Mix And Match Solar Panels

bloodofheroesbloodofheroes Registered Users Posts: 22 ✭✭
Just wondering if these two panels will play well together in a parallel system. I am planning to do five of the 250w panels and one of the 330w. Advice?



Comments

  • littleharbor2littleharbor2 Solar Expert Posts: 704 ✭✭✭✭
    Different voltages wont play well. These are two very different panels, one being 60 cells and the other 72 cells. The amperages are closer together so they would series wire a little better though the lower amperage will dictate output. Neither option is optimum.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • bloodofheroesbloodofheroes Registered Users Posts: 22 ✭✭
    So are you saying to flat dont do it? What happens if I do?
  • PhotowhitPhotowhit Solar Expert Posts: 4,280 ✭✭✭✭
    I always thought that in series, it would just bring the voltage of the higher voltage panel down to the same as the lower voltage panel. But there is a discussion around here somewhere where (I think) @BB. said it would hunt more for the maximum power point.

    I'm assuming you intend to use these with a MPPT type charge controller? The 5 are not a compatible voltage for charging through a PWM charge controller.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • mike95490mike95490 Solar Expert Posts: 7,307 ✭✭✭✭
    The panels are not a match for parallel connection,  Your 330W panels will be pulled down to the voltage of the 250V panels.

    In series, they are much more closely matched, and could work, if their voltage is below the controllers max input.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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  • bloodofheroesbloodofheroes Registered Users Posts: 22 ✭✭
    mike95490 said:
    The panels are not a match for parallel connection,  Your 330W panels will be pulled down to the voltage of the 250V panels.

    Not "330w panels." Only one 330w panel.

  • HorseflyHorsefly Registered Users Posts: 268 ✭✭✭
    edited December 6 #7
    The general rule is that if you want dissimilar panels to work in parallel, their Vmp voltages need to be within about 5% of each other. Similarly, to run dissimilar panels in series you need their Imp currents to be within about 5%. 

    In your case the voltages are too far apart to run them in parallel, almost 20%. The lower voltage panels will drag down the voltage of the higher voltage panel.

    As @mike95490 said, running them in SERIES isn't quite within 5%, but would probably be OK. The current through the string would be limited by the current of the lower Imp panels (the Boviet), which would limit the Suniva panel to 8.3A instead of 8.8A  at Imp. This would make it a 311W panel instead of a 330W panel, but that isn't too bad.
    Off-grid cabin: 6 x Canadian Solar CSK-280M PV panels, Schneider XW-MPPT60-150 Charge Controller, Schneider CSW4024 Inverter/Charger, Schneider SCP, 4 x Vmax XTR12-155 12V, 155AH batteries in a 2x2 24V 310AH bank.
  • softdownsoftdown Solar Expert Posts: 1,558 ✭✭✭✭
    My understanding is that the higher output panels will basically match the lower output panels when used together. I like to keep things simple. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 150 watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • bloodofheroesbloodofheroes Registered Users Posts: 22 ✭✭
    Horsefly said:
    The general rule is that if you want dissimilar panels to work in parallel, their Vmp voltages need to be within about 5% of each other. Similarly, to run dissimilar panels in series you need their Imp currents to be within about 5%. 

    In your case the voltages are too far apart to run them in parallel, almost 20%. The lower voltage panels will drag down the voltage of the higher voltage panel.

    As @mike95490 said, running them in parallel isn't quite within 5%, but would probably be OK. The current through the string would be limited by the current of the lower Imp panels (the Boviet), which would limit the Suniva panel to 8.3A instead of 3.8A  at Imp. This would make it a 311W panel instead of a 330W panel, but that isn't too bad.
    Thats kind of what I was wondering. Just dont want to do damage to the panel. I can live with it running at the current that the rest of them are running.
  • EstragonEstragon Registered Users Posts: 1,616 ✭✭✭✭
    As you may already know, you'll need to fuse/breaker each panel to avoid a short in one panel being fed by current from the other five.
    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
  • HorseflyHorsefly Registered Users Posts: 268 ✭✭✭
    Note that I was in too much of a hurry when I typed my reply above. I've fixed it, but the key thing is you can run your panels in SERIES, but I wouldn't run them in parallel.  Sorry for my error.

    Do what I meant, not what I said.   :)
    Off-grid cabin: 6 x Canadian Solar CSK-280M PV panels, Schneider XW-MPPT60-150 Charge Controller, Schneider CSW4024 Inverter/Charger, Schneider SCP, 4 x Vmax XTR12-155 12V, 155AH batteries in a 2x2 24V 310AH bank.
  • bloodofheroesbloodofheroes Registered Users Posts: 22 ✭✭
    Estragon said:
    As you may already know, you'll need to fuse/breaker each panel to avoid a short in one panel being fed by current from the other five.
    What kind of fuses do you recommend?? Keep it cheap. Its a small system. I am just doing this for a R/V.
  • PhotowhitPhotowhit Solar Expert Posts: 4,280 ✭✭✭✭
    What kind type and kind of charge controller will you use? What system voltage will you use?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • bloodofheroesbloodofheroes Registered Users Posts: 22 ✭✭
    edited December 7 #14
    Photowhit said:
    What kind type and kind of charge controller will you use? What system voltage will you use?
    I dont have a charge controller. Its grid tied. I use more energy than the panels provide. The system is 24v
  • EstragonEstragon Registered Users Posts: 1,616 ✭✭✭✭
    > @bloodofheroes said:
    > Estragon said:
    >
    >
    > As you may already know, you'll need to fuse/breaker each panel to avoid a short in one panel being fed by current from the other five.
    >
    >
    >
    >
    > What kind of fuses do you recommend?? Keep it cheap. Its a small system. I am just doing this for a R/V.

    MNTS holders w/15a fuses, about $8ea for holder + fuse from our host. Personally, I'd use MNEPV breakers @~$11ea.
    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
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