I can hook you up with a good fan that blows 160CFM at 24V at a pretty cheap price.Whats your current CFM on that fan?

You should try to put 2 fans on that thing if you can.

You may need a HSF with a greater surface area (that can dissipate more heat). If the "hot" side of your TEC(pelt) is getting too hot, then it starts to warm up the "cold" side as well, and at that point the pelt is working against itself.

Since your HSF looks pretty big to begin with, you can always try pelt stacking, where you just get another TEC (preferably similar wattage as the one you already have) and stack them, hot side --> cold side. This technique has been used before... the secondary "stacked" TEC cools the primary TEC further, and your HSF cools the secondary TEC.

On con to this setup is that is doubles the appetite of your already power-hungry cooling setup. However, you may be able to push your temps below or near freezing with this setup. It's just an idea if you still don't want to cool that TEC with water.

BTW- As I'm sure you're already aware, 60F isn't quite cold enough to worry about condensation, but if you push that pelt any colder(say 10-15F), you're gonna have to make sure you insulate properly to prevent condensation and frying your hardware. I'm sure you already know this, just wouldn't want you to blow your system up after successfully reaching near freezing temps.

hi, the fan is a FoxComm 70mmx70mm, its DC12v/0.45A not sure on the CFM rating. I may try doubling up the fans.

My hotside heatsink is 80x80x 7mm copper

also with my electric motors, I just want to chill the motor BEFORE i run them, not during the run. So the there is no extra heat that needs to be disspated from the motor.

I read up on stacking the Peltiers http://www.overclockers.com/tips313/ but was told its not very efficient, and a better way was just to use a bigger rated Peltier.

Oh... for racing model car motors, hmm... Those must be some hot motors to need to cool them with a pelt! Well, yeah stacking pelts isn't the epitome of effieciency, but it was just an idea.

Question tho:
If you're just "chilling" them before a run, why would you need a huge pelt? If the motor isn't producing any heat, it'll get pretty cold if you leave it there for a while. You could always drop your motors in an ice chest full of dry ice!

btw- I've got a couple 4" square heatsinks that I used for a pelt once that can fit a TEC about 1-3/4" square between the mounting screws. I can email you some pics if your interested. I was fiddling with a pelt and it came with these fairly large heatsinks and I was able to cool it pretty darn good. LMK.

You should be able to get a 80mm fan on that thing. You can also stack fans to get more CFM. But try to get a 120 to 80mm Fan Adapter or a 120mm to 60mm Fan adapter.

Quote: Originally Posted by Jobistober Oh... for racing model car motors, hmm... Those must be some hot motors to need to cool them with a pelt! Well, yeah stacking pelts isn't the epitome of effieciency, but it was just an idea. Question tho: If you're just "chilling" them before a run, why would you need a huge pelt? If the motor isn't producing any heat, it'll get pretty cold if you leave it there for a while. You could always drop your motors in an ice chest full of dry ice! btw- I've got a couple 4" square heatsinks that I used for a pelt once that can fit a TEC about 1-3/4" square between the mounting screws. I can email you some pics if your interested. I was fiddling with a pelt and it came with these fairly large heatsinks and I was able to cool it pretty darn good. LMK.

having ice is ok, but then i have to take the motor off the car, whereas the design i did with the clamp, goes straight on the motor. its a common device that is used in rc-racing.

the current peltier i get the copper plate to around 15degC, and if i leave it on the motor for about 30minutes i can get the motor to about 22degC (bit of efficiency loss as the copper plate only sits on the motor not permanatly bonded) so i would like the peltier to be like 0degc, so i can hopefully get my motor around 5degC


motors run up to 70degC, and since we only run them for 5minutes per race, if the starting temp of the motor is 5degC, then at the end of the 5 minutes it will be much lower, than if the starting temp was at 29DegC.

p.s i live in sydney australia, so i dont think it will be efficient to buy it off you... i would like to have a look anyway... email me at "kyoshokev at gmail dot com"

Quote: Originally Posted by Nerdz You should be able to get a 80mm fan on that thing. You can also stack fans to get more CFM. But try to get a 120 to 80mm Fan Adapter or a 120mm to 60mm Fan adapter.

yeah i'll put a fan that "blows" the air away, and also a fan that "sucks" the air from the radiator.

Quote: Originally Posted by Gofyah p.s i live in sydney australia, so i dont think it will be efficient to buy it off you... i would like to have a look anyway... email me at "kyoshokev at gmail dot com"

I'll shoot ya a couple pics tomorrow after work.

Along with 120 fan a heatsink that is contured to shape of motor on peltier-motor side made from alluminium may increase efficient use.(maybe?)jo

Ya, if the heatsink was curved to match the shape of the motor, then you'd get more surface area contacting between the motor and the HS, so you'd get better heat transfer.