Does anybody know of any good reason why even simple solar regulators are supposed to be connected so that they take their power from the battery under charge instead of from the solar panel itself?
One would think the solar panel should be the obvious choice since it eliminates the drain on the battery when it's raining or the RV is parked under cover.
Yes, the solar panel can go as high as 21 volts when open circuit but that seems to be within regulator voltage limits because I have connected a Solarex SC18 controller directly to the solar panel via a Schottky diode (with three other diodes charging and isolating three battery banks) and it has worked by fitting a resistor in parallel with the switch (negative switching).
Without that resistor it wouldn't work and I found that I needed to make a short across the contacts to initiate the charge so I started experimenting with resistors until I found the highest value that would still latch the regulator.
I'm no electronics engineer so if somebody who knows anything about this subject could explain to me why this shouldn't be done, or tell me of some other better way of achieving the same result I would really appreciate it.
