asking question in a different way

vidaliamanvidaliaman Registered Users Posts: 12 ✭✭
i own 2 55 watt systems, both with 7 amp controllers, 2 identical 12v RV batteries, can i simply hook both 12volt batteries (pos to pos, neg to neg), keep both controllers on each of their own batteries? would the controllers mess each other up?

thanks dave


  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    Wiring the batteries that way, the controllers would effectively be charging both. As long as the batteries are identical (and the same age and condition) that shouldn't be a problem.

    One thing to watch for is you want both controllers to see the same battery voltage, so wiring to the batteries should be as short, heavy, and equal as possible. If one controller sees a higher voltage than the other, it will leave the lower voltage one doing most or all of the charging.
    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
  • mvasmvas Registered Users Posts: 384 ✭✭✭
    Does your 7 Amp controller do an automatic / periodic Equalize Charge?
    Does the Equalize Charge, from each controller, need to be "synchronized"?
    What if the first Charge Controller Equalizes today, and then the second Charge Controller Equalizes tomorrow?
    Use a Manual Equalize?
    Equalize with only one controller?

    Before connecting the two batteries in parallel make sure both batteries are fully charged.
    Connect the Charge Controller and Loads using the "Opposite Diagonal" technique.

    Image result for opposite diagonal 12 volt battery connections
    The length of the Red wire and Black wire between the two batteries should be the same length.
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