capacitors, inverters, and generators....oh my

t00ls
t00ls Solar Expert Posts: 250 ✭✭✭
in Off Grid Solar & Battery Systems #1
problem : while running generator with xw4548 in gen support mode, when ac or refrigerator kicks on, there is a flickering of the lights and it knocks the generator from supplying voltage and current to the inverter

inverter : XW4548
generator : DS4400E from durostar I use the 220v 30 amp outlet
batteries : trojan t-105  450aH
solar: 2100watts 1900 after derating ( average is usually around 1940 )
cc: XW mppt60/150

want to know if putting a run capacitor between the generator and inverter would aleviate this problem....if so, how do I wire one up...I've never dealt with capacitors
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    No, a capacitor is not a cure.   Your generator apparently is not beefy enough to start the compressor (those XW's are stout) and the XW senses the overload and disconnects the genset till it can qualify it again.

    What is the peak and run values of the genset ?  

    What are the generator settings in the XW - do you have the SCP or Combox ?  If the settings get fine tuned, this should go away,

    My3Kw genset can be charging batteries, and if the fridge or well pump kicks on, the battery charging throttles back for a couple seconds till the peak load is gone,


    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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  • t00ls
    t00ls Solar Expert Posts: 250 ✭✭✭
    #3
    the generator is brand new
    durostar 3500 continuous 4400 surge....plenty beefy for the loads

    I have the SCP...tried adjusting the low frequency to 47hz

    my thinking was going back to what chris olson was talking about when he was saying that the XW was too fast when a surge happens and just shuts off the relay for the AC2 input because it sensed a lower frequency

    "The XW is VERY fast in how it reacts to out-of-spec power output from the genset - it will react and prevent out-of-spec power from "hitting" the load within ~17-19 ms." -Chris Olson"

    I believe you used this in your post on demonstration of generator support

    so I was thinking that run capacitors inline with AC2 input would be able to gap that 17-19ms reaction like it would with a reactive load
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #4
    A capacitor would have to be tuned to the start winding in your fridge and AC motor, not an easy job even for an experienced electrician.
    Just hanging a cap somewhere in the system would do nothing good.  The cap gets connected to the starter winding,

    I've found that my "modern" 3Kw genset, Lies.  It has no reserve for poor power factor loads. and can't handle the same power as my antique generator.

    If your genset can't maintain FQ, it's being overloaded, or the governor is no good,  47Hz is pretty low,  What about the Genset Size and the amps settings ?
    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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  • new2PV
    new2PV Solar Expert Posts: 305 ✭✭
    edited September 2016 #5
    Only thing you can do without getting a bigger gen  is buy a soft starter for the fridge. I will find you the link.
    https://www.fairford.com/product/hfe/
    Try and lower the gen support amps so takes more surge from the battery.
    XW6848 inverter with 2 X mppt 60 150 CC , with Canadian solar 260Watt panels 2 x 3.5 kw array
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  • t00ls
    t00ls Solar Expert Posts: 250 ✭✭✭
    #6
    mike, you may be right about the governor ....seems like the rpms just drop when a new load hits
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #7
    The soft start option sounds like the better than a larger generator.
    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.
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