Please look over my solar diagram for Van RV

MysteriousFoundation
MysteriousFoundation Registered Users Posts: 31 ✭✭
I decided to go with 5x 175W panels instead of 4x, and I'm also not going to tilt them at first. This requires getting the TS-MPPT-60 and not the 45.

The layout and wire lengths in the diagram are not to scale. Everything it going to be as short as possible. Mostly under one foot per cable. All battery interconnect cables will be the same length. I might replace some of the smaller ANL fuses in the diagram with in-line breakers.

Any feedback is greatly appreciated!

https://i.imgur.com/NQaducV.png


Comments

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    The fues/breaker for the panels in series should be the maximum fuse size recommended on the reverse of the panels, typically 15A for that size, but if 20A that's fine, did you use the Morningstar string calculator http://string-calculator.morningstarcorp.com/ to make sure the configuration is good for local temperature extremes, worth a check. Use non automotive  breakers instead  of fuses, easy to trouble shoot more reliable and if blown can be turned back on. Otherwise the layout looks good.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • Dave
    Dave Registered Users Posts: 59 ✭✭
    I'm curious what your panels' max voltage rating is?
    12 * 300 W (10 fixed rooftop, 2 movable pole mount), Morningstar Tristar MPPT 60, Magnum 4448 PAE, 64 200Ah CALB in 4p16s arrangement with 16 LED Balancers and a Choice BMS300 (It is lousy and I don't recommend but it provides high and low voltage cutoff)
  • MysteriousFoundation
    MysteriousFoundation Registered Users Posts: 31 ✭✭
    edited July 2018 #4
    Yes, I used the MorningStar Calculator. That's the link with all the relevant values. I don't have the panels on hand yet, so I can't look at the back, and the spec sheet online doesn't appear to mention fusing. The Isc is 9.65A, and if I add 25% for unusual solar situations, then it comes to about 12A. A 15A fuse sounds appropriate. I'm not sure why I put down 20.

    What breakers do you recommend? Someone recommended MidNite Solar breakers and box in a previous thread, but it seemed like overkill to me for my RV. Is that along the lines of what you were thinking?

    I've been looking at the offerings from Blue Sea Systems. They're really pricey, and I wound need several of them. There are cheaper ones from random Chinese brands like ZOOKOTO. I don't know how reliable they are.

    I'm curious what your panels' max voltage rating is
    That's a very good question. It's something I never even considered. I guess I figured if the controller can handle the voltage then the panels themselves could, too. Wait, is that even what you're asking? How much voltage the panels themselves can take in series?

    I don't see the answer on the spec sheet on Amazon. Going to the company website doesn't show any more information. What's the typical limit for panels such as these?
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • MysteriousFoundation
    MysteriousFoundation Registered Users Posts: 31 ✭✭
    Is there any reason to believe these five panel wouldn't be able to handle upward of 90V when in series?

    Everything I can find about the voltage limit of panels comes down to the legal limit of 600V in some places, and the voltage limit of controllers. I can't find anything about the voltage limit of panels themselves. Considering the other limits I've found, I have a hard time believing there will be a problem, but please let me know if I should contact the manufacturer.
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    IMHO, 12v nominal panels aren't generally used in larger series strings, so I wouldn't count on them being designed for similar voltages as larger panels. They can probably handle 90v, but I'd check to be certain.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • MysteriousFoundation
    MysteriousFoundation Registered Users Posts: 31 ✭✭
    edited August 2018 #8
    The company finally got back to me. They said, "Normally about 10 175w panels can be wired in series.The voltage is about 100 volt."

    That doesn't make any sense to me. The panels have a Vmp of 19V. How can ten in series only be 100V? If she got the voltage wrong, but 10 in series is still safe, then that's good news for me. If she got the voltage right, then that's worrisome, because even with temps only as low as 60°F, the MorningStar calculator says five panels would yield up to 120V.


    I replied to ask for a clarification. We'll see what she says.

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    In General, you would wire up 5x Vmp~190 volt panels in series for 95 VDC Vmp-std (standard test conditions). And you would wire a second string in parallel for the other 5x panels (10 panels total).

    For 1-2 parallel strings, you do not need a separate fuse/breaker per string, but it can be nice for debugging (turn off array when working on system, turn off one string to see if the other is working correctly, etc.).

    How many panels in series and what size fuse/breaker to use--That is up to the vendor to tell you (and usually comes with UL/CSA/ETL "Listing". 15 Amp should be OK (need fuse/breaker rated for ~150 VDC)--20 amp is rated for some similar panels, and would have less of a chance at false tripping--If the 15 amp devices trip, then you may have to go to 20 amp devices--Although, many less expensive fuses/breaker have been known to trip at much less than rated current. The panels themselves, it is a guess. Voc-cold~150 VDC rated should be nominal for them--But they do not have to design for that (Voc-std is ~22 VDC per panel).

    Unless you live in a region where it gets way below freezing, the Voc-cold (voltage open circuit cold) should still be below ~140 VDC.

    If it does get well below freezing, then you have to check the Vpanel input of the solar charge controller is not lower than Voc-cold-array for your region.


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • MysteriousFoundation
    MysteriousFoundation Registered Users Posts: 31 ✭✭
    Thanks, BB.

    I just got a response from someone more knowledgeable:
    Our mistake with the voltages.

    Technically the maximum voltage is 600v, that's also the rating on the wire.  But to keep it safe i would say 500v will be an ideal number.

    Besides almost all the inverters dont need any voltage above 500v.

    For 5pcs in series, the voltage will be around 100v on open circuit, which is under the 150v allowance on Morningstar MPPT controller

    Perfect! Now I feel safe ordering everything.