-> CH> -> I use just two small panels- one on a tree trunk dedicated to
-> CH> -> and the other on the roof of the garden shed. Was surprised to
-> CH> -> "dark" current ie leakage out of the battery at night, was
-> CH> -> significant [I forget how many mA].
-> CH> ->
-> CH> -> Probably OK in summer, but not good for the winter period of l
-> CH> -> panel output.
-> CH> -> So I connected a permanent diode in a lead from each of the pa
-> CH> -> Problem solved.
->
-> Yep, standard procedure; many panels come with diodes prefitted, whic
-> suggest you remove if installing them in series, or by replacing with
-> blocking diode, if in parallel.
Ah.  I'd think there'd be a better way.  Maybe some light sensor and
power FET in series.  Those have a pretty low "on" resistance.
-> CH> But you lost the .7 volt drop across the diode in the process...
->
-> It's not usually relevant; most 12V panels have an open-circuit
-> voltage around 18-20V.  I've measured the difference in daylight
-> current with and without
-> diodes, and it's very slight indeed; anything lost (maybe 2-3W in hea
-> be more than saved by avoiding any reverse flow losses overnight.
-> Of course 'proper' regulators will suffer a diode or transistor drop
-> anyway.
Well, I'm generally never satisfied with less than 101% efficiency.

-c-
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