Recommended operating temperature when running 24/7

[infertux]

I found that A20 chips support -25C to +85C according to https://www.olimex.com/forum/index.php?topic=2404.0 but I'd like to know what is the optimal working temperature range to maximize the lifespan of the board when it's running 24/7. I'm afraid things like capacitors or the DDR won't last many years if the board is always around +60C?

My A20-Lime2 stays around +36C for the PMU (cat /sys/power/axp_pmu/pmu/temp) and +46C for what I believe is the CPU (cat /sys/devices/virtual/thermal/thermal_zone0/temp). It's currently winter here so I expect it to get to +60C this summer.

Thanks a lot!

[MBR]

Generally, try to get the temerature as close to average room temperature (say, 20-25C) as possible, but never below the dew point (unless you have a hermetically sealed box with a dry air/moisture absorber). And use IR thermometer (or an IR thermal camera. if you have/can borrow one) for the measuring, because there may be hot spots too far from the board temperature sensors.

And yes, the electrolytic capacitors are the most temperature-sensitive parts, they degradation rate is directly proportional to functions of the temperature (the exact function depens on type), for the most common types, there is a rule of thumb called "10-degree-rule", where increase of temperature by 10C halves the lifetime. So try to keep them cool, but never under their minimum allowable temperature (they can freeze, which has dire consequences on the capacity and ESR).

[infertux]

Thank you very much. This is the kind of information I was looking for. The "10-degree-rule" is particularly interesting.

If anyone is considering putting the board into https://www.olimex.com/Products/OLinuXino/A10/A10-OLinuXino-LIME-BOX/, it raised the temperature by about 5 degrees for me but I think it's acceptable if it keeps dust and bugs from getting stuck into the connectors and GPIO pins.