One 135w panel, cc, one 85ah batt - Fuse(s)?

MichaelJ
MichaelJ Registered Users Posts: 23 ✭✭
in Off Grid Solar & Battery Systems #1
Greetings,

Kyocera is rated 7.63a, Morningstar cc is 10a. My thinking is 10a fuse(s) between panel and cc. Do I also need fuse(s) between cc and battery? And yes, fuse(s) means I question fusing the positive only or both?

Also, am grounding the panel frame and battery negative terminal. Enough?

Thanks, Mike
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #2
    Re: One 135w panel, cc, one 85ah batt - Fuse(s)?

    Fuses protect the wire from current sources. You want to fuse at the battery as close as practible. A fuse from the cc to the (a single) PV is probably not essential, but certainly wouldn't hurt.

    You only need fuse the positive wire.


    Tony
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: One 135w panel, cc, one 85ah batt - Fuse(s)?

    Generally, for a single (or two parallel string) set of solar panels, you don't need any fuses.

    The only fuses/breakers you need is at the battery bank + terminal.

    Each fuse should be rated at 1.25x the maximum continuous current expected through each wire leaving the battery bank (one to charge controller, one to load, etc.).

    If you are going to fuse the Solar Panel (for three or more parallel strings, there is usually a series protection fuse listed in the data sheet... usually somewhere around 1.56x Isc.

    If this is a negative grounded system, normally you would not place any fuses/breakers in the return leads.

    Grounding the solar panel frame, typically to a ground rod or chassis of RV/Vehicle (depending on installation).

    Also, the negative battery lead should be tied to RV chassis and/or ground rod too.

    Grounding and fusing does get pretty complex with trade-offs in larger solar PV systems.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Slappy
    Slappy Solar Expert Posts: 251 ✭✭✭✭✭✭
    #4
    Re: One 135w panel, cc, one 85ah batt - Fuse(s)?

    but just to add a little. the system usually requires to hook battery first, then panel last, so use a switch or automotive blade type fuse between the CC and the panel so you can have a way to dis(connect) the panel with out pulling wire from CC. every time you need to do maintance on the system. But yes the 10 amp fuse is fine, I have the same panel and that is what I am using with no problems.
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  • MichaelJ
    MichaelJ Registered Users Posts: 23 ✭✭
    #5
    Re: One 135w panel, cc, one 85ah batt - Fuse(s)?

    Thank you for the replies, all were clear and helpful.

    Mike
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