STMN250 needs to be RSS compliant...parts needed to make it so

Started by Beyla, March 04, 2019, 01:31:04 PM

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Beyla

Greeting and may the sun shine brightly,

I have an STMN250 e-panel, I want to make it RSS compliant. Will replacing the 250A breaker with a 250A Remote Trip Breaker be all I need or is there more parts needed to make it compliant? Thank you in advance for responding. Thank you and let the sunshine in.

P.S. what kind of birdhouse do I require to provide confirmation feedback at the birdhouse of inverter shutdown via remote trip, I heard there were two types.
Classic 150, DiscoCombiner4X 6 circuit(MNPV6HV 4X), 10 panels @ 2600 Watts, MS4024 Inverter, 8XCrown 6 volt batteries in 24Vbank. Epanel 250Amps/ w remote breaker and Birdhouse.WhizBang Jr., BTS.

FNG

Not sure of that model number but based on your signature I am assuming you have the MNE250STM?

First, step is to tell us what you have for PV and combiners and charge controllers as in order to be rapid shut down compliant you need to shut off the pv array.

Second, step would be IF you want to shut down the Magnum we would use the following:

MNBIRDHOUSE1-RED or -GREY
MNBDM to control the breaker
MNEDC250RT
And if no combiners you need the MNFX-CABLE

These can all be found here"http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=44&productCatName=RAPID-SHUTDOWN-SYSTEM-NEC-690.12"


Beyla

PV array size just below 2600 watts 4 strings of 3 panels, Classic 150, MS4024 inverter, standard MNPV6 combiner with 6 x15 amp breakers but no RSS, this is what I have... also, 8 x6 volt batteries rated for 220 ah for 20 hours. I need birdhouse, e-panel, remote trip 250amp breaker for inverter shutoff, MNDBM and an RSS capable Disco Combiner. Help....
Classic 150, DiscoCombiner4X 6 circuit(MNPV6HV 4X), 10 panels @ 2600 Watts, MS4024 Inverter, 8XCrown 6 volt batteries in 24Vbank. Epanel 250Amps/ w remote breaker and Birdhouse.WhizBang Jr., BTS.

FNG

So with 4 strings, you need the following:

MNBIRDHOUSE1-RED or -GREY
MNBDM to control the breaker
MNEDC250RT remote trip breaker
MNPV4HV-DISCO 3R-DLX-PSB combiner
MNCAT5-600 cable to go from combiner to birdhouse to E-Panel

I am assuming you have the E-Panel already as you stated you did in the first post?

Beyla

Thank you very much, yes I have the epanel. One more question, if I may. I have 3x230watts, 3x250watts solar panels. I need to stay below the 2700 Watt Max for the Classic 150 at 24volt Battery bank. What is my best options for string configuration and the fact that I would prefer a total of 8 or 10 panels instead of 12, given my existing panels and Battery bank size of 8x6volt 220ah(20 hrs) ?

For example could I use 2strings of 3 and 2 strings of two to get my wattage within tolerance of Max PowerPoint ? How many KWhrs can I store in that bank per day? Any advantages or disadvantages , my latitude is Ottawa Canada so I don’t get equatorial stuff up here, hehe.. thanks. Right now this gives me a total of 1540 Watts, thank you again.
Classic 150, DiscoCombiner4X 6 circuit(MNPV6HV 4X), 10 panels @ 2600 Watts, MS4024 Inverter, 8XCrown 6 volt batteries in 24Vbank. Epanel 250Amps/ w remote breaker and Birdhouse.WhizBang Jr., BTS.

Vic

Quote from: Beyla on March 05, 2019, 02:50:25 PM
Thank you very much, yes I have the epanel. One more question, if I may. I have 3x230watts, 3x250watts solar panels. I need to stay below the 2700 Watt Max for the Classic 150 at 24volt Battery bank. What is my best options for string configuration and the fact that I would prefer a total of 8 or 10 panels instead of 12, given my existing panels and Battery bank size of 8x6volt 220ah(20 hrs) ?

For example could I use 2strings of 3 and 2 strings of two to get my wattage within tolerance of Max PowerPoint ? How many KWhrs can I store in that bank per day? Any advantages or disadvantages , my latitude is Ottawa Canada so I don’t get equatorial stuff up here, hehe.. thanks. Right now this gives me a total of 1540 Watts, thank you again.

Hello Beyla,

When connecting PV modules in parallel,   the STC  (Rated) string  voltage should match within 10 % maximum variation,   and ideally,  be within 5%.

You will not get very good performance at all when trying to connect some strings that have about 90 V STC String voltage with ones with a string voltage of about 62-ish volts,   assuming 60-Cell PVs for the above voltage guesses.  Essentially,   the power from the strings of two PVs would be lost.  Two Charge Controllers (CCs),  could be used,  one with strings of three,   and the other with strings of two.

Getting a good match on the string voltage is much more important than trying to get the exact maximum total PV power to match the recommended Maximum from the Classic String Sizer.    It is often OK to oversize the PV array somewhat,   but not excessively so on the MidNite CCs

Also,  you might have a bit of trouble finding new 230 watt PVs,   and perhaps also with the 250 that you were considering.  Perhaps you have some of the PVs already.


Strings of two would be about ideal for a Classic 150,   on a 24 V Flooded battery bank.

FWIW,   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Beyla

Thanks Vic,

Yes, I can still get the 250w panels. One last question, if I have 4 strings of 3 panels and shade a portion of my panels equally on all strings, so that I get a max of 2500 Watts and rotate the shade on a yearly basis, would that be acceptable? I can calculate by area.
Classic 150, DiscoCombiner4X 6 circuit(MNPV6HV 4X), 10 panels @ 2600 Watts, MS4024 Inverter, 8XCrown 6 volt batteries in 24Vbank. Epanel 250Amps/ w remote breaker and Birdhouse.WhizBang Jr., BTS.

Vic

Hi Beyla,

Again,  would not be too concerned about a bit excessive PV array on a Classic.   Particularly,  if  you are not using relatively high PV input voltage to the Classic 150.

Just used a random 250 W Poly PV,   and ran it through the Classic String Sizer:

Rated PV Array Power:  3000 Watts
Anticipated Array Power @ 40C:  2798 Watts
Rated PV Array Current:  32.8 Amps
Battery Charging Current @ 28.8 V:  104.2 Amps
VMP (Maximum Power Point Voltage) :  91.5 Volts
VOC (Open Circuit Voltage):  113.4 Volts
VMP @ -30 C°:  114 Volts
VOC @ -30 C°:  134.1 Volts
 
Classic, Classic SL & Classic Lite Charge Controller Selection
150   
Max Operating Voltage  150 
Max Non operating VOC (HyperVOC) @ 24V Nominal Battery Voltage 174
Maximum Number Of Modules In Series 3
Max Number Of Modules In Series (Using HyperVOC)  3
Max Allowable Output Current Per Classic
Based On This Current Configuration  91
Max Allowable Wattage Per Classic
Based On This Current Configuration  2611
Present PV Array Wattage Of This Configuration  3000
  Design Check 
Max VOC  OK
Temperature The Classic Will
Enter HyperVOC  -73 C°
Array Power (Wattage)  EXCESSIVE
Classics Required  1.2

NOTE: MidNite Solar recommends a second controller be added after 1.2
NOTE: Generally speaking you'll want to use the Classic 150 or 200 as they are less expensive and will handle more power. With MPPT controllers the higher the input voltage the less efficient they are. This is not a large value but it will add up to a little more heat in the controller and a point or two less in efficiency. BUT you also have to be careful not to have the input voltage to low. Most all MPPT controllers will want to see a minimum of 130% of the actual high battery voltage. So if we have a 48v battery and it has an Equalize voltage if 62.3 volts than we would multiply that by 130% and we would need a minimum of 81 volts on the input on the hottest day of the year in order to have enough headroom for the MPPT to work.
WARNING: MidNite Solar makes no representation, warranty or assumption of liability regarding the use of the String Calculator. This tool uses data provided by other parties (such as PV module specs) and makes calculations based on assumptions which may or may not prove to be valid.
To ensure proper start up and MPPT operation, the minimum initial PV input voltage should be at least 30% higher than the highest expected battery voltage. "

  Beyla,   you should run the actual PVs that you plan to use through the sizer.

Really,  you would be better off using six strings of two PVs.   This will reduce the Vin to the CC,   at the small cost of needing two more breakers in the Combiner,   and two added PV cable runs to the Combiner,   IMO.

The Classic will Limit its output current,   and should run safely with your 12 250 W PVs,   particularly if your use six stings of two PVs.   If the CC will be in a HOT environment,   then perhaps 12 PVs will be a bit excessive  ...

Below is the pdf,   which is easier to read,   but,   the above has Footnotes.

More later,   FWIW,   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Vic

Hi Beyla,

In looking at your previous Posts,   it looks like your 250 W PVs may be Canadian Solar.  Ran the Classic String Sizer for the CS 250s that you had previously linked to,   and got the Attached results for six strings of two of these.

The 6X2 configuration should allow the CC to run a bit cooler,   and since you already have the Magnum 24 V inverter,   seems that you will not be going to 48 V anytime soon.

And,  from that Link to the CS PVs,  changed the temperature limits for a location, 
EDIT,   but now see that you are in Canada   ...  so those temperatures in the SIzer are probably far too high for the coldest temp entry ...  the risks of too much guessing.

FWIW,   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Beyla

Thanks, Took me awhile to reply, had so much to digest and check out. Thank you all for the great references and time you spent educating me on this part of the project. I’m getting there, slowly but surely. My next step is to ask the Electrical Solar Safety Authority if all is well in Solar Heaven.
Classic 150, DiscoCombiner4X 6 circuit(MNPV6HV 4X), 10 panels @ 2600 Watts, MS4024 Inverter, 8XCrown 6 volt batteries in 24Vbank. Epanel 250Amps/ w remote breaker and Birdhouse.WhizBang Jr., BTS.