My Batteries are not charging, please help

timoskytimosky Registered Users Posts: 2
Hello, I have a 120v battery bank along with 10 solar panels (I don’t know the ratings), a 3KVA inverter and a 60A 48v MPPT charge controller.
The batteries charge fine with normal electricity but do not charge with the solar panel. I’ve checked all the connections and everything seems fine. What else could be the problem???


  • mike95490mike95490 Solar Expert Posts: 9,571 ✭✭✭✭✭
    a 48v charge controller will be unable to recharge a 120v battery

    post more details please, models, Mfg's
    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

    gen: ,

  • timoskytimosky Registered Users Posts: 2
    edited April 2021 #3
    Thanks for the comment.
    The batteries are all VRLA 12v 150AH batteries, The charge controller is a Yohako 60A 12/24/36/48v charge controller. 

    Also, I read that more charge controllers may have to be cascaded to charge the batteries... how many of these charge controllers would I need??
  • BB.BB. Super Moderators, Administrators Posts: 32,601 admin
    How many 12 volt batteries do you have in series (10 batteries * 12 volts = 120 VDC battery bus).

    Yes, you can put a 60 volt charger on the "low numbered batteries" and 60 volt charger on the "high number" batteries in series... But not always that simple...

    First need to find a 60 VDC rated charger (in reality, need a charger that can output 75 volts or so)... Second, when you have chargers in series like that--Need to make sure that all wiring is protected by fuses, and the "high charger" output leads are rated for 60-150 VDC. Third, if you have any "digital or signal connections from charge controllers (alarms, status, etc.)--The offset in DC voltage can be a big issue too (i.e., your "ground reference is now (possible) 60 VDC for the "high string" charger.

    You need to be very careful with these high voltage/high current strings of batteries... The can be very dangerous (both from an electrocution and a fire point of view).

    There are (typically) UPS systems that are designed to work with 120 to even 340 VDC battery buses--But that is more often used in commercial/industrial installations.

    If your system is a 48 VDC battery bus (typical for home/small commercial systems), then we have to back up and get more information (typically 4x 12 volt batteries in series * X battery strings in parallel). And know more about your loads (WH per day) and charging needs (solar, genset, utilty power, etc.).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,804 ✭✭✭✭✭
    timosky said:
    I have a 120v battery bank 
    Are you sure? that would be unlikely as there are few 120v DC to AC inverters other than a few large UPS system.
    timosky said:
    "... 10 solar panels (I don’t know the ratings)..."
    You will  need to know the ratings of the panels to figure out the wiring for your charge controller...
    timosky said:
    "...a 60A 48v MPPT charge controller."
    We will need to know the parameters of the charge controller as well, so we can determine the proper wiring of your array. 
    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, 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.
  • MichaelKMichaelK Registered Users Posts: 224 ✭✭✭
    edited April 2021 #6
    Could you please take some pictures of your battery bank so we can see how it is wired?  Do you own a voltmeter?  What is the voltage of the battery bank in the evening after the sun has gone down?  What brand of inverter are you using?

    I've never heard of a single commercial retailer selling a 120VDC inverter.  This could be a 12VDC inverter putting out 120VAC that you are wiring incorrectly.  We need to know the inverter brand/model?
    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
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