I currently have a 100 watt solar panel, charging a 12 V, 6 Ah lead acid battery using a generic solar charge controller.

I am looking to connect a 12 V, 6 A Peltier unit, as well as a Raspberry Pi, to turn the Peltier on/off, during specific times.

I am currently running the Raspberry Pi Pico off this battery, using an LM7805 voltage regulator. I plan to use a IRFZ44N to control the Peltier device using PWM, to regulate it to a specific current ~3 A.

My main questions are around the power limitations, and if I will be able run the Peltier unit for the needed time (for example, 10 minutes every hour, through the night, ~1.5 hours.)

What is the optimal way to only draw 3 A from the battery to the Peltier, without losing too much power? Is the MOSFET the best solution? Maybe a switching-regulator to control the current draw, and MOSFET to control the power on/off?

  • \$\begingroup\$ See electronics.stackexchange.com/questions/515425/… \$\endgroup\$ Apr 4, 2022 at 17:34
  • \$\begingroup\$ Interesting question, however more information is needed. You have a 100 Watt Solar Panel, how many hours a day will you get 100W, 90W etc ie how much energy are you going to be able to collect. How many days without charging do you need. Replacing the 7805 with a buck converter will save some energy. I would also suggest you check the data on your peltier unit, many do not like PWM and fail prematurely when treated that way. \$\endgroup\$
    – Gil
    Apr 4, 2022 at 21:31


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