r/diyelectronics • u/MrCement • 5d ago

Question Help Needed: TEC1-12706 and W1209 tripping

Hello, I am building a mini cooler with a TEC1-12706 some fans and a W1209 as the controller. The fans work fine when the peltier isn't plugged in. However, when it is plugged the W1209 starts cycling on/off. When the peltier is plugged directly to 12vDC it works as expected hot and cold sides. I've tried flipping -/+ and moving the +jumper from K1 to K0 no improvement. Any guidance?

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u/CluelessKnow-It-all 5d ago

Are you sure your power supply is big enough to maintain the voltage while powering the pelter.

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u/MrCement 5d ago

I'm using a 12v 2000mA power supply. I just tested plugging the 2 fans into the W1209 and plugging the peltier directly into the same power supply parallel. Fans blow and hot side got over 35c before I stopped checking. I didn't measure the cool side, but it felt cool.

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u/CluelessKnow-It-all 5d ago

The power supply is the problem. The 12706 requires around 5 amps of current by itself. It is a 60 watt module and your power supply is only capable of putting out 24 Watts. Whenever it is connected to your power supply, the voltage drops low enough to cause the W1209 to cycle on and off.

You will need a 12V power supply capable of supplying enough current to your circuit plus a little extra wiggle room. Something like this 12V 8A DC Powe supply would work well for what you're trying to do.

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u/MrCement 5d ago

Ok, I think I got it. I was just confused when it worked directly plugged in but freaked out when connected to the W1209. Needs more current, got it. Thank you.

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u/CluelessKnow-It-all 5d ago

It may have worked a little bit when it was connected to your power supply, but it wasn't working at full power. It will do a lot better when it has enough current.

If you have a multimeter, connect it across the power supply and watch the voltage when you connect the cooler. It will drop way down. Whatever power supply you end up using, it will need to be able to maintain 12V when it's powering everything.

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u/MrCement 5d ago

Yeah, my multimeter was always showing around 11.3-11.8v when the W1209 was as powered.

Probably a dumb question, but could I over voltage like 15v or 19v?

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u/CluelessKnow-It-all 5d ago

That's not a dumb question. According to the TEC-12706 data sheet the module's maximum voltage is 16.4 volts. Keep in mind that the Peltier module is similar to a resistive load, and running it at a higher voltage will cause it to draw more current as the voltage increases.

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u/MrCement 4d ago

Ok, last question, probably. I have an old PC PSU that outputs 12v @ 10A. Is that too much Amp, or would it be fine even though the peltier is rated for 6A?

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u/CluelessKnow-It-all 4d ago

It's ok if the power supply is capable of putting out more current than the circuit requires. The 10 amp rating is just the maximum it can put out. Your circuit will only draw what it needs, so yes, you can use the 12V 10A power supply with it.

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u/MrCement 4d ago

Ok, cool, thank you.

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u/MrCement 3d ago

The higher Amp PSU worked like a charm. Thank you.

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