Charge Battery Bank from Generator

nbaker
nbaker Registered Users Posts: 8 ✭✭
in Solar Beginners Corner #1
Hello experts!  I am in the process of setting up a 12V battery bank of 5 (105AH) deep cycle flooded (wired in parallel).  This will mainly be charged from 600 watts of solar panels using a mppt charge controller.  This system will just be used for emergency backup (fridge, lights etc).  My concern is that after a day without sun, I'm left with empty batteries.  I don't believe my 1500 watt pure sine inverter has charge capability.  I do have a 4,000 watt generator (harbor freight predator) that I would like to be able to use occasionally for 240 or other high demand appliances, while also changing the battery bank when the solar panels are not generating.  What are my options here using this generator?  I know its the least efficient and most costly option to charge the batteries, but were talking emergency use here.  AC out to $$$$ high amp charger?  DC outlet directly to battery bank?  PWM charge controller?  Jumper cable from my car to the battery bank?  Folks, I've seen all the above mentioned....Help set me straight here!  Thanks.
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  • 706jim
    706jim Solar Expert Posts: 520 ✭✭✭✭
    #2
    AC out to high amp charger. DC out from the generator will be very limited (and unregulated).
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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  • wellbuilt
    wellbuilt Solar Expert Posts: 763 ✭✭✭✭
    #3
    Iota makes a 12 volt charger that would work and charge at 15 amps ,but that is kinda low for a500 ah battery.
     I think the best think to do would be to add one battery an step up to 24 volts so 6 battery’s in Series parallel, then get a inverter/ charger 1500/ 2000watts . 
     This would make things easy 
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    If you are going to be doing this manually & occasionally, just get a 40A automotive charger.  Most of them are selectable for flooded, gel or AGM.  
    If you think this is going to happen more than every other week, then wire in a good PF corrected charger,

    For a normal 15AC circuit, that's 1800 watts, so for charging 12V you only have a theoretical  150A, but with losses, the most I would expect from a plug-in-standard-wall-outlet, would be in the 80A range

    I expect a 40A charger to pull 600-700w from an outlet - factor that into the load the generator sees !

    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 ,

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  • MichaelK
    MichaelK Registered Users Posts: 236 ✭✭✭
    #5
    My recommendation for you is to forgot about building a 12V system and go along with WBs advice and build at least a 24V system.  Once you leave the 12V arena, you enter the domain of serious solar systems running at 24 or 48V, where the choices for solid equipment are far higher.  Once you get to at least 24V, you can design a system that's designed for hard-wiring directly into a domestic power panel, with split-phase 120V/240VAC.  You can get inverters with a built-in charger that accepts 240VAC from your generator to charge the batteries.
    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #6
    1500 watts inverter is about the realistic limit for 12v.  Also have to watch out running MPPT controllers with 12v panels in parallel.  They may not have high enough overhead voltage to run MPPT controller.  Run panels in series.

    Better to go to an inverter/charger with 24v (<3kW) or 48v battery setup.
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