Charge Controllers in Parallel

LoboLobo Registered Users Posts: 18
I keep seeing that like controllers, such as the Morningstar TS-60 can be run in parallel to charge a single bank of batteries. How is this accomplished with the wiring? Are both Controller outputs wired to buss bars and then to the battery bank?

Thanks

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,698 admin
    Re: Charge Controllers in Parallel

    As long as the charge controller's do not supply too much current (typically not more than ~13% of the battery's AH rating, or less than 25% if there is thermal management for the battery bank)--It is not a problem.

    My recommendation is to run dedicated wiring from the battery (or battery bus bars) through a fuse/breaker to each charge controller ("star" wiring). If you daisy chain the wiring (from battery to controller A to controller B, etc.), the electrical noise from one controller can confuse the 2nd controller.

    The two charge controllers will most likely not remain "synchronized" (they will shift from bulk to absorb to float at somewhat different times) but that is not a problem. The charge controller with the "highest" set point will "win".

    It can get a bit more complex if you have solar and wind (shunt or diversion type) charge controllers on one battery bank. But it is very common to have multiple charge controllers on one battery bank.

    -Bill

    PS: I should add, there are some higher end charge controllers that will "syncronize" charging states with external databus connections.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: Charge Controllers in Parallel

    Exactly. Morningstar says in their literature that it's fine to parallel their charge controllers. I have two Prostar 30M controllers, and one Morningstar 10L. Each has a separate bank of solar panels, and the output of all three are connected to the battery bank via a common set of bus bars. They each regulate as expected, no worries of one backfeeding another.
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: Charge Controllers in Parallel

    A few pictures of the 3 charge controllers working together. Total charging current is 48.6 Amps. The clamp on ammeter was used on all 3 charge controller input lines at once. The first 30M charge controller is supplying 23.7 Amps, the second one 17.1 Amps. The 10L controller doesn't have a display, but subtracting the other two from the total, it's supplying 7.8 Amps.

    3-chargers-1.jpg

    dscn6257.jpg

    dscn6258.jpg

    dscn6259.jpg
  • LoboLobo Registered Users Posts: 18
    Re: Charge Controllers in Parallel

    Robert, thanks for those pictures. Do the leads from the charge controllers in that system run to bus bars? If not, how are they tied together to the batteries?

    Thanks again
    2manytoyz wrote: »
    A few pictures of the 3 charge controllers working together. Total charging current is 48.6 Amps. The clamp on ammeter was used on all 3 charge controller input lines at once. The first 30M charge controller is supplying 23.7 Amps, the second one 17.1 Amps. The 10L controller doesn't have a display, but subtracting the other two from the total, it's supplying 7.8 Amps.

    3-chargers-1.jpg

    dscn6257.jpg

    dscn6258.jpg

    dscn6259.jpg
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: Charge Controllers in Parallel

    Yes, I'm using bus bars.

    buss2904.jpg

    buss2902.jpg

    hangerbolts.jpg

    P/Ns and sources of materials at this link (halfway down the page): http://2manytoyz.com/battbank.html
  • LoboLobo Registered Users Posts: 18
    Re: Charge Controllers in Parallel

    Robert ... Thank you for posting these pictures! I have 1200 watts of panels and two charge controllers (Morningstar Tristar 60). Will be using the L16's in the bank.
  • louielouielouielouie Registered Users Posts: 18
    Re: Charge Controllers in Parallel

    this is off topic for this thread, but BB answered a question earlier that i have been trying to find an answer to about parallel wiring controllers.
    thanks.
    my question is a connection question.
    can you connect, piggy back, the battery charging cable to the same post as the battery cable going to the inverter?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Charge Controllers in Parallel
    louielouie wrote: »
    this is off topic for this thread, but BB answered a question earlier that i have been trying to find an answer to about parallel wiring controllers.
    thanks.
    my question is a connection question.
    can you connect, piggy back, the battery charging cable to the same post as the battery cable going to the inverter?

    Yes. In fact it is the usual method for single battery/string. It is also a description of connections made to bus bars or common points. The only difference is in having one size fuse for the controller and another for the inverter.
  • louielouielouielouie Registered Users Posts: 18
    Re: Charge Controllers in Parallel

    thanks cariboo.
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