The Vmp of your PVs is 39.8 V -- this is good, as it is high enough for the CCs to have enough voltage to find a good MPP operating point, and with strings of two PVs, the operating voltage is low enough for more efficient operation.
For anyone wondering about the NEC Max Isc, this is 8.50 amps which is about 6% over the NEC max with strings of two PVs with six strings per FM CC.
Your genset power leads seem fine, to me ...
Most Generac gesets that have a battery maintainer, look for the AC power on that line to be interrupted, as a genset Start command. So, just a relay that interrupts this AC line for the duration of the desired run time is often all that is required.
I have assumed that the FM60 CCs are already installed, otherwise it would not be a very big deal to swap them for FM-80s which have an NEC total PV Isc of 64 Amps, vs the FM-60's max of 48 Amps ... it that really matters to anyone.
Alan, approximately where is this system located -- what state?
I assume that this large system is Grid Interactive (Grid Tied with batteries).
Gotta run to town, more later, Thanks, Vic
Actually, im happy with the pair of fm60s. 24*315W*0.77/48V = 121 amps. The only reason to upgrade would be if youre trying to max out oppurtunity loads.
Well, personally, would not like to run CCs that flat out for hour after hour ...
This is probably a Grid Interactive system.
AND, if it is Grid-connected, it will probably need to be Inspected ...
So, then, probably, the NEC Maximum Isc rating of the PVs will apply ... in which case, FM-80 might have been a bit better ....
BUT, just my opinion. Vic