Im not understanding how combiner boxs are supposed to connect and work.

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nobody928
nobody928 Solar Expert Posts: 62 ✭✭✭✭
in Solar Beginners Corner #1
I would like to become more familiar with how the combiner boxs work. I see some for sale that have mc4 cables coming out of them. I have 4x 140 watt panels. My panels are 12v but I would like to wire them in series to get two banks of 24 volts. How many strings do I need inside the combiner box two or three? How do I install a combiner box? Any ideas that would work best for my application??


Thanks in advance
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Im not understanding how combiner boxs are supposed to connect and work.

    Combiner boxes are for making parallel connections between panels or strings of panels. They provide common connection points for all negative and positive leads, usually incorporating over-current protection on the positive side (i.e. circuit breakers).

    For two parallel strings only you don't really need one or even the current protection. In your case two panels will connect together in series directly to form a string, and then the same for the other string. These two strings would then be connected in parallel. This can be done with MC4 'Y' connectors, or direct to MC4 'pigtails' made from extension cables cut in half and spliced on to conventional wire for the down lead (must be watertight connection).

    If you are planning on future expansion, get the combiner box and wire for the total array size now as it saves having to change out wire later to accommodate increased current.
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