Another fuse question

powersupplyguy
powersupplyguy Registered Users Posts: 3 ✭
in Advanced Solar Electric Technical Forum #1
What parameters should I consider when choosing fuses for panels?  I am running two strings of 4 panels.  Panel Voc is 32v and Isc is 8a.    I am thinking a small diameter Littlefuse 3AB 15A on each string.   They are rated 125vdc.  I will combine and use #10 into the battery bunker.  This OK?
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited October 2019 #2
    Circuit breakers would be a better choice IMHO, they allow switching of individual strings under load which is handy for testing purposes, they can be reset if tripped and  the end cost is about equal considering the fuse.holder along with some spare fuses.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • powersupplyguy
    powersupplyguy Registered Users Posts: 3 ✭
    #3
    Thank you mcgivor.  I will consider DC breakers
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #4
    Just make sure they are DC rated as well as being of greater voltage rating than voltage used. Also pay attention time polarity, some have a + terminal, this should be connected to the source of highest potential. The sponsor of this forum, NAWS, sells them click the store top left of this page, search DC circuit breaker, they sell quality items suitable for solar applications at reasonable prices with excellent service.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
    · Share on Twitter

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