Sunny Island LBM fault

3RFB
3RFB Registered Users Posts: 1 ✭
in Off Grid Solar & Battery Systems #1
I’m working on a DC Solar trailer that my son picked up at an auction. This trailer does not have the generator option.  The trailer has 2 Sunny Island inverters and battery storage and they were intended to supply power to 2 50 amp outlets. The batteries are fully charged and managed with a Midnight Solar charge controller. The issue I’m having is that even though the charge controller and inverter both show a full charge on the batteries, the system shuts down after about 10 minutes of connecting a load and shows a Low Battery Mode fault on the master inverter. The power coming off of the panels is good and the batteries were tested and found to be good. I’ve checked the battery management parameters on the inverters and they are set to the default settings. Any help or ideas anybody can provide would be greatly appreciated 
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,904 ✭✭✭✭✭✭
    #2
    Measure the voltage under load ! If there is a bad battery it could be breaking down with load. How were the batteries tested to be good?
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #3
    Generally,  these systems used Flooded Forklift batteries.
    Check the level of the electrolyte in EACH cell.  Each cell should have its plates  covered with electrolyte.

    You will need a good quality Hydrometer (perhaps from a Auto Parts store).  Get one of the turkey-baster types  --  glass tube,   glass float inside the tube,  with numbers on a scale, inside the float.  Measuring the Specific Gravity (SG) of each cell is the only real way to know the State Of Charge (SOC) of each cell,  and therefore that of the battery.

    Usually,  the Specific Gravity for these batteries,  when fully-charged, is around 1.285-ish.

    Battery monitoring devices are not often very accurate in reporting the actual SOC  of batteries.

    Please report the SG readings of each cell.

    All,  IMO,   Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #4
    There is not enough information provided to suggest what the problem may be, details on the battery type, capacity, nominal voltage along with the actual load being applied and at what voltage would be helpful.
    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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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #5

    Hello 3RFB,

    Do you have any info to report?  How is everything going?
    What are the "default  values" that you noted?  Need to know the Absorb voltages for the Classic Charge Controllers,  and for the Sunny Island inverters if these are used to charge your batteries.

    As noted above,  these DC Solar trailers usually have two FLA Forklift batteries,  about 500 Ah ea,  at 48 V.  Usually,  the target SG for full-charge IS 1.285.

    A typical battery info sticker picture is attached.

    Here may be a Link for a typical example of such a trailer:

    https://www.proxibid.com/DC-Solar-Trailer/lotinformation/54742303

    Please let us know how you are doing,   Thanks,  Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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