Solar setup

Torontoman
Torontoman Registered Users Posts: 1 ✭
edited March 2017 in Solar Beginners Corner #1
Hello forum. I am currently in the process of creating a solar setup for my off grid property and have read alot about fuses and/or breakers for the system. I have 24volt panels, (3x280 watt), as well as a 12/24 volt 80 amp charge controller. 4 Trojan 6 volt 150T deep cycle golf cart batteries. I'd like to install fuses on each panel before the controller as well as before the battery bank and maybe even before the inverter, (1000 Watt pure sine wave). My delema  really is what size fuses do I need to use or how would I figure that out? Thanks for any help on this
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
    I highly recommend you consider breakers instead of fuses. They don't cost much more than proper fuses and holders, and are much more convenient for use as disconnects.

    You need them (positive side) on each panel, between the inverter and batteries, and between charge controller and batteries. None are optional. Wire and breaker/fuse sizes recommendations and wire sizes should be given in your inverter and controller manuals.
    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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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    edited March 2017 #3
    T-man,  we will need the panel specs to start answering your questions...as well as the brand/model controller you plan on using... and the system voltage..
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    edited March 2017 #4
    Torontoman said:
    Hello forum. I am currently in the process of creating a solar setup for my off grid property and have read alot about fuses and/or breakers for the system. I have 24volt panels, (3x280 watt), as well as a 12/24 volt 80 amp charge controller. 4 Trojan 6 volt 150T deep cycle golf cart batteries. I'd like to install fuses on each panel before the controller as well as before the battery bank and maybe even before the inverter, (1000 Watt pure sine wave). My delema  really is what size fuses do I need to use or how would I figure that out? Thanks for any help on this
    You have a couple things going on, WestBranch is trying to get more info to ascertain. I didn't know of any 80 amp PWM charge controllers. I did a quick search and came up with one a SolarEpic. Is this what you have? if so what is the VMP of your 280 watt panels? The reason we ask is that if it's a 60 cell design, it will have too low a VMP for charging 24 volt battery bank, something around 30 volts is too low for a PWM charge controller. It might and perhaps 50:50 be a 72 cell panel and have a vmp of around 35 volts.

    The reason we are getting ahead of our selves is if you have a MPPT type charge controller and 60 cell panels, the only way to use all 3 effectively is as a single string (if combined VOC isn't too high), if you have a single string you really don't need a fuse/breaker but a breaker ahead of the charge controller is always nice.

    For fuse or breaker sizing, the info is often on the back of the panel, most use a 15 amp fuse/breaker. If you can't find a fuse rating you can often look for a pdf file online with information about your panels. If you use a single string, be aware the fuse/breaker is current specific so a single string of 3 panels will require the same fuse/breaker as a single panel as the current remains the same (only the voltage increases)
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #5
    Photowhit - Good point. OP didn't specify 24v inverter, but it stands to reason it's a 24v system. If fusing each panel, that implies parallel and PWM controller. Need more info.
    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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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #6
    Estragon said:
    Photowhit - Good point. OP didn't specify 24v inverter, but it stands to reason it's a 24v system. If fusing each panel, that implies parallel and PWM controller. Need more info.

    He very well could have a 12 volt system, I actually hadn't thought about that, with a 1000 watt inverter it's a definite possibility. If he has a 12/24volt charge controller that is a PWM type he has even more issues, mostly a lot of waste.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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