Generator bogs down, no longer charges battery bank

JasonDJasonD Registered Users Posts: 1
I could use some advice.  And I'm stupid, but perhaps someone can try to help anyway.

Some time ago my gen started to bog down when attempting to charge the battery bank. The batteries were old and I replaced them. Still wont take the load. So, I replaced the brushes and automatic voltage regulator in the gen (8000-10000 watt). But I still cannot get the gen to take the load - it engages, the indicator light appears on the inverter and the whole thing bogs down and tries again a few minutes later.  What is broken? Some kinda charge controller in the inverter?  I'm clueless as to what I need to do. Any suggestions are welcome - I want to learn.


  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    Some inverter/chargers have a setting to limit total generator current draw (charging + pass-through loads), and/or a limit for charging current.  On my Outbacks, I set these limits to ~75-80% of my diesel generator 30aac capacity.  I also let it warm up some, and have Outbacks set to delay charging for a couple of minutes to make sure that happens.

    Another thing that you may want to check is the inverter input range for frequency and voltage.  If the range is set too narrow, the inverter will drop the AC source, even though the genny can handle the load.  You may be able to widen the limits a bit at a time until the inverter holds the input.  Some inverters  have input terminals for (eg) AC1/grid and AC2/generator, with the grid input having pretty tight ranges by default.  Hooking up the genny to the grid input would likely cause what you're seeing.
    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
  • mike95490mike95490 Solar Expert Posts: 9,511 ✭✭✭✭✭
    If the generator governer is too slack and the RPM's drop too much, the inverter will disconnect.   Gotta get the frequency or RPM checked and set before the inverter will stick
    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

    gen: ,

  • MichaelKMichaelK Registered Users Posts: 221 ✭✭✭
    Which inverter do you have?  I have an XW+6848, and the default charge setting for that inverter is 140amps!  That's over 7000watts, which my generator is not capable of.  It also looks at the quality of the power produced (voltage, Hz, distortion) and won't let my generator supply more than about 40 amps at the level of quality it expects.
    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)
  • softdownsoftdown Solar Expert Posts: 3,597 ✭✭✭✭
    Another idea - You replaced the voltage regulator on the generator. What voltage is your generator now supplying?

    My own experience: Repair guy thought my Onan 3500 was a 3500 watt unit. It is a 2500 watt unit. He used a voltage regulator from a 3500 watt generator and my generator supplied 103 volts with that.

    Then I learned about the tiny brass screw on the back of many, perhaps most(?), voltage regulators that allows the same regulator to be used on a broad range of generators. 

    If your voltage regulator is, for example, capable of employment from 2500 watt gensets to 9000 watts then I would imagine the tiny brass screw would require a lot of turns in a large genset such as yours. 

    Low voltage could easily trigger problems with charging. 

    Then again, this may be extremely elementary and bothersome "trouble shooting". 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • fastlinefastline Registered Users Posts: 31 ✭✭
    Personally, I would disconnect the genny from the inverter and do independent testing on the genny with resistive loads to ensure it is running correctly.  You NEED an AC clamp meter that can read amps and frequency.  You need to know what the unloaded volts/amps/hz are, as well as loaded near the rated capacity.  Don't be shocked if your generator cannot do its rating.  I have tested many ratings are usually inflated and frequency and voltage sags WAY out of spec for me to accept.  

    You may be fighting mechanical problems as well.  I am an engine builder as well and its entirely possible that you are running into a fueling issue that is not letting the genny handle much load.  You will only know once you hit it with a known load.  I recommend things like stovetop heating elements to add load.  
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