Fuse/breaker sizing

Hi everyone. I just pieced a small system together and need help on fuse or breaker sizes.  I purchased a hightec 200w panel. This will be fed into my 20a Mppt controller. The controller will go to a 100ah group 31 agm battery. The battery will go to a blue sea systems 12 panel blade fuse box which will be wired to my vent fan, USB hub, sockets and overhead led lights. Where do I need fuses and what size. Other than the panel and brackets, this is what I have ordered so far. Anything else I need? Thanks 


1. Battery 100ah
7. Smart battery isolator https://www.amazon.com/dp/B00WTAFR84/ref=cm_sw_r_cp_apa_i_uZt9Cb3MKA1E6

Miscellaneous wiring, hardware and sealant

Comments

  • EstragonEstragon Registered Users Posts: 4,478 ✭✭✭✭✭
    I'd put a DC rated breaker between the controller and battery.  Size depends on wire, but I'd use the largest wire that physically fits on the CC output terminals, and size the breaker to whatever the controller maker recommends.

    I'd also put a breaker on the wire going to the fuse panel, again sized to the wire.  Fuses could be used, but breakers make handy disconnects.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Petes67birdPetes67bird Registered Users Posts: 4
    Estragon said:
    I'd put a DC rated breaker between the controller and battery.  Size depends on wire, but I'd use the largest wire that physically fits on the CC output terminals, and size the breaker to whatever the controller maker recommends.

    I'd also put a breaker on the wire going to the fuse panel, again sized to the wire.  Fuses could be used, but breakers make handy disconnects.
    Could you link me to breakers that you would use that aren't too spendy? Thanks for the advice
  • EstragonEstragon Registered Users Posts: 4,478 ✭✭✭✭✭
    These are pretty reasonable:
    https://www.solar-electric.com/mnepv.html

    A box to mount them.  There's also a bigger version which might be useful if you want buss bars / more room for connections:

    https://www.solar-electric.com/baby-box.html
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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