Hey guys, I’m new here and I’ve been working on a peltier based cooling system for my pet rabbits. Is it possible for me to use my Arduino Uno with my 12V 25 amp power supply to step down the amperage to 12 amps as a way to protect my 4, 3 amp peltiers but maintain the voltage at 12? If so, how would I go about doing that?
No, that is not possible. You can't control both the current and the voltage at the same time, and there is never a need to do so. Parts draw current, according to their characteristics, and the applied voltage.
You should drive the Peltier modules at the voltage they were designed for. Please post a link the product page or data sheet.
Interesting project. How do you intend on dissipating the heat from your Peltier device? Most of the heat is generated internally in the Peltier diodes.
So yeah...
Ohm's Law says Current = Voltage / Resistance. Or you can calculate that your Peltier devices are about 4 Ohms.
With nothing connected to the power supply the 12V is still there but no current flows.
If you connect a regular little LED with the proper current limiting resistor you'll get 10-20 mA. Without a current limiting resistor the LED will die quickly.
If you connect too many Peltier devices you'll draw excess current and the voltage will drop, and the power supply will shut down or burn-up or blow a fuse, etc.
I don't know that much about Peltier devices, but I believe they are non-linear... They have a resistance, but the resistance changes with the voltage and (I think) it goes down as the voltage increases so you can get more current than "calculated" from Ohm's Law.
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