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Post by Jason on Nov 10, 2021 9:43:30 GMT -8
My system is going to have two loads applied to it as it runs: the 12v fan and the 5v RPi 3B+. In the scenario where there is a significant period of bad weather, is it safe to assume the fan will stop working once the battery voltage drops below 12v? And the RPi would stop working once the battery dropped below 5v?
Thanks,
Jason
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Post by SDL on Nov 11, 2021 15:30:27 GMT -8
SolarMAX2 will shut off the power to the Raspberry Pi, so that is covered.
Your fan? Depends on how it is hooked up. Tell me and I can look at the circuit.
BP
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Post by Jason on Nov 12, 2021 5:08:36 GMT -8
The fan is wired directly to the 12V OUT2 on the solar controller.
Thanks,
Jason
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Post by SDL on Nov 12, 2021 11:13:39 GMT -8
Looks to me like that 12V output is turned off may the over discharge circuitry (10.8V). That's pretty low and the fan takes a lot of current and will forestall the system turning back on until the system is turned up. But it protects you on the downside?
Have you thought of modifying the code to control the fan according to battery level and inside temperature? That would make a really good guest blog entry.
You can do that by wiring a GPIO line from the MiniProPlus to the OUT2 pins and modifying the C code.
BP
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Post by Jason on Nov 13, 2021 9:02:55 GMT -8
Hmmm…interesting idea! Lemme do some thinking and research and see if I can pull it off lol! I seem to do better with software than hardware 🤷♂️
Thanks,
Jason
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Post by Jason on Dec 11, 2021 4:00:28 GMT -8
After several days of low sunlight, the battery voltage has dropped below 12V and the fan is off. Definitely time to lower power consumption by the fan.  Thanks, Jason |
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Post by Jason on Feb 19, 2022 7:41:55 GMT -8
Still haven't spent any time looking into controlling the fan, however, I did disconnect it in order to see a before/after comparison on the overnight drain. Pretty noticeable dip!  Jason |
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Post by SDL on Feb 20, 2022 11:49:50 GMT -8
Jason,
Looks like your battery is pretty well charged during the day. Adding the control to the fan to work during the day should work pretty well according to your graphs.
BP
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