Two chargers

bobbywarren
bobbywarren Registered Users Posts: 1 ✭
in Solar Beginners Corner #1
I am setting up a new off grid project, I was wondering if it is okay to attach a wind turbine charge controller and I solar charge controller to the battery bank!
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
    There is generally no problem having multiple charging sources for a bank, provided the sources are properly set up (eg properly sized dump load for wind controller, overcurrent protection, etc.).
    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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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #3
    Yes, but what's really important, is that the wind turbine is mounted well too. you don't want that coming down on your house or blades flying into your car.
    Wind turbines often need a "Dump Load" and not a regular charge controller, be sure you get the right setup for your turbine.
    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
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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #4
    If I ever go off grid I will probably be running at least 3 chargers minimum.
    No problem if it's wind and sun or sun and sun, or sun plus sun plus wind as long as you don't charge the battery bank too fast.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • NANOcontrol
    NANOcontrol Registered Users Posts: 273 ✭✭✭
    #5
    You can put a dead chicken between the source and a battery and still charge it. I run multiple chargers and if you hang around and watch them a long time it is pretty easy to see them get confused. Chargers all have an algorithm they follow based upon a battery not being connected to anything and with only a single charge source.  Just how does it know when to go from absorb to float when It has no idea of what is actually happening?  Only in a standby power setup can it really be sure.  In an actively used system it generally rarely gets out of bulk. Does it matter that much? Probably not. The over design of systems keeps it from being a major factor.
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  • zarapp
    zarapp Registered Users Posts: 8 ✭✭
    #6
    oil pan 4 said:
    If I ever go off grid I will probably be running at least 3 chargers minimum.
    No problem if it's wind and sun or sun and sun, or sun plus sun plus wind as long as you don't charge the battery bank too fast.
    Can you please explain this ? I through banks can be charged with 10% of its maximum AH (example 250ah/12v battery can be charged with 25a/12v charger) to avoid faster end of life . Or thats only the case with single batteries and for banks they can be multiple chargers and go over that 10% ?

    Regards
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #7
    1x solar charge controller
    1x AC to DC charger (backup genset)
    1x Wind Turbine charge controller

    Note that depending on AH rating of battery bank and size of your solar array, you may have 2-3 solar charge controllers (maximum 60-90 amps maximum for typical larger MPPT solar charge controller). You could have 2 or more AC to DC battery chargers (again, depending on the size of your system).

    Note that Wind Turbine Charge controller can be a very "different" animal. Some are "dump controllers" where they "turn on" a resistor bank (electric heaters)... Battery voltage gets over "set point", the dump charger turns on.

    Other wind turbine charge controllers may simply turn off the wind turbine, or some combination there of...

    You need to measure/estimate your loads/energy needs. Size the battery bank to support those loads. Then size the charging systems (Solar is one charging system, Genset is another, wind is a third, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #8
    The max charge rate depends on the battery type. For example, some AGMs can take well over C/10.

    Slower charging can be better for some batteries, but designing for much slower than C/10 for full-time off-grid means running out of sun more often. A bit of a trade-off.

    It doesn't matter if it's a single cell or a large bank. It's the design of the battery (cell) that determines max charge rate.
    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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  • zarapp
    zarapp Registered Users Posts: 8 ✭✭
    #9
    @Estragon thank you . So basically to stick to 10% of the total AH unless the manufacturer has specified different option .

    Regards
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #10
    Yes. My flooded L16s take 15% of C sometimes and seem okay with it. Doesn't happen often though, normally only on a day with a really gloomy morning that gets suddenly sunny around noon. Most days, by the time the panels are in full sun, the system is in absorb and batteries won't take full current anyway.

    IIRC, I have CCs limited to ~15% of C.
    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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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #11
    More or less, >~13% rate of charge, Flooded Cell Lead Acid batteries--They can run the risk of overheating if charging quickly (high current).

    Normally, for most people, the voltage set point (Absorb) should be low enough for the battery bank to absorb less than 13% as the bank nears fully charged.

    FLA batteries at less than ~80% State of Charge are much more efficient at charging and high charging current does not generate much heat during this charging phase.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    edited October 2018 #12
    > @zarapp said:
    > @Estragon  thank you . So basically to stick to 10% of the total AH unless the manufacturer has specified different option .
    >
    >
    >
    >
    > Regards

    That is why I would use a fork lift battery.
    Charing at up to 25% of the name plate C rate is normal for them.
    Fork lifts that stay in refrigerated areas charge even faster just to help keep the batteries warm during use.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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