Hello all, hope you're doing well.
I have a peltier (12 V and 7 Amps) and I want to control its temperature using Arduino. I was using the N channel dual MOSFET module and it worked just fine except that it does not switch polarities.

I have read about H bridges but still not sure and it is better to ask about that any professional or experienced engineer. Are there any modules to directly use with my application or should I build it myself?

Thanks.

 

This should work. Read the documentation. https://www.makerfabs.com/h-bridge-motor-shield.html

 

A relay DPDT is workable too.

 

This should work. Read the documentation. https://www.makerfabs.com/h-bridge-motor-shield.html

This will be enough to use alone right? No need to use the dual MOSFET module and a relay.

 

A relay DPDT is workable too.

That's great, how would the signal be sent to this relay? I believe it has NO and NC switches right? If there is flow of voltage then, the one switch will close to change polarity, and if no voltage flowing then will return to the normal position. So actually I will still need the dual MOSFET module inorder to be connected with the arduino, and using the module, we will control the flow of voltage to the relay to determine the polarity. Is that right?

 

Just wire up the relay like an H-bridge to reverse the polarity, use a simple NPN transistor to control the relay coil and a NFET to switch the main power to ground.
then you have just 2 signals: ON/OFF and HEAT/COOL.


Here is a hot tip: switch the relay only when the power is OFF and the relay will live almost forever.

 

Just wire up the relay like an H-bridge to reverse the polarity, use a simple NPN transistor to control the relay coil and a NFET to switch the main power to ground.
then you have just 2 signals: ON/OFF and HEAT/COOL.


Here is a hot tip: switch the relay only when the power is OFF and the relay will live almost forever.

Thanks for the reply and for the tips.

This is my drawing using 2 SPDT relays (SRU-06VDC-SL-C labelling 10A 30VDC) and a peltier (12V and 7Amps). I know that like this the arduino will burn out,you said to add a transistor and an NFET. Can you please put them in the drawing so I don't make a mistake? Thanks a lot!!

 

Here is a quick sketch.

You need to chose a NFET that turns on fully with whatever voltage the Arduino puts out when HI.
A garden variety NPN transistor will be fine assuming the relay coil is low current, or just use another NFET in it's place.