Two MPPTs, two pv arrays, two battery banks, but one combined output?

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fordperf
fordperf Registered Users Posts: 2 ✭
in Solar Beginners Corner #1
I'm new but, picture a system of 16 pv panels, eight 6v batteries, two mppts we'll call them A and B.

Each mppt has 8 panels and 4 batts in series for 24v. The output of each mppt is 24vdc.

Normally with two output rails, devices are either wired and powered by A, or wired and powered by B. If A or B goes down, anything wired to it is dead.

Is there a way to wire the outputs of A and B together, maintaining 24vdc, and connecting all devices to the common rail.. knowing that the rail doesnt have enough power to run all the devices at once, but other management tools would turn on/off devices, allowing all devices to operate even if A *or* B were to go down?
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  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    #2
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    Usually, there would be only one 24V battery bank... 

    In your case, both series strings of four 6V batteries would be connected in parallel to make a larger 24V bank. 

    Then, both A and B  controllers would contribute as needed.


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  • fordperf
    fordperf Registered Users Posts: 2 ✭
    edited February 2020 #3
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    In my noobness I failed to understand the system correctly, but I am learning.

    I understand now that the battery bank would be two strings of (6V x 4) in parallel, AND that the bank would be connected to BOTH charge controllers. That was my design misunderstanding #1.

    I learned I would not be powering the loads using the "output" of either controller, but instead would have loads connected directly to the battery bank plus and minus rail. Thus there is no need to combine anything, I simply run the system off the batteries, rather than off the controllers. The controllers worry about sharing the charging duties. That was my design misunderstanding #2.

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