Adding panels to an existing system

[asdex]

Hi, i have 6 of these panels:JAM6 72-320. They are 72 cell. They are in 3 strings of 2 panels. Total 1920watt.
Could I add 4 of these panels facing a slightly different direction:
Model: JAM72S20 445/MR
Cell: Mono
No. of cells: 144(6×24)
Rated Maximum Power(Pmax): 445W
Maximum Efficiency: 21.2%

They would use the same cable and charge controller.
Thanks,

[Mike90250]

The voltage ( Vmp ) of each string (pair of panels) needs to all be the same spec for this to work well. If the strings are within 10% of each other, it will work just OK. The lowest voltage panels pull the whole array to their low voltage

[bcroe]

Since your original strings of 2 panels have 144 total cells (in series), one of
your new 144 cell panels could be tied directly in parallel. This single panel
"string" should then have nearly the same voltage rating as your earlier 2
panel strings, matched as Mike indicated.

More parallel panels can be added, if the rest of your system can handle the
additional current. The maximum operating current may be limited to less
than string totals, if different orientations are used for different strings. More
efficiency might be had in the wiring by doubling the number of panels (and
the voltage) in each string, half as many strings, if the system can handle it.
good luck, Bruce Roe

[solarix]

Don't obsess about solar panel efficiency. Solar PV panels are cheap now. What counts is dollars per watt. Usually, adding on larger, high-wattage panels is the cost effective thing to do (even if some of the wattage goes to waste because of mismatch to the old panels).

[asdex]

Yes maximum current on the controller is 15 amps and 150 volts. Im just going to check with the pump supplier on that 15amp. they say 6 x 275watt panels are needed. not sure if that can be achieved.