Peltier circuit Ideas

[abeledj]

Guys
Im trying to fix a peltier cooler. I have the temp control bad.
May I connect the peltier with a constant voltage and a switch ???
I tried to have it connected to 12 volts constant, but after like 30 seconds themperature on the cold side was getting higher ( it has 2 big Heatsink attached on each side) .. I don't want to burn the peltier module.
Thanks for any ideas !
Abel

 

[Mr RB]

Yes it is safe to use a fixed DC voltage. In your case it sounds like the voltage and current was too high, and there was too much heat for the size of your heatsink.

Remeber if you use a fan on the heatsink it will run a great deal better and be able to remove a lot more heat from the cooler.

 

[chemelec]

YOU DEFINATELY NEED A GOOD FAN on the HOT SIDE HEAT SINK.

If the Hot Side Gets too Hot, than there is No Cooling on the Cold Side.

But are you Sure you have your Battery Connect Correct Polarity.
Thermolectrolic Modules can work BOTH WAYS.

Doesn't seem Correct that the Cold Side is Heating up so QUICKLY.

 

[crutschow]

My understanding of a Peltier cooler is that the cooling is proportional to the average current but the power loss (heating) is proportional to the (RMS) current squared (due to the cooler resistance). Thus unfiltered PWM will be less efficient to control the power since the RMS current is higher than the average current. So, if you want to use PWM to control cooler power, you want to filter the PWM signal with an inductor so the average and RMS currents will be essential equal and the Peltier efficiency is maximized.