Peltier

Thread Starter

Eddieg6996

Joined Apr 8, 2021
8
Hello to everyone, im having trouble powering a 0.82v peltier with a 4v dc micro fan. I hooked up red wires and black wires together on the fan and the peltier and nothing happens. If i put a 9v battary just to the peltier the battery gets hot and peltier not getting cold. Any help would be appreciated
 

wayneh

Joined Sep 9, 2010
17,031
Hello to everyone, im having trouble powering a 0.82v peltier with a 4v dc micro fan. I hooked up red wires and black wires together on the fan and the peltier and nothing happens. If i put a 9v battary just to the peltier the battery gets hot and peltier not getting cold. Any help would be appreciated
A peltier needs a lot of current, several amps depending on the size, and a typical little 9V can't come close.
What size module do you have? Do you have any of it specs?
 

Thread Starter

Eddieg6996

Joined Apr 8, 2021
8
Yes thanks for your help 2 Fans Specifications:
Operating Voltage: 3-5V
Operating Current: 0.15A
Speed: 31,500 RPM---(3V)
53,000 RPM---(5V)
Motor Diameter: 8..5mm

1 Peltier is
  • Cooling or heating by changing current direction
  • Model: TEC1-00703
  • Max. Current: 3.3A
  • Max. Temperature Difference: 67 deg C
  • Max. Voltage: 0.82V
  • Max. Refrigerating Power: 1.6W
 

wayneh

Joined Sep 9, 2010
17,031
  • Max. Current: 3.3A
  • Max. Temperature Difference: 67 deg C
  • Max. Voltage: 0.82V
  • Max. Refrigerating Power: 1.6W
That's a relatively small TEC. Getting enough current at that low voltage is tricky. I'd be tempted to use a 5V or 12V supply (such as a used computer PSU) with a lightbulb in series with the TEC. This would limit the current thru the TEC to the current in the lightbulb.

What are you trying to do with your TEC?
 

Thread Starter

Eddieg6996

Joined Apr 8, 2021
8
A peltier needs a lot of current, several amps depending on the size, and a typical little 9V can't come close.
What size module do you have? Do you have any of it specs?
Yes thanks for your help 2 Fans Specifications:
Operating Voltage: 3-5V
Operating Current: 0.15A
Speed: 31,500 RPM---(3V)
53,000 RPM---(5V)
Motor Diameter: 8..5mm

1 Peltier is
  • Cooling or heating by changing current direction
  • Model: TEC1-00703
  • Max. Current: 3.3A
  • Max. Temperature Difference: 67 deg C
  • Max. Voltage: 0.82V
  • Max. Refrigerating Power: 1.6W
 

Thread Starter

Eddieg6996

Joined Apr 8, 2021
8
That's a relatively small TEC. Getting enough current at that low voltage is tricky. I'd be tempted to use a 5V or 12V supply (such as a used computer PSU) with a lightbulb in series with the TEC. This would limit the current thru the TEC to the current in the lightbulb.

What are you trying to do with your TEC?
Hello and thx for the help, trying to make a mini cooling device. I put the peltier on a large heatsink but it barley get cold to the touch. Im trying to get it to frost up, i seen a video were he used 1 AA battery with a big 20mm peltier with a 20mm computer fan and that worked. Just confused why a smaller battery wont work even for a short time
 

wayneh

Joined Sep 9, 2010
17,031
Hello and thx for the help, trying to make a mini cooling device. I put the peltier on a large heatsink but it barley get cold to the touch. Im trying to get it to frost up, i seen a video were he used 1 AA battery with a big 20mm peltier with a 20mm computer fan and that worked. Just confused why a smaller battery wont work even for a short time
Some AA batteries are capable of a high current discharge. It probably shortens their life but it can be done. A 9V battery usually cannot reach that current despite the higher voltage.

The ∆T you observe is proportional to the current supplied. Note that both sides may get hot if you don't keep the hot side cool enough. Peltier cooling can be very inefficient, with only one heat unit moved for every ten consumed. One gets removed from the cold side while eleven show up on the hot side.
 

Thread Starter

Eddieg6996

Joined Apr 8, 2021
8
TEC1-00703
Max. voltage: 0.82V
Max, Power: 1.6W

I think you already killed it.
Whats the smallest microcontroller that would allow me to control v and current on both fans and peltier? I was thinking about using the adafruit trinket, would that allow me to accomplish this?
 

wayneh

Joined Sep 9, 2010
17,031
Whats the smallest microcontroller that would allow me to control v and current on both fans and peltier? I was thinking about using the adafruit trinket, would that allow me to accomplish this?
A Trinket would be fine but it won't solve your power supply problem. No MCU is going to control that much current directly. But you could use temperature sensors and then PWM to drive a MOSFET for the TEC current, for example.
 

MrChips

Joined Oct 2, 2009
23,073
A Peltier thermoelectric module is a heat pump. It pumps heat energy from one side to the opposite side.
The temperature on one side rises while the temperature on the other side falls, up to a point.
If you do not remove heat from the hot side fast enough, thermal conduction overwhelms the cooling effect and the whole device warms up. If you exceed the maximum power dissipation of the device it is destroyed.

Do the math.

Power P = V x V /R
R = V x V / P = 0.82V x 0.82V / 1.6W = 0.4Ω

A 9V battery tries to push 22A into the device. It tries as best as it can and instantly destroys the Peltier device.
Ever tried pushing 200W into a 1.6W light bulb?
 

wayneh

Joined Sep 9, 2010
17,031
It tries as best as it can and instantly destroys the Peltier device.
I think it's the other way around, the Peltier is a short as far as the battery is concerned. The Peltier can survive 3.3A but the battery can't reach that. Of course that depends on the battery. A NiCd might, but I don't think a typical alkaline will.
 

Thread Starter

Eddieg6996

Joined Apr 8, 2021
8
The TS didn't mention burning himself (yet), so hopefully he still has his Peltier. We'll see...
Oohh ya I have burnt myself many times trying to figure this out lol. But its fun, im just beginning and now im addicted to making things. First I need to understand how to manage current and voltage and how to do the math that all you pros know.
 

wayneh

Joined Sep 9, 2010
17,031
Oohh ya I have burnt myself many times trying to figure this out lol.
That may explain why you didn't feel any cooling. A TEC can produce a ∆T across itself. It doesn't care if both temperatures are hot or both cold, all it knows is ∆T.

If the hot side is really hot, which happens pretty quickly, the "cold" side will be a much lower temperature but still hotter than ambient and hot to the touch. This is a predictable observation for a "naked" TEC without care taken to cool the hot side to keep it near ambient. When first powered the cold side may briefly go below ambient before the hot side heats up, and then both sides go far above ambient and you get a burnt finger.

Try placing the hot side against a block of aluminum and press down on the cool side. You should definitely feel cooling before the heatsink warms up. Don't plan to leave a TEC connected to power for more than a few seconds unless/until you can deal with getting the heat away from the hot side.
 
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