20V to 5V regulator overheating?

Hello - I’m attempting to power a RPi 4B from a 20V drill battery.

I purchased D36V28F5 from Pololu and it certainly works - but after ~30 minutes of power connected & the RPi in an idle state running no code I’m reading temperatures in excess of 130 F.

I’m new to spec’ing step-down DC voltage regulators and would love Pololus technical direction here.

  • Should I purchase a buck with different characteristics (higher amperage rating?) or am I overlooking something else here?
  • Is this temperature performance uncharacteristic for the product I purchased?

Thanks much!


I am not sure how you are measuring the regulator’s temperature, but if the chip’s surface temperature is 130°F, that is nothing to be worried about. The regulator IC on the D36V28F5 has a recommended operating temperature range up to about 255°F, and its over-temperature shutdown typically kicks in around 300°F.

However, Raspberry Pis can draw more current than that regulator is rated to handle depending on what you are doing, so depending on your future plans, it might not be a bad idea to consider one of our more powerful regulators, like our D36V50F5.

- Patrick