One array + 2 Chargers?

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fotodadi
fotodadi Registered Users Posts: 2
in Solar Beginners Corner #1
Hi all!!

So much info here...Well done guys!

I have a naughty problem and have been banging my head on how to solve it.

I have two battery banks with similar load connected...I am thinking of having a large array and connecting 2 chargers in parallel to the array so as to charge the 2 battery banks. My thinking is that if one bank gets drained faster and needs more charging, it will be able to have the full array at its disposal so that the charge time will be much shorter. Is this connection possible? Does anyone have any suggestions?

Thanks guts!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: One array + 2 Chargers?

    Welcome to the forum.

    You can't connect two charge controllers to one array. There are some charge controllers that can charge two batteries from one array. Example: http://www.solar-electric.com/modubachco25.html
    But it is dependent on the size of the batteries.

    Otherwise some of the more expensive MPPT controllers have an auxiliary function that can be used to switch in a second bank for charging, but this is complex and not easy to set up.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #3
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    Re: One array + 2 Chargers?

    If you are using PWM controllers, you can connect two controllers to one array (if the battery banks have a common ground connection)... there is even one smaller PWM controller that is designed to do this:

    wind-sun_2212_12349147SunSaver Dual Battery 25 Amp 12 Volt Solar Charge Controller


    It is used by RV folks to keep the house and vehicle batteries charged. Next time you need a new battery bank, use larger AmpHour batteries and have just one set to maintain.

    But from my point of view--if you have two systems with similar loads located in the same place--Why not combine the systems into one? This allows you to automatically manage power because the loads would be drawing from the same array/battery bank.

    Otherwise, you can find 12 volt to 12 volt battery chargers--and use the device to charge one bank from the other bank (and there are balancing type DC to DC converters that you can place between two battery banks).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
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    Re: One array + 2 Chargers?
    BB. wrote: »
    If you are using PWM controllers, you can connect two controllers to one array (if the battery banks have a common ground connection)... there is even one smaller PWM controller that is designed to do this:

    Uh, Bill; that's two batteries to one controller. Not two controllers to one array.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #5
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    Re: One array + 2 Chargers?
    a large array and connecting 2 chargers in parallel to the array so as to charge the 2 battery banks
    Marc,

    I may have misunderstood the question (not the first time)... See what the OP needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • fotodadi
    fotodadi Registered Users Posts: 2
    #6
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    Re: One array + 2 Chargers?

    Thank you so much for your feedback, guys!

    Have to plan for a second array then.
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #7
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    Re: One array + 2 Chargers?
    Cariboocoot wrote: »
    You can't connect two charge controllers to one array...

    Actually, that is quite common to do so in order to keep two or more battery banks charged up from one panel or array. The only catch is that both controllers have to be rated to handle the full panel amps, because if one battery is fully charged all the current can go to the 2nd one.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #8
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    Re: One array + 2 Chargers?

    Okay I should have said you probably shouldn't connect one array to two PWM controllers.
    And you really shouldn't connect one array to two MPPT controllers.

    My original statement is simpler and keeps the newbie from making mistakes either way. :cool:
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