Wiring mixed panels for radios

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cris
cris Registered Users, Users Awaiting Email Confirmation Posts: 4 ✭
in PV Installers Forum - NEC, Wiring, Installation #1
Hi,
I am installing 2 radios for internet in a off grid situation. The radios are Ubiquity Powerbeam M5 400 and each require  24V, 0.5A Gigabit PoE and Max. Power Consumption 8W. 
I have 3 Solartech 85 W, 12 V. , 5.15 A panels and 1 Sharp 80W, 12V, 4.7 A panel.
To get 24 V I need to connect 2 panels in series.  I would also like to connect 2 in parallel to maximize Amp.  Can I do that?  What would it be the best wiring for this system?  
I also have several 40A, 12 V batteries.  I am thinking to make a bank of 2 in parallel and 2 in series.  Would this work and be sufficient for this system?  I live in sunny central and California with at least 6 hr/day of sun in the winter. 
I imagine I need to get a controller for 24 V.  (I have a morning star for 12 V but imagine it won't work, right?)
Thank you,
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #2
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    First, you might check to see that the radios can handle the voltage range of unregulated 24 volt system, roughly 23-30 volts.

    2 strings of 2 solar panels would work fine, you will lose a tiny bit with the 85 and 80 in series. And the 2x2 battery bank should also be fine assuming the batteries are all the same type and capacity. They system is also reasonably well balance, the 4 panels should put out about 10 amps at 24 volts normally with a peak of about 13 amps on cold winter days or about 12.5% charge rate normally.

    Some Morningstar charge controller can be used either as 12 or 24v. Not sure what you have, it may be as simple as hooking up to your battery bank first, and some may have a dip switch or electronic interface.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • cris
    cris Registered Users, Users Awaiting Email Confirmation Posts: 4 ✭
    #3
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    Thanks Photowhit.  I read that the radios need a constant 24V.  I am hoping the controller will do this?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #4
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    Here is a company that makes DC to DC for POE powered systems:

    http://tyconsystems.com/index.php/dc-passive

    Otherwise, contact your Ubiquity re-seller and see what they recommend... I could not find any detailed specifications.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #5
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    cris said:
    Thanks Photowhit.  I read that the radios need a constant 24V.  I am hoping the controller will do this?
    The Charge controller supplies power to charge the batteries.  It is not a stable voltage, when the battery is low, you see 23V, while the battery is approaching full charge, it can be 28-30VDC.
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #6
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    You might find a variable 12v input to stable 24v POE injector easier to find (mobile/marine markets) than 24->24v. You would also be able to use the 12v controller.
    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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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #7
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    See post #4 above for wide range dc input to fixed dc output poe supplies.

    - Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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