Completed Project Peltier Module TEC1-12706 draws only 2.7A. Is it normal or my unit is defective?

Thread Starter

Rahulk70

Joined Dec 16, 2016
536
Hi guys,

I had recently ordered a TEC1-12706 Peltier module from amazon. I tested the module as soon as I recieved with a 1.2V Ni-Cd to make sure its working and also to make sure of the hot and cold sides. I purchased it for a small mini cooler project.So, attached the Peltier module to a CPU heat sink with fan and the cold side with a small aluminium block and added the necessary insulation etc. and I was able to cool down a small beaker of boiled hot water to ice cold, though it didn't freeze.I ran the unit for like 45 minutes. The unit was powered with a 12.61V-2400mAh (3 Cell Li-ion ICR18650-24E) pack. The initial current draw was around 3.8A but quickly dropped to 2.6-2-7A and remained stable.Tried bumping up the voltage to 14V and current draw increased to 4.3A but reduced it back since I didn't was to ruin the module. So, is it normal for the device to run at just 2.7A current draw ? because most people on the internet who brought 12706 say the current draw is 4A and above at 12V.

Thank You
 
Last edited:

wayneh

Joined Sep 9, 2010
17,498
That seems a bit low but it's probably fine. There are a few things going on and you need better data to be sure. You need to measure current, ∆T and temperature on both sides – all at the same time – before you can be sure the unit is outside of specifications. The apparent resistance is fairly constant but will change somewhat with T, ∆T, and applied voltage.

You need to consider that a TEC is much more efficient at current levels well below the specified maximum. At max, it moves only about one unit of heat for every ten it consumes. All 11 units of heat appear on the hot side and it takes a lot of care to make sure that heat gets carried away. The temperature of the cold side is limited by the temperature of the hot side.
 

Thread Starter

Rahulk70

Joined Dec 16, 2016
536
That seems a bit low but it's probably fine. There are a few things going on and you need better data to be sure. You need to measure current, ∆T and temperature on both sides – all at the same time – before you can be sure the unit is outside of specifications. The apparent resistance is fairly constant but will change somewhat with T, ∆T, and applied voltage.

You need to consider that a TEC is much more efficient at current levels well below the specified maximum. At max, it moves only about one unit of heat for every ten it consumes. All 11 units of heat appear on the hot side and it takes a lot of care to make sure that heat gets carried away. The temperature of the cold side is limited by the temperature of the hot side.
Thanks. I'll take more measurements and check with the datasheet how its performing. Initially I had this big heat sink with fan attached to it: http://www.ebay.com/p/HP-Dc7900-SFF-Processor-Heatsink-480368-001/1700473392
then I replaced it with this: https://www.amazon.com/INTEL-A65061-002-SOCKET-478-A65061-002/dp/B00CD44IU4
and the heat gets sufficiently removed I assume as the cold side does get cold but not like ice cold as the ones shown on most Youtube videos.Today I'll try keeping the hot side heat sink in an ice bath and see if there is any change in current draw and also if the cold side can get below 0 degree Celsius.
 

Thread Starter

Rahulk70

Joined Dec 16, 2016
536
Have you checked the datasheet?
This is a 50W TEC. 4A@14V sounds about right to me.
I would say if you can get down to ice cold it is working.
I didn't run it at 14V for more than a couple of seconds fearing I would damage it. It definitely gets really cold.I tried without the cooler aluminium block on the cold side to see if there is ice formation like on those Youtube videos, but it ain't working. So, like in my above post gonna see to get the hot side temp below 32F. :). Maybe I'll have some luck there!!
 

Thread Starter

Rahulk70

Joined Dec 16, 2016
536
Does the current normally change as it gets going? The data sheet states a maximum but not a working current.
Yes, it does.Initially when its connected to the 12.5V pack the current draw ranges from 3-3.5A. but as the cold side gets colder it immediately drops to 2.5-2.3Amps.
 

Thread Starter

Rahulk70

Joined Dec 16, 2016
536

Attachments

Thread Starter

Rahulk70

Joined Dec 16, 2016
536
Update:

Guys. Tried placing the heatsink of the hot side in an ice bath.Now the cooler got really cold so fast.I mean really fast. the cold side samll aluminium cabinet was really cold if I waited for sometime maybe I could I obtained some ice I guess.Though the current draw measurements where the same as the previous ones.
 

Thread Starter

Rahulk70

Joined Dec 16, 2016
536
It's a good idea, yes, but there is far less heat moving across that interface than across the hot side interface.
Thanks. I'll try and post the results. Initially I thought of adding thermal paste on the cold side too but since there is presence of moisture when it gets really cold I thought it might get messy or leak.
 

wayneh

Joined Sep 9, 2010
17,498
Thanks. I'll try and post the results. Initially I thought of adding thermal paste on the cold side too but since there is presence of moisture when it gets really cold I thought it might get messy or leak.
Well, any moisture is coming out of the air as condensate. There should be no opportunity for condensation to touch the TEC. A little paste may help keep moisture out of the interface.
 

Thread Starter

Rahulk70

Joined Dec 16, 2016
536
Well, any moisture is coming out of the air as condensate. There should be no opportunity for condensation to touch the TEC. A little paste may help keep moisture out of the interface.
Thanks.I'll apply some on the cold side too.Is moisture really bad for the module? I mean like even if its sealed with silicon from the sides.
 

Thread Starter

Rahulk70

Joined Dec 16, 2016
536
Sorry for this noob question.Is 6 Amps is the max current draw for the module at its Vmax=15V or is it the the current that the module must draw at 12V?
 

MrChips

Joined Oct 2, 2009
31,055
Sorry for this noob question.Is 6 Amps is the max current draw for the module at its Vmax=15V or is it the the current that the module must draw at 12V?
I would take it to mean put more than 6A into the unit at your own peril.
Moreover, do not exceed the 75°C temperature differential between the hot side and cold side.

With sensitive semiconductor devises such as TECs it would be wise to derate the specs by 20-50%.
 
Top