Author Topic: Will this work?  (Read 324 times)

Saggys

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Will this work?
« on: February 27, 2022, 11:42:25 AM »
2 individual 6 panel arrays and 1-12 panel array for a total of 24-75 watt Siemens SP75 panels. These are already mounted and wired for my current 12 volt system, just have to reconfigure at the combiner box.

The SP75 specs: VOC 21.7, VMP 17, ISC 4.8, IMP 4.4

The longest run to the charge controller is about 20 feet.

The reason for the hi VOC required is I want to use all the panels on the 6 panel arrays, these are pole mounted, The other 12 panel array is a pole mounted Wattsun tracker. Plus, -20 degrees F happens every winter.

So 4 parallel strings of 6 panels in series with a VOC of 130.2 before adjustments for temperature and a VOC of 157.5 after adjustments, per NEC.

PV Array
Rated PV Array Power:   1800   Watts
Anticipated Array Power @ 98F:   1705   Watts
Rated PV Array Current:   17.6   Amps
Battery Charging Current @ 57.6 V:   31.3   Amps
VMP (Maximum Power Point Voltage) :   102   Volts
VOC (Open Circuit Voltage):   130.2   Volts
VMP @ -22 F°:   127.2   Volts
VOC @ -22 F°:   153.6   Volts
MNKID Selection
Max Operating Voltage   150
Max Non operating VOC (HyperVOC) @ 48V Nominal Battery Voltage   162
Maximum Number Of Modules In Series   5
Max Allowable Output Current Per KID
Based On This Current Configuration   30
Max Allowable Wattage Per KID
Based On This Current Configuration   1752
Present PV Array Wattage Of This Configuration   1800
Design Check
Max VOC   MARGINAL
(HyperVOC)
Temperature The KID Will
Enter HyperVOC   -5.8 F°
Array Power (Wattage)   EXCESSIVE
KIDs Required   1.1

Saggys

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Re: Will this work?
« Reply #1 on: March 02, 2022, 06:16:20 PM »
Do I need to move to a Classic 200 to handle the VOC?

ClassicCrazy

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Re: Will this work?
« Reply #2 on: March 02, 2022, 07:42:01 PM »
I wrote a different reply but looked at your post again.
Your string calculator report is for 5 pv in two strings so 10 panels.
But you say at the end of first post 4 parallel strings of 6 pv which would be 24 panels
So not sure what to comment unless you made a typo ?

Larry
« Last Edit: March 02, 2022, 07:44:03 PM by ClassicCrazy »
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , Jakiper 48v LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batteries

Saggys

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Re: Will this work?
« Reply #3 on: March 03, 2022, 06:33:57 PM »
It is 4 parallel strings, 6 panels in series. I am not sure if the sizing tool is suggesting I limit my series panels to 5 or I input the data wrong. I have checked it multiple times and it comes up with marginal for VOC and excessive for current, although slightly. I thought the controller could be slightly over paneled without causing any problems. I guess I am mainly concerned with the VOC, I need the controller to operate lower than -5.8 F.

mike90045

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Re: Will this work?
« Reply #4 on: March 03, 2022, 07:03:01 PM »
If you need the controller to function at -6F, then put that into the calculator and see what the Voc is .  as you approach the -22F, the classic would go into hyper mode and idle, till the Voc drops below 150V.
 at -22F, you are only a couple volts over the 150 limit, and with a bit of sun warming, that should drop below 150V , depending on ambient.   Maybe cold weather folks have more thoughts.
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV

mike90045

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Re: Will this work?
« Reply #5 on: March 03, 2022, 07:04:19 PM »
Does the Kid have hyper VOC ?
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV

Saggys

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Re: Will this work?
« Reply #6 on: March 03, 2022, 09:14:22 PM »
The Kid does have Hyper Voc. Good idea on using -6 degrees F with the sizing tool to see what  the VOC is. Thanks Mike.

Saggys

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Re: Will this work?
« Reply #7 on: March 03, 2022, 09:31:42 PM »
After messing around with the kid sizing tool, as soon as I enter -8 degrees F, the series string  number of panels goes from 6 to 5? I do not quite understand, must be from elevated VOC from the cold ambient temperatures. I really would like the Kid to work, but I need it to operate at colder temps, so maybe I need to look at the classic 200?