Solar in the shade
I mostly camp in wooded sites. Am I right in thinking that solar doesn't do much good in that case? My impression is that if part of the panel is shaded, the output of the whole panel drops pretty fas...
Forum Discussion
marcsbigfoot20b27 wrote:
If you have multiple 12v panels in parallel, they are actually 18-19 volts or so. Your non MPPT controller sets it at about 14 v to the batt at however many amps from panel size.
Shade just one panel and your voltage can drop to ~10 volts and you get almost no amps from the charger.
Now wire the panels in series and have ~60 volts or whatever your MTTP charge controller can handle......one panel is shaded and you end up with maybe 30 volts, but you are still over 14v which means you still get amps from a MPPT, in a nut shell.
Solar panels in parallel assume the same voltage and have their currents add.
So, if one gets completely shaded (0 amps) and the other two have full sun (max amps), then the current to the controller will be 2/3 of maximum current and at the same voltage as before - this assumes the panels have blocking diodes.
If the panels are in series and one panel is completely shaded, and if the panels have bypass diodes, then the current will stay the same, but the voltage will be diminished by 2/3's.
The series configuration becomes much more of an issue when bypass diodes are not used which effectively limits the current to an almost zero value.
