Breaker for generator battery.....will this work?

porch13porch13 Registered Users Posts: 62 ✭✭✭
I have a 15KW Generac generator that is used for pumping water at a cabin.   Over time, the generator will slowly drain the battery.  I have a small panel and charge controller to charge the battery, but this time of year the sun is so far south that a tree blocks the panel.  To separate the battery from the generator when I'm not using it, I've thought about putting an in-line breaker on the positive battery cable.  Would this one fit the bill for that?:

https://www.solar-electric.com/mrcb-60-amp-dc-circuit-breaker.html

The generator calls for a battery with 350 CCA, but I don't know how that translates to what this breaker can handle.

Thanks much everyone!
Northern Arizona...4050 Watt off-grid system - Outback FP1 - Rolls 605 in a 48V bank

Comments

  • westbranchwestbranch Solar Expert Posts: 5,114 ✭✭✭✭
    You did not tell us how often you start the genny..?   I am not sure about that CB, since it has to take the surge draw of that starter ...  Do you have a Clamp DC Amp meter to at least get the running draw?

    why don't you use an AC battery charger? Probably 10A max as it would  charge when the genny is running.... for 1/2 hr or more when pumping..?


     
    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
  • mike95490mike95490 Solar Expert Posts: 8,030 ✭✭✭✭
    A breaker will pop when you start the genset,  Use a automotive disconnect switch, they mount right on the battery terminal
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • mcgivormcgivor Solar Expert Posts: 2,423 ✭✭✭✭✭
    The breaker is not rated to handle the current a starter draws which will trip the breaker, an automotive battery isolation switch would be far superior.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    900W  3 × 300W No name brand Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal as a backup system. 
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergencies and welding.
  • EstragonEstragon Registered Users Posts: 3,043 ✭✭✭✭✭
    Are you sure the generator draws the battery down over time? Is the draw down because the generator doesn't charge the start battery enough during a pump cycle, or because of generator electronics idle consumption, or because the battery sits around too long? It's also possible the partly shaded pv and/or controller self consumption is drawing power from the battery, not the generator.

    If the generator is drawing power when off, it may make sense to establish what it's drawing power for before installing a breaker (or switch) to cut DC power.

    If it could be something else, it may make sense to investigate those causes.

    I think there should already be a fuse or breaker in the generator - starting battery circuit, but I'm not sure opening it is going to solve the actual problem. IMHO, you need to define the problem properly first, then find the right solution.
    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
  • SolarMusherSolarMusher Solar Expert Posts: 172 ✭✭✭
    If you don't have an automatic start, just pull off the fuse on the controller board and it won't draw anything...
    Or install a 120vac line from your system to power the 120Vac built in charger to keep this battery full.
  • porch13porch13 Registered Users Posts: 62 ✭✭✭
    Thanks for the feedback, guys.  I'm completely off grid and there is no AC near the well house.  During warmer months the generator runs about once a week to fill a 500 gallon holding tank, and only run about every six weeks in the winter.  I'll look into the automotive battery isolator.  

    Northern Arizona...4050 Watt off-grid system - Outback FP1 - Rolls 605 in a 48V bank
  • mike95490mike95490 Solar Expert Posts: 8,030 ✭✭✭✭
    Is the generator Auto-Start ?  If so, it's the auto start circuit draining the battery, and if you isolate it, it wont auto-start
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • porch13porch13 Registered Users Posts: 62 ✭✭✭
    The generator does have an auto start option, but I don't use it.

    Northern Arizona...4050 Watt off-grid system - Outback FP1 - Rolls 605 in a 48V bank
  • westbranchwestbranch Solar Expert Posts: 5,114 ✭✭✭✭
    But is it disconnected? If not the parasitic draw is still there... regardless of us
     
    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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