I have 4 100w panels (WindyNation) wired in parallel to supply 12v to Victron Smartsolar 110/30 controller. If I rewire them to either series/parallel (24v) or straight series (48v) will I be able to still charge my 12v battery bank without any additional equipment? This will lower my voltage loss on my pv cable (12awg) as well, yes? Will it make a noticeable difference in being able to recharge my system w/ marginal (cloudy) skies?
You would not need any additional pieces. But check to make sure your specific panels are under 100 volts at the lowest temperature you will encounter with your system.
The best panel configuration will depend on many factors. Experimenting with 4 parallel, 2 series / 2 parallel and 4 series with simulated shade is worth the effort. For 24 volt configuration try 2 panels in parallel, then those in series and visa versa.
The voltage drop across the wiring from panels to the controller will depend on the length of course. E.g., 20 feet of 12 AWG with 4 panels in parallel will be about 1.6 volts or less than 10%. Half that number for 2s/2p. 25% for 4 in series. If you have long runs, you can also minimize voltage drop by running separate wires for each panel in parallel.
4 panels with a Voc of 21.6v - and the SmartSolar 100/30 is max 24v input so I guess series/parallel is my only option. We've been boondocking a year now and have rarely been forced to park where shade is a problem. Rain/clouds, now that's another story...
It's about 20 feet from panels to controller using 12AWG so I'll save .8 volts in transit 2s/2p?
Panel voltage goes UP as temperature goes DOWN. The 21.6 is at a nominal temperature so run the calculations at your minimum temperature.
Victron provides a handy calculator for such things:
https://www.victronenergy.com/mppt-calculator
Using one of Victron's 115 watt panels as an example, and 0 degrees F results in an open circuit voltage of 107.3 volts which is too high for the 100/30. Your milage may vary.
