Generator Charging Issues

DclineDcline Registered Users Posts: 17 ✭✭
Good Morning,

New to this technolgy so please bear with me if I don't know all the lingo.

I am working with an off grid system.
(2) XW5548 Inverters
Com Box
Conext Battery Monitor
Kohler 14RESA Generator
Batteries (830 AH)

My problem is the following:
Generator starts as required by the trigger setting, the inverter is reading about 1.5KW (lights and various loads) with the AC2 LED lamp flashing and then switches from reading KW to Amps on the front panel and rises to around 99Amps and shuts down and resets and starts this over again.

The other issue I have is that I can hear the generator change speeds when the above happens and after a couple of times the generator with go off on a faulure of Low Frequency.

Please let me know your thoughts.

Thanks Dan


  • BB.BB. Super Moderators, Administrators Posts: 33,002 admin
    No expert here... But it sounds like your AC2 input maximum branch circuit current rating is not set correctly?

    14,000 Watt genset rating / 240 VAC = 58.3 amps max continuous rating

    Some of the equipment will, if you program 60 amps "branch circuit" rating will only draw 80% of that:

    60 Amps max rating * 0.80 = 48 amps functional draw

    Which is what I would suggest you start at for a maximum draw for your genset.

    Your genset will surge to 20,000 Watts (I think, just a quick looks at the specs):

    20,000 Watts / 240 VAC = 83.3 Amps max

    So, drawing 99 amps (@ 240 VAC on AC2 input?) does not seem right.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • MichaelKMichaelK Registered Users Posts: 229 ✭✭✭
    edited December 2020 #3
    Have you changed the charging rate?  For my 6848, the default rate is 140A, which at ~50V would be 7000W.  I only have a 6000W generator.  By reducing the charging rate I can get the generator qualified by the 6848.  Funny thing is that my generator can output power up to about 36% (~50amps), but it can NOT be started at 36%.  It will do exactly the same thing you are describing.  I start it out at a very low 10% (14amps), let it run till completely warmed up, then incrementally up the percentage a point at a time till I get to about 36%.
    With a 830Ah battery, I'll assume you want to charge at about 83A?  That would be a 60% setting if you have the same 140A default?  At 50V that's >4200W.  That's a fairly hefty load even for a large generator like your Kohler.  That could get problematic if you want it to work with an AGS.
    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)
  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Do you have a means of adjusting the settings, system control panel  (SCP), ComBox, configuration tool or Gateway? The frequency acceptance  setpoints may be too narrow, or both inverters are changing at maximum capacity, they do ramp up so initially it may begin to charge but overloaded the generator when full output is reached.

    If the generator is audibly struggling that would be an indication of overloading, which in turn would reduce the frequency, did you or someone else commission the system.?
    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.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,354 ✭✭✭✭✭
    edited December 2020 #5
    Do you own this system? New owner?

    You need to know what frequency the genset is at when it connects. Do you have a means to read gen frequency? You can read this on the combox meters screen for AC2.

    The other issue with these older inverter/chargers is the stacking for multi inverter. Cables are good? Works fine without the genset?

    This needs to be solved ASAP because you can damage the input relays, or one of the two or both have been damaged. 

    I would get one of the units (the master) working correctly, reduce charge current and test. Then add the second. As MichaelK suggests you only need 80amps or a bit more to charge. Two chargers is too much for your bank anyway.
    "we go where power lines don't" Sierra Nevada mountain area
    E-mail [email protected]

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