where do i need fuses?

bcolebuild
bcolebuild Registered Users Posts: 10 ✭
in Solar Beginners Corner #1
Hi everyone,

setting up my first off grid system, do i need any inline fuses between my

charge controller and batteries?
batteries and inverter?
batteries and my 12v lights or shurflow pump?

im pretty sure i should put a fuse between my bat and pump, how large should the fuses be and can i just use automotive equipment?

thanks
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: where do i need fuses?
    bcolebuild wrote: »
    Hi everyone,

    setting up my first off grid system, do i need any inline fuses between my

    charge controller and batteries?

    Yes.
    batteries and inverter?

    Yes.
    batteries and my 12v lights or shurflow pump?

    Yes.
    im pretty sure i should put a fuse between my bat and pump, how large should the fuses be and can i just use automotive equipment?

    thanks

    All you need is a 12VDC rated fuse of the appropriate Amperage for the pump. Since they don't draw much, there's probably a suitable automotive unit available. Not necessarily so for the charge controller-to-battery, and almost certainly not for the inverter. NAWS has these things available: http://store.solar-electric.com/cipr1.html

    In addition, if you have more than 2 panels in parallel you should have a fuse on each one.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #3
    Re: where do i need fuses?

    Look at it this way. Every piece of wire should be protected from over current between the current source and the load. Fuse(s) at the battery protect the loads powered by the battery.

    Life gets confusing in that in a PV circuit has a current source at both ends,, battery at one end and PV at the other. In simple terms, the wire should the be fuse at BOTH ends.

    Fuse sizes should always be considered relative to wire size, not load size. For example #14 wire should never be fused with fuse bigger than ~15 amps, regardless of voltage or expected load. (One should never load the wire bigger than it's fuse/current rating anyway)

    In short, there is never too many fuses (except for irksome nuisance tripping) So you can protect a wire with a 15 amp fuse at the battery say, then branch off to power a fan with a 3 amp fuse, and a radio with a 5 amp fuse etc.

    Hope this helps,

    Tony
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: where do i need fuses?

    One would hope the wire would be sized to handle the load first. :D
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #5
    Re: where do i need fuses?

    True,, but stranger things have happened!

    T
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