I wired my 3 strings of panels in parallel, with each string feeding a 40A MPPT C.C. Would I get more charging power to my battery bank if I wired them in series, & fed them to a Magnum Energy PT-100 12V/24V/48V C.C.? I want to upgrade my battery bank with 6ea. Crown 6V 420Ah Batteries. Crown says I must provide 2.4 times panel wattage to Ah usage, to maintain the battery warranty. Currently, I have an 840W string(Vmp=17.8V;Voc=21.7V;Imp=7.87A;Isc=8.6A) & 2ea. 600W strings(Vmp=17.4V;Voc=21.V;Imp=5.75A;Isc=6.32A), for a total of 2040W. To achieve the 2.4 factor, I would have to add approx. 984W to my array, or 4 more 250W panels. The PT-100 specs. say it will accept input power of 6600W, & input voltage of 240V. To calculate total string voltage, do I use Vmp or Voc? Will I achieve better results with series-wired strings rather than parallel-wired strings? And why? Currently my inverter & battery bank is 12VDC. Would I do better with a 24V inverter & 24V battery bank? And why? I have a fairly short wire run of 40-50 ft. Also, would it be too much input power if I used 4ea. Canadian Solar 305W panels for my 4th string, instead of 4ea. 250W panels? Regards, from Richa.
