kjennejohn
New Member
Hi, DS.
Sounds like it's time to end the conjecture and actually test the enclosure for heat transfer capabilities.
Find a cheap meter that allows you to plug in a K-type thermal sensor. Some even come with the sensor. If not, buy a sensor recommended by the meter manufacturer. The meter may be a dedicated thermal device or a DMM with the plug and a thermistor selection on the selector dial.
Install a power plug on the enclosure. Seal all other openings and holes. Install a power resistor rated for 3 watts or better (you say the SBC is rated for 2.8W, max) across the power plug inside. This resistor must be a value such that the voltage you apply will make it dissipate 2.8W (or so). For instance, if you have a 12V supply handy, you can apply this across a 51 Ohm resistor (or multiple resistors to arrive at that value) to get around 2.77W.
Drop the K-type sensor (this usually looks like a tiny bead at the end of two wires in a funky sheath of insulation) into the enclosure. Install the enclosure top as best you can, trying to seal it tight without crimping the sensor wires. Plug the sensor's bladed plug into the meter. Now turn on the meter and power supply and watch the temperature rise. If it stops rising and stabilizes under the max temperature for the SBC, you're golden. If it rises higher than max, you're toast. Do this in the shade and in the sun.
Either way, you've settled the question and can get on with it.
kenjj
Sounds like it's time to end the conjecture and actually test the enclosure for heat transfer capabilities.
Find a cheap meter that allows you to plug in a K-type thermal sensor. Some even come with the sensor. If not, buy a sensor recommended by the meter manufacturer. The meter may be a dedicated thermal device or a DMM with the plug and a thermistor selection on the selector dial.
Install a power plug on the enclosure. Seal all other openings and holes. Install a power resistor rated for 3 watts or better (you say the SBC is rated for 2.8W, max) across the power plug inside. This resistor must be a value such that the voltage you apply will make it dissipate 2.8W (or so). For instance, if you have a 12V supply handy, you can apply this across a 51 Ohm resistor (or multiple resistors to arrive at that value) to get around 2.77W.
Drop the K-type sensor (this usually looks like a tiny bead at the end of two wires in a funky sheath of insulation) into the enclosure. Install the enclosure top as best you can, trying to seal it tight without crimping the sensor wires. Plug the sensor's bladed plug into the meter. Now turn on the meter and power supply and watch the temperature rise. If it stops rising and stabilizes under the max temperature for the SBC, you're golden. If it rises higher than max, you're toast. Do this in the shade and in the sun.
Either way, you've settled the question and can get on with it.
kenjj