Breaker Box

GloriaGloria Registered Users Posts: 3
I am just starting to set up my off grid solar power. I am starting with a 400watt system to see where and when I need the most power. I will run a water pump, television, laptop and small mini fridge. The only thing running daily is the fridge. I have wired outlets throughout the cabin in case I later want to add additional appliances. My question is what type of circuit breaker box do I need. I have a 1500w inverter that I will be using and probably 4 12v deep cycle batteries. My heat, cooking and hot water will be propane.

Thanks for your feedback:)

Comments

  • mvasmvas Registered Users Posts: 384 ✭✭✭
    edited May 2017 #2
    What do mean by "what type of circuit breaker box".

    12.5 Amps = 1500 Watts / 120 Volts 
    You have an inverter that is barely big enough to supply the fridge OR the water pump.
    You need to specify the amps needed for each load.
    You need to figure out how many CB's you need and what size (in amps) ...
    1) Fridge
    2) Water Pump
    3)Television & Laptop
    4) Everything else ?

    Do you understand this diagram?
    https://www.homepower.com/sites/default/files/articles/ajax/docs/7_HP136_pg78_Munro-5.jpg
  • littleharbor2littleharbor2 Solar Expert Posts: 1,628 ✭✭✭✭
    Does your inverter have hard wire terminals? Pure sine wave?

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 540 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    what is the make , model of your fridge and its age....  year of manufacture is important...  and location.

    As far as the 400watts of PV you will need up to 1600W to regenerate your batteries and to run the fridge and other loads during the day. In the summer I can run the fridge and Net connection  while I am away on ~1200W but when in residence I need the additional ~500W for incidentals. Winter is a whole different issue.
     
    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
  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    A couple of thoughts:
    1. You will need a second source of power for cloudy days. Even a small fridge will take a fair bit of power and 400w might just be enough to charge on really nice summer days. That being the case, you may want to use a small generator interlock panel. It will have a pair of breakers and a lockout so you can select either inverter or generator power, but never connect both at the same time. It will also have room for maybe a dozen breakers for branch circuits, which are typically wired with 14ga wire and 15a breakers.
    2. Using 4 x 12v batteries can be a problem (assuming 12v dc system), as it can be difficult to balance load and charge current with more than a couple of parallel strings. 4 x 6v golf cart batteries wired as 2 x 12v strings would be a better choice. In any case, be sure to get deep cycle type batteries. 12v automotive starting batteries won't last long if cycled deeply.
    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
  • GloriaGloria Registered Users Posts: 3
    Thanks for all the info. :)
    1. I will have a generator as backup and additional power. The inverter is pure sine and hard wire.
    2. The batteries will be deep cycle and the fridge is brand new 4.3 energy star. 
    The interlock for the generator is something I was also curious about as living in Michigan I can forsee the need to use it frequently. The battery size is something else I wasn't sure about. I know to get deep cycle but not sure how many and what size. The system will be increased along with the batteries and inverter. I have used 14g for all the outlets and lights and 12 for a possible washer/dryer hookup later on. The washer/dryer will always be used with the generator..but thats a year or so from now. I am questioning if there is a specific type of breaker box I need for this system? Or can I use a standard 100amp box with two 20amp breakers and 4 15amp breakers?
  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    The thing with using a standard panel is it would be possible for both the inverter and generator source circuits to be live at the same time. A lockout panel has a metal plate that allows only one of the source breakers to be on. The orange box store sells a square D generator panel for about $100. There also panels with automatic transfer switches that sell for several hundred.

    Some hardwired inverters have a built-in transfer switch. If yours has this, you would wire the generator output to the inverter ac in, and the inverter will pass through the generator output. In that case, you could use a standard AC panel. If the dryer is 240v, you may not be able to use the inverter bypass though, and you would need to make sure the inverter transfer switch and wire is sized to handle generator current.

    6v golf cart batteries are normally available at box stores for abot $100each. A set of 4 would give you about 450ah at 12v. Your fridge will likely use around 1.5kwh/day, or ~150ah with system losses. For a full-time occupied cabin, we'd normally suggest more like 800w of pv to support loads and charge batteries, but you'll just need to run the generator more. A good way to do this effeciently would be to run the generator for an hour or two in the morning to get the batteries charged to ~75%, and let the solar finish charging.
    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
  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited May 2017 #8
    If you are in the position of planning it is best to start with basic loads, then build to suit, don't fall into the trap of building too small, only to realize later the need to add PV and battery capacity, it is a costly mistake. A 400w array is unlikely to support a refrigerator as the only load, there is a need to charge the battery as well. Get yourself  a Kill-a-watt device and measure all your loads over a 24 hour period to establish a base line, add them all together and include the inverter self consumption and efficiency.
    Start with loads,  next battery to support the loads, finally array/charge controller, to support  the battery requiments and subsequent loads days of autonomy etcetera. Having a generator is helpful but remember there is a charger required, if the need to supplement  the solar is a requirement, it usually is in temperate climates. Seriously rewind and start from  the beginning, you'll be a lot less dissapointed.

    So the question about a breaker box, for now you don't really need one as the  1500 W inverter more than likely has protection built in, (short circuit, over load and perhaps ground fault protection ) it can't supply enough current to trip a 15A breaker before shutting down on over load,  so if you're building for the future, it would be prudent to invest in the solar side first, keep the generator divorced for now to avoid complexity.......Just my opinions others may differ.
    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.
  • GloriaGloria Registered Users Posts: 3
    Without a breaker box how do I get power to other areas of the cabin, loft, living area, kitchen, bathroom?
  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Use a junction box splice the conductors  together fed from the inverter in parallel, later if upgrading the whole system to a larger inverter, which can exceed the rating of the conductors,  a small load center could be installed in its place.   
    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.
  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    IMHO, if you're going to have a panel eventually, I would go ahead and do it. It's true you could do without, but having separate circuits can be handy. If I have to solve a wiring problem or change a fixture, it's nice not to have to do it with the whole place dark, and the boss telling me to hurry up.
    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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