Conext MPPT 60 150 Array to close to max?

shawnj72

Hello, I am Just about ready to set up the Panels and wanted some feed back and if I am setting it up correctly.. Kind of a second look..

I am using ITEK 305w Panels 3 Modules in series and 5 Strings for a total of 15. Am I to close to max of the controller? and if I am what would be a better way. I live in the Upper Peninsula so it does get cold but the sun is low for those months. .looking for some feedback so i don't let the smoke out...

Power: 305 Watts
VOC (Open Circuit Voltage): 40 Volts
VMP (Maximum Power Point Voltage): 33.1 Volts
ISC: (Short Circuit Amperage) 9.8 Amps
IMP (Maximum Power Point Amperage): 9.1 Amps
VOC Temp Coef %: 0.29 C°
VMP Temp Coef %: 0.38 C°

Environmental Data
Coldest Ambient Temperature: -40 C°
Hottest Ambient Temperature: 90 C°
Nominal Battery Volts: 48 Volts

PV Array
Number Of Modules In Series: 3
Number Of Parallel Strings: 5
Total Modules 15
Rated PV Array Power: 4575 Watts
Anticipated Array Power @ 90C: 3445 Watts
Rated PV Array Current: 45.5 Amps
Battery Charging Current @ 57.6 V: 79.4 Amps
VMP (Maximum Power Point Voltage) : 99.3 Volts
VOC (Open Circuit Voltage): 120 Volts
VMP @ -40 C°: 123.9 Volts
VOC @ -40 C°: 142.5 Volts
Schneider Conext 60 150
Max Operating Voltage 140
Max Non operating VOC (HyperVOC) @ 48V Nominal Battery Voltage 150
Maximum Number Of Modules In Series 3
Max Number Of Modules In Series (Using HyperVOC)  5

Based On This Current Configuration 60 150 from the manual

"Each Conext MPPT Solar Charge Controller (solar charge controller) must be
connected to its own PV array. Although the solar charge controller can harvest a
maximum of 3500 W, the PV array size can be as high as 6720 W (based on
48 A × 140 Voc = 6720 W)."

BTW I am using Forklift Battery 24-85-15 900ah

Conext XW 6848 Inverter

Thanks for looking and  any feedback

Dave Angelini

Not bad work here. Some of your numbers that I looked at are sketchy. 
The bottom line is it will work and the mppt will be current limiting alot. Might be a good idea to plan a second mppt down the road.
Is this for offgrid? If so less of a problem now. In summer offgrid, you could just remove a string to lower the temp of the CC when in Bulk.

Estragon

IMHO, you should be ok.  Realistically, you likely won't see much more than 3500w (assuming U.P. is Michigan) anyway.  The extra panels will help get some charging on lightly overcast days, which I believe are fairly frequent there.

60a capacity into a 900ah battery bank is a bit on the low side for full time off-grid, but in your location I assume you're ready and willing to spark up a generator as needed.

The cold VOC margin is a bit skinny, but it seems to me we don't get really cold winters any more.  Something to be aware of though, so if it did get really cold you'd want to open PV in breaker the night before if a really cold low was forecast.

shawnj72

Thanks a bunch for the Reply.. Yes the UP Is Upper Peninsula of Michigan.. As far as overcast days I have seen where the sun leaves in late November and you wont see it till February. My plan is to Install another Array just like it in the spring with another controller so it should help but I do have a 10kw 13kw surge auto start gen to make up some of those overcast months :-) .... Im sure it will be a trial and error and learning curve but wanted to make sure i wasn't running the Controller to close to max .. thanks again from the Far Reaches of Michigan..

mike95490

Estragon said:

The cold VOC margin is a bit skinny, but it seems to me we don't get really cold winters any more.  Something to be aware of though, so if it did get really cold you'd want to open PV in breaker the night before if a really cold low was forecast.

I agree, very low margin on cold temps

shawnj72

My thoughts were I have the Conext 6848 and In the summer use as much as possible from the arrays and use the gen or a battery the  remainder of the night if needed . Im sure i can still pull from the grid if needed but still be more error and trial till i figure out the best way or solution to run it.. . I plan on another array and controller next spring as i heard you can never have too many panels.. especially  here as there are more grey days than sunny. I wasn't sure if I could configure out the array differently as i tried a number of different ways and it just didn't come out right.. I tried to cut it in half and make two but the numbers went way low or right high as i have them configured.. I guess I will keep an eye on it on the really sunny and cold days. I will be setting it up with a PLC to give status UPDATES and be able to monitor and control it from off sight also. I was planning on tracking the array because Engineer by Trade anything worth doing is worth Over doing is my motto.. I just want it just big enough to be self reliant and thought it would be a good project to go along with the Home automation Project.. 

Dave Angelini

The mppt-60 logs the cold temp voltage and you can read it on the display. You still have some headroom at low temps and I doubt you will get there with those numbers. Even if you did get alot colder, at this point it is a $500 dollar loss and reasonable, in my opinion.

Estragon

Really sunny and cold isn't so much the issue.  Even when it's really cold, the sun warms the panels quite a bit once it hits them. 

The problem would generally be around first light, when record lows are typically recorded.  There's just enough ambient light to get voltage up but not hitting panels directly yet.  That's why I suggested opening the pv in breaker the night before in the (probably unlikely) event really cold weather is expected.

Once the direct sun warms the panels, voltage would drop, and you could then start charging.

I'm north and west of you.  Record low here is -47°F, but we don't seem to get into the -40s much at all any more.

Dave Angelini

Sure, and that is why it is logged so that when you forget the disco, they forget warranty

Estragon

Maybe OP's home automation project will include a temp triggered auto-disco?

shawnj72

Thanks for the input , I’m sure I will have a lot of time making adjustments and logging foos and fonts and what works and what don’t. I have it tilt horizontally when the wind goes above 40 and vertically during snow accumulation. I have a couple 80 and 100a  12vdc coil and 24v coil contractors that would work for the disconnect . Lots to do yet before snow as it does come here quite early at times. Got behind a bit doing firewood and now a new septic so hopefully get back on track . And thanks again for the input and just wanted some input as if one might see another way I may do it different ... thanks again 

Dave Angelini

Since you asked again, I would have used the 80 amp 600V mppt. Much easier wiring 2 strings in a JB. Much easier to change things later and probably less loss/smaller wire if the distance is great. Either way you will be fine.