First, sorry if this has been answered, being a newbie one sometimes has to ask the obvious!
So I have a system I am building with twenty panels, each 310W so total array size of 6200W. From the Classic sizing chart if I enter ten panels the sizing chart says 1.2 units required, in the Note it says MidNite Solar recommends a second controller be added after 1.2. So does this mean I should really use two Classic 150's for each set of ten panels being four for all twenty, or can I squeeze one per ten panels of the above system meaning a total of two Classics?
As a second part to this question, whatever the configuration turns out to be do I connect the Classics battery outputs in parallel and to the whole battery bank - which is what I am assuming.
I am not an expert on this but the way I interpret the 1.2 is that you will never get full power from your solar array into the charge controller. You will loss power in the cabling and other factors such as heat at the array. If your charge controller is almost capable of handling the output is it worth the extra expense of a second one? Some people will install a second charge controller so they are not operating the one controller at max output. If money is of no concern go for a second controller. The output from your charge controller(s) should connect through a circuit breaker or fuse to your main cabling going to your battery bank.
Hi PaulC,
Welcome to the Forum,
Would definitely recommend that you use two Classic Charge Controllers (CCs) with that amount of PV.
There are several other variables -- Battery voltage (assume 48 V), String configuration -- number of PVs per string (assume two), and Specs on the PVs -- Vmp and Voc, at least.
You have been using the Classic Sizer, so you have entered Voc for the PVs, and assume that you are not at risk at very cold temps.
More later, Vic