Originally Posted by bob213
Herk, if you go with solar fans you will want to put a toggle switch inline so you can shut them off when your trailer sits in the sun while NOT being used.
I knew I was "over thinking" this.
I was trying to make it automatic using a feed from the "run" DC line to power a relay to feed an inverted output photocell to power on the solar fans.
First off, the solar fans won't run at night anyway!
Second, the relay will work (there are several cheap ones) but will increase battery drain by the amperage draw of the relay. (only a few milliamps buy I am trying to avoid battery drain at all.
A manual switch solves everything.
NASA invents the "Space Pen" at a cost of a million dollars.
Russia uses pencils.
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