I recently opened the farmbot’s control panel box when I was confused by the temperature the farmbot was reading and the ambient temperature of the greenhouse- It was showing the temperature of the Pi to be around 70 degrees C when it was 12 degrees C in the greenhouse. Confusing, right?
Well, I opened the door and was greeted by a blast of warm air. What in the hell? Are the electronics giving off so much heat that it doesn’t cool correctly? I’ve negated the concern by just leaving the panel door open, but really, should I grab the CAD file for the electronics box door, quickly add some vents and a hole for a RasPi fan, and then print it out? Or should I leave it? The place I am at is freezing in the winter and blazing a million degrees in the summer. You guys tell me what you think.
Frequency Management and Thermal Control
All Raspberry Pi models perform a degree of thermal management to avoid
overheating under heavy load. The SoCs have an internal temperature sensor,
which software on the GPU polls to ensure that temperatures do not exceed
a predefined limit; this is 85°C on all models.
It is possible to set this to a lower value, but not to a higher one.
As the device approaches the limit, various frequencies and sometimes
voltages used on the chip (ARM, GPU) are reduced.
This reduces the amount of heat generated, keeping the temperature
under control.
Personal preference is to positively ventilate the electronics box, esp with ambient above 30’C
I also have mine in a greenhouse with the same temperatures as yours. I have a 6" cooling fan aimed at the resting position going off at 90 degrees F. Being in a greenhouse, I also remove the door during the warmer months in the summer. Its been running for over 3 years now with no problems. I had though about mounting a few small fans on the side of the case, but haven’t seemed necessary yet.