Multiple Charge controller

adeniyi609adeniyi609 Registered Users Posts: 1
Hi all. 

Please I need your advice.

I have one outback radian series 7KVA inverter and I plan to use 120 batteries to provide backup for 3 days for my system.
Here is the catch , I plan to go off grid or have less use of the grid so I have decided to get at least 6 flex max charge controllers to charge my battery bank. Please note its a 48Volt system meaning i should have 30 racks (4*30) =120. The batteries are 200AH each. Do you think above will work? I guess i will need a DC busbar.

Please if you can help me with a small diagram, I will be most grateful.


  • BB.BB. Super Moderators, Administrators Posts: 30,049 admin
    Can you tell us a bit more about your batteries that you will be using (i.e., 12 volt @ 200 AH?).

    And how you will be configuring your battery bank (4x 12 volt batteries in series, 30 parallel strings)?

    My first suggestion would be to select different batteries for the task (like high AH 2 volt cells) or other large capacity batteries (fork lift/traction/industrial batteries). Assuming you are going for a 48 volt @ 6,000 AH battery bank--That is a whole lot of energy and current capabilities if there is a short circuit.

    And if you are planning on 6x 80 amp Outback Flex mate controllers--That is only ~480 amps maximum current charging. If this is a full time off grid system with significant loads during the day--That may not be enough charging current to keep your battery bank "happy".

    I am reluctant to give specific information on a design, without understanding more about the application (what are your loads--day time, night time, 24 hours per day, etc.). How large of solar array, where will the system be installed. Backup genset? Seasonal usage patterns (you get less sun in rainy season, and have less solar power), etc.

    This is a very large solar power system--And you should be working with a Power Engineer who has experience with this type of system (and a history of successful installations). This is a big project for a first time designer/installer without help.

    Assuming you are in Nigeria or that region, you probably have limitations on (for example) battery cell choices.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonrjonr Solar Expert Posts: 1,360 ✭✭✭✭
    I agree, use 2V batteries.   And tell us how many KWH/day you need.  Possibly something like 3 parallel strings of L16RE-2V (3330 AH).

    I am available for custom hardware/firmware development

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