Hi everyone,

I've been reading many forum posts and articles about MOSFETS and reading their datasheets.
Although I'm getting more comfortable with the topic, I still have a lot of questions.

As I'm running out of time due to a timeline on my project, I decided to ask for help and see if what I'm doing makes any sense or is even feasible.

So, the project is a water cooler, that will be used in wine making to keep the wine fermenting at around 18ºC to 20ºC.
The quantity of wine is low that will be using the cooler btw.

To achieve this, I've bought 4 x 12706 TECs, essentially 60W Peltier's.
I've measured one of them and at 12V it pulled around 4 to 4.5A depending on the temperature diferencial between the hot and cold side.
I'm powering all of this with a 38A at 12V Server Power Supply.
I will be controlling everything with an Arduino Nano that will be reading temperature sensors.
At last, I've also purchased 3 IRL1004 MOSFETS, which are rated to 130A max and have a low VGS(th) value of only 1V.

My plan was to use 2 of these, where each MOSFET controls 2 TECs, which pull max 10A.
I will also have a 100ohm resistor on the gate, to stop having a current spike on the Arduino when turning on the MOSFET.

I have the following questions:
1 - Can these MOSFETs drive 10 to 20A continuously at 12V? I mean without using PWM, just as a switch.
2 - Can I have the MOSFET with a source of 12V and the Gate at 5v? Will it fully engate on this state?
3 - How can I know the peak current draw of the MOSFET when applying a voltage to the Gate? Lets use the IRL1004 for example, with a RDS(on) of 0.009 ohms at 5V driving 20A.

Thank you for your time and help on this.

Best regards,
Ralms.

 

hi Ralms,
Welcome to AAC.
For such high continuous Drain currents, I would consider using an intermediate Gate driver that switches 12V to the N MOSFET Gate.
Using 12V for Vgs will open up a wider range of options for selecting a power MOSFET.
E

 

hi Ralms,
Welcome to AAC.
For such high continuous Drain currents, I would consider using an intermediate Gate driver that switches 12V to the N MOSFET Gate.
Using 12V for Vgs will open up a wider range of options for selecting a power MOSFET.
E

Does that mean that the answer for my second question is a no?

 

Thermoelectric modules are very inefficient at cooling compared with conventional refrigeration. If your room is already too warm, a couple hundred watts is going to make it even hotter. Think about ducting the waste heat outdoors. Or buy a real mini fridge and use a heat exchanger and circulating pump to feed a cooling jacket around the fermentation vessel. Your MOSFETs could control the pump motor.

 

Thermoelectric modules are very inefficient at cooling compared with conventional refrigeration. If your room is already too warm, a couple hundred watts is going to make it even hotter. Think about ducting the waste heat outdoors. Or buy a real mini fridge and use a heat exchanger and circulating pump to feed a cooling jacket around the fermentation vessel. Your MOSFETs could control the pump motor.

Yeah I was testing them right now connected directly to the PSU.
The amount of heat this thing produces is insane.
I knew it was gonna be warm, but not this warm.

And the cooling capacity is less then I was hopping for, currently circulating like 6L of water and it took 20mins to lower 2ºC.

The mini-fridge was one option, but we decided to go with these TECs first as it was cheaper.

 

The hot side of the TEC must be attached to biggest heatsink you can use and for achieving lower temperatures in cold side, heat from hotside heatsink must be removed as much as possible using ventilator or other cooling equipment. The current flowing through TEC is proportional to temperature difference between hot and cold side, that means if hotside temperature raises then coldside temp raises too in practically same amont, if TEC current is constant.