Mixed Charge Controller Inputs

Mountain Don
Mountain Don Solar Expert Posts: 494 ✭✭✭
in General Solar Power Topics #1
By that I mean can one charge controller, such as a Outback FM60, be used to control the output to the batteries from two or three different sources, like a PV array, a windgen and an engine powered generator simultaneously?

I do not think that can work, but someone else says it can be done. Thanks
Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: Mixed Charge Controller Inputs

    If someone figured out how to do - show us.

    I don't believe it's possible, and still retain any efficiency of the MPPT benefit.
    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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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: Mixed Charge Controller Inputs

    I'm not saying it can't be done, but it's a bad idea. The reason being the varying outputs from different charge sources will have the MPPT going crazy trying to find the charge point.

    Wind gen and MPPT don't get along because of this; the gen's output changes too rapidly for the charge controller to work efficiently. Supposedly several companies are coming out with units designed for wind.

    What exactly do you mean by "engine powered generator"? 12VDC automotive?

    In general, even if you have two different arrays of PV you want two different CC's.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Mixed Charge Controller Inputs

    It would be very likely that having mulitple types of sources for a single MPPT will not work at all well for you...

    MPPT basically looks at the equation Pmax=Imp*Vmp and tries to play around with I and V to get Pmax.

    If you have multiple power sources (wind, solar, and generator) all connected to the input of a single MPPT controller--there is no one place on the power curve where a single Vmp and Imp will give you maximum power for everything.

    Also, some devices (such as Wind Turbines) have very different I*V curves and responses--A standard solar charge controller would (my guess) have great difficulties in trying to figure out the opimum power point and track it...

    Also, solar PV panels can be "turned off" without any problems. A wind turbine typically needs a load to prevent over-speed / self-destruction. There is no way a single controller can take all three inputs at one time and have anything work well.

    Midnite Solar is working on a (hopefully this year) release of a MPPT charge controller for wind turbines--and it is supposed to allow small wind turbines to capture several times the amount of power vs just hanging a 12 volt battery on a wind turbine.

    Others (Outback?) may also be working on a Wind Turbine version of their charge controller too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    #5
    Re: Mixed Charge Controller Inputs
    Cariboocoot wrote: »

    What exactly do you mean by "engine powered generator"? 12VDC automotive?

    More or less, but actually a 48 VDC output. That matches the panels and wind gen in the questionable setup. It's not mine so I don't have all the nitty gritty details.


    It simply seemed to me that having different types o inputs would, or could, have some incompatibilities.
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #6
    Re: Mixed Charge Controller Inputs

    in a carefully engineered and controlled situation it might work, but you should not do it. too many variables and possibilities for things to go wrong. wind gennies are totally another animal in their requirements and varies widely between makes and models. i'm also assuming the generator would have a filtered 12vdc output which is unlikely. if done, i would recommend one type of a source on a cc at a time and if 2 are used after careful consideration, planning, and advice each should be able to be individually switched out of line and fused properly.
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #7
    Re: Mixed Charge Controller Inputs

    There was an interesting thing I noticed in the FM60/80 spec sheet:

    http://www.outbackpower.com/pdfs/spec_sheets/flexmax.pdf

    "Hydro Turbine Applications Consult factory for approved Turbines"
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  • mshen11
    mshen11 Solar Expert Posts: 185 ✭✭✭✭✭
    #8
    Re: Mixed Charge Controller Inputs

    dont want to hijack this thread but i have two simliar questions:


    1. can you have a bunch of charge controllers and have their outputs hooked up to the same battery bank?

    2. can you have a bunch of charge controllers and have their inputs come from the same (huge) panels?

    3. can you have 1+2 together (assuming it is possible for 1, and possible for 2)?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: Mixed Charge Controller Inputs
    mshen11 wrote: »
    dont want to hijack this thread but i have two simliar questions:


    1. can you have a bunch of charge controllers and have their outputs hooked up to the same battery bank?

    2. can you have a bunch of charge controllers and have their inputs come from the same (huge) panels?

    3. can you have 1+2 together (assuming it is possible for 1, and possible for 2)?

    1. Yes.

    2. No.

    3. As above.

    Want clarification on that? :D
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  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    #10
    Re: Mixed Charge Controller Inputs

    Re #2. The manual specifically states that parallel FM60/80's can not be used when fed from the same panels. The panels need to be separated. Two groups of panels with 2 controllers; 3 with 3, etc.
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #11
    Re: Mixed Charge Controller Inputs

    1. yes.
    2. yes. (sort of)
    3. no

    You can feed one bank from more than one controller from seperate panels.

    You can feed more than one bank from the same panels with seperate controllers.

    You cannot do both. And on #2, there is no way to perfectly balance the controllers, so it is quite possible that one controller would hog 90% of the panel output. In theory you could get anything between a 50/50 split and a 99/1 split. There are other issues also, so definately not a good idea.
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  • mshen11
    mshen11 Solar Expert Posts: 185 ✭✭✭✭✭
    #12
    Re: Mixed Charge Controller Inputs

    so can i answer my own question by saying:

    1. always
    2. not unless you want major problems
    3. in theory yes but see #2 (or is it an absolute no?)
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #13
    Re: Mixed Charge Controller Inputs
    mshen11 wrote: »
    so can i answer my own question by saying:

    1. always
    2. not unless you want major problems
    3. in theory yes but see #2 (or is it an absolute no?)

    Yes.

    1. Multiple charge sources each with its own controller will read the batteries and adjust their output accordingly. In theory, if the batteries need 20 Amps and you've got two sources capable of producing 20 Amps each will contribute 10 Amps (not in reality, of course - too many variables). Best case is with a system like Outback's where the different CC's can communicate and maximize output potential.

    2. For Windsun's reasons I said "no"; the output from one array has only so much power to it, and there's no telling how it would get divided up by different controllers. Sizing an array for one controller is best: they have limits based on max. input voltage, output current, system voltage, etc. So you can't put up a "really big array" and have it feed multiple CC's - it would be too much power for any given one.

    You can charge multiple battery banks from one array/controller. I think Bluesky even makes a specific "dual bank" controller? Others can be arranged to switch to second banks at certain conditions.
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