Hi Folks,
I have started making plans to build a small, efficient and quiet campervan fridge. I'm going to use very high quality insulation, thick insulation, so that I don't need to do too much cooling.
I actually started this project last year, but have not thought about it in a few months, so have forgotten a few things and need some advice.
My general approach is to use an Arduino R3 to sense the temperature in the fridge using a thermocouple, then send a PWM signal to the Peltier modules to bring the current down to the required amount to cool/maintain temperature.
As the system powering the modules is a 12v leisure batteyr, I have bought two TEC1-12709 16v, 9a, 90w modules. My plan is to run them underpowered to maintain efficiency. My understanding is that they don't like PWM due to I^2R losses, so I was planning on putting an LC low-pass filter in. This i where I'm getting a bit lost. A few other threads have said to also in a diode, creating a DC-Buck converter - however, are DC-buck converters not normally for stepping down voltage?
I'm planning on using a logic level mosfet (TIP120 suitable?) to switch the +12v supply. I'm a total circuit/control newbie, so any advice, even if it's a pointer on where to go and learn the basics would be great.
My initial power-switch circuit is attached. I'll worry about the temp sensing part later.
I have started making plans to build a small, efficient and quiet campervan fridge. I'm going to use very high quality insulation, thick insulation, so that I don't need to do too much cooling.
I actually started this project last year, but have not thought about it in a few months, so have forgotten a few things and need some advice.
My general approach is to use an Arduino R3 to sense the temperature in the fridge using a thermocouple, then send a PWM signal to the Peltier modules to bring the current down to the required amount to cool/maintain temperature.
As the system powering the modules is a 12v leisure batteyr, I have bought two TEC1-12709 16v, 9a, 90w modules. My plan is to run them underpowered to maintain efficiency. My understanding is that they don't like PWM due to I^2R losses, so I was planning on putting an LC low-pass filter in. This i where I'm getting a bit lost. A few other threads have said to also in a diode, creating a DC-Buck converter - however, are DC-buck converters not normally for stepping down voltage?
I'm planning on using a logic level mosfet (TIP120 suitable?) to switch the +12v supply. I'm a total circuit/control newbie, so any advice, even if it's a pointer on where to go and learn the basics would be great.
My initial power-switch circuit is attached. I'll worry about the temp sensing part later.
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