Peltier heat pump questions

[Ribenapigeon]

I bought a peltier heat pump to play around with.
https://www.amazon.co.uk/TEC1-12706-Thermoelectric-Peltier-Cooler-Volt/dp/B00APB96S6/ref=sr_1_1?ie=UTF8&qid=1392638829&sr=8-1&keywords=peltier

I first tried it with a 12v 1A supply. Not very impressive results. At ambient room temp of 20c I got 16c to 18c on the cool side and around 23c to 25c on the hot side. I was using a heat-sink on the hot side with a pc fan drawing air over it. So a temperature difference of around 7c.

So I attach the device to an old car battery charger (2.7 A, 12v). Then things got more interesting. The Peltier device drew 2.5A off the charger and immediately the cool side temp drops to less than 5c and the hot side goes up to over 35c. But then within seconds the temp on the cool side starts rising and the hot side as well. The cool side going up past ambient (20c) and on into the 30c+ range and the hot side over 50c. I didn't leave things to see what would happen and cut the power.

So what happened? can anyone explain the drop then rise when I attached to a higher amp supply. The Peltier Device is rated for 6A so I dont think I over cooked it. I did eonder if maybe my fan heatsink combo was not cooling the hot side fast enough and that this might cause the problem but seeings these devices are used commonly in pc cooling I would have thought the heatsink pc fan cooling system would be fine.

Any ideas?

these are the Peltier specs

TEC1-12706 Thermoelectric Cooler Peltier 12V 60W

1.Voltage: 12V
2.Umax(V): 15.4V
3.Imax(A): 6A
4.Qmax(W): 92W
5.Dimensions: 40mm x 40mm x 3.6mm

[fatpies]

You aren't using AC are you?


IIRC from my experimentation decades ago, the more you put into it, the more you need to take off the hot side. That's because if you pump 500 W of DC power into it, and you cool 300 W on the cool side, you will have to dump 800 W of heat on the hot side.

Plus heat travels, and thus if you aren't separating the plates with something it will simply convect over to the other side, negating any cooling.
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[Ribenapigeon]

Nope its DC off both transformers.

[WD Forte]

Maybe you just got a bad one?

Sounds like it was happy on the wall wart with limited current/heat but the 'old battery charger' killed it.

This battery charger, tranformer or switched mode ?
Old transformer types can be a bit rough and ready on semiconductors.
are you sure it has a nice clean DC output with no spikes
or transients?
and how are you measuring the voltage and current?
Again, an old charger can be quite iffy as a PSU, any meters on them should be regarded with suspicion.

A bench power supply where you can dial in a more precise voltage and have current control would be more reliable.
Nice if you have /can afford one.

Did you use thermally conductive paste twixt the device and heat sink?
If it was only partially absorbing some of the heat there may have been a hot spot which killed it.
Not sure how rugged or forgiving they are TBH
I do know the ones I played with in a beer fridge had fookin great heat sinks on both sides plus fans on the hot side to absorb and dissipate the heat.


Sound like you joined the
Ere! these things sposed to smoke like that? club
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bikers smell of wee

[dydey90]

I always think these are weird little devices.

I keep wondering if you could use them to generate power if you stuck the cold end outside and kept the hot end indoors...
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[Ribenapigeon]

[Ribenapigeon]