Flexmax 60

waynec5waynec5 Registered Users Posts: 5 ✭✭
in Caravan, Recreational Vehicle, and Marine Power Systems #1
Hi, my flexmax 60 constantly displays "low light" after tracking at any time of the day. I have a single 12v 190ah deep cycle battery at the moment with no load connected. The battery reads 12.5v and I can't get the controller to go into charge mode. Help please. 
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  • PhotowhitPhotowhit Solar Expert Posts: 5,998 ✭✭✭✭✭
    #2
    What type of solar panels do you have and how are they configured?
    Solar panels watts, VMP and IMP?
    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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  • waynec5waynec5 Registered Users Posts: 5 ✭✭
    #3
    2x 200w tenesol in parallel. 
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  • waynec5waynec5 Registered Users Posts: 5 ✭✭
    #4
    Vmp is 27.1v and imp is 7.9 
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  • waynec5waynec5 Registered Users Posts: 5 ✭✭
    #5
    Voltage in on the display reads 28.1 
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  • PhotowhitPhotowhit Solar Expert Posts: 5,998 ✭✭✭✭✭
    #6
    waynec5 said:
    Voltage in on the display reads 28.1 
    I don't use the Flexmax, but suspect the charge controller believes you are trying to charge a 24 or higher voltage battery. 

    Check how this is set on the charge controller, It might be a sensing thing, where the battery must be connected first, or just user settable through the display or DIP switches. Check your manual.
    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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  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #7
    What is the required PV voltage the FlexMax needs to activate the MPPT ?  If your panels don't meet that spec - - - - - -
    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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  • BB.BB. Super Moderators, Administrators Posts: 33,327 admin
    #8
    Generally, the minimum is something like 2-3 volts Vpanel input higher than Vbatt output (15 volt battery charging -> 17+ Volt input).

    Remember that a "typical" 12 volt solar panel has Vmp~17.5 volts -- But that is with cell temperature at ~77F/25C... At operational temperature under full sun on a hot/sunny/windless day, that Vmp-panel can fall by almost 20%. (17.5*0.8=14 Volts Vmp--Roughly).

    Vmp curves are not that sharp of a peak, so 5% off of Vmp, is still pretty close to full power.

    Here is an older post with graphs showing Vmp vs Imp vs Pmp vs Temperature:

    https://forum.solar-electric.com/discussion/5458/two-strings-in-parallel-with-unequal-string-voltages

    Note--One graph is for Vmp~35 volt panel... For Vmp~17.5 volt panel, simply divide the voltages by 2...

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