Matching Panel Configuration to Controllers

StevenB

I am building my system in increments....ground mounted...and because of the space available, by necessity laid out in a single row (90 linear feet). My current intent is to add one small group at a time, 200 watt REC panels. I've already got my Xantrex 6048 Hybrid, battery bank (16 100amphr @48v), one turbine, and for pretty much just the learning process..........2) 60 watt Kaneka panels with a small controller.

So I want to add a XW-MPPT60-150 Controller to handle the staged additional groups of REC 220 panels (the Kanekas to remain but run as is, on it's own current controller). Btw...we've already buried a lot of conduit and marked location of each projected group of panels to run the wiring without digging ditches up a million times

So here (finally?) is my question:
I have been told that I can add up to 3 REC 220's in series. And I assume group 3's in parallel. Below I've included the specs for the controller and panel.
1) What in this info tells me that I can run upto 3 panels in series?
2) What in this and taking in consideration the Xantrex 6048 let's me know how many panels total I can run off this controller?
3) What hardware do I need to combine multiple groups of three series panels in in parallel (if parallel is the correct assumption) ?

REC
Module SCM-220
Peak Power 220
Peak Power Voltage 28.3
Peak Power Current 7.6
Open Circuit Voltage 36.4
Short Circuit Current 8.2
Max. System Voltage 1000
Series Fuse Rating 12



XW-MPPT60-150 Controller
Electrical Specifications
Nominal battery voltage 12, 24, 36, 48, 60 Vdc
Maximum PV array voltage (operating) 140 Vdc
Maximum PV array open circuit voltage 150 Vdc
Array short-circuit current 60 Adc maximum
Maximum and minimum wire size in conduit #6 AWG to #14 AWG
Total power consumption while operating 2.5 W (tare)
Charger regulation method: Three-stage (bulk, absorption, float)
Two-stage (bulk, absorption)

BB.

Re: Matching Panel Configuration to Controllers

Xantrex has a nice sizing tool for their XW MPPT solar charge controller.

From their tool, 3 panels per string is the only acceptable configuration for your 48 volt battery bank. You have to add panels in strings of three panels each for a maximum a 5 strings and 3,300 watts of solar panels.

To combine strings--you can purchase boxes that have internal breakers or fuses, or make your own. Once you go past two parallel strings, you will need to add a fuse/breaker that is rated for the recommended series protection fuse for that solar panel (for the 220 watt panel, that fuse should be around 15 amps--the fuse should be defined in the REC specifications).

-Bill

StevenB

Re: Matching Panel Configuration to Controllers

OH BOY, that's a nice resource.
When putting the first set of 3 up....what foresight might be useful, knowing there will be another 4 sets added? Would it be useful to hookup the first set to a combiner box right from the start, to simplify the adding of the next set?
And I am assuming a combiner box is not an outside component, mounted in the battery barn with the rest of the stuff?

Thanks!
Steven

BB.

Re: Matching Panel Configuration to Controllers

The combiner box should be able to mount outside in a sheltered area (protect from direct rain and sun).

Where you mount it depends on you... You can mount the combiner box out at the array (short runs of small awg wire to the panel, then one run of large awg wire to the controller). Or you can mount the combiner next to the charge controller (long runs of smaller awg wire to combiner, one short run of large awg to the charge controller).

The first will be more expenses up front (long run of large awg wire). The second may require more work (multiple pulls / conduit) of small awg cable).

You do not need a combiner/breaker/fuses until you exceed two parallel string connections.

Planning ahead will probably tell you what will work best for you.

-Bill