Do I need PV breaker to charge controller if my panels connected in series

SkinnyCow
SkinnyCow Registered Users Posts: 10 ✭
in Solar Beginners Corner #1
I plan to have 3 Grape panels at 100w each connected in series down to the Rogue MPT-3048 charge controller. The Rogue manual states that I need PV breaker on the positive wire to solar panel. It doesn't say what kind of panel's connectivity is. I thought that I only needed PV breaker if I connected my panels in parallel. Is this correct?

If I do need PV breaker for series connection, can you recommend me one? Each Grape panel floating voltage is 21.5v so serial connection would be 64.5v. The controller can handle up to 100v.

In addition, is it safe to connect in series or parallel? I'm worried about sending too much voltage down but my cables are over 30ft so I want to increase the voltage instead of current. Could you explain the advantage/disadvantage of parallel vs series? I understood the basic so I want a more real life experience with both connections.

Thanks in advance.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Do I need PV breaker to charge controller if my panels connected in series

    You do not need a breaker when there are no parallel connections of PV.
    Voltage has no effect of circuit breakers or fuses, other than the need to be able to interrupt that Voltage.
    There will be <6 Amps of current on that circuit.

    If you were to put all panels in parallel then each should have its own fuse or breaker. The rating would be 10 Amps. You would also need to use at least 6 AWG wire for 30 (combined current being over 15 Amps and Voltage quite low).

    Rogue probably recommends a breaker as a useful disconnect, but even with the input shorted there should never be an over-current condition.

    One down side to running a high Voltage array is the reduced controller efficiency. I don't know how well the Rogue will handle this.
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  • TucsonAZ
    TucsonAZ Solar Expert Posts: 139 ✭✭
    #3
    Re: Do I need PV breaker to charge controller if my panels connected in series

    I did DC breakers to function as a disconnect, I would suggest doing the same but it isn't a must have, just a good idea to be able to turn off or disconnect panels when needed.

    As for voltage, higher voltage is fine, better with a long run like that but I tried to keep bank voltage and voltage to CC one step off, so 24v in to 12v bank, 48v-24v, 72v-48 and so on. Just a good idea but you could do 72v to a 12v bank if you really wanted also.

    Good choice on the Rogue cc!
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