No power at night

castilloj
castilloj Solar Expert Posts: 208 ✭
in Off Grid Solar & Battery Systems #1
I have a fx2524 connected to 8 rolls s600 batteries, and i run my 11kw generator from 8 am to noon. From noon till 6pm i use my inverter for power. then from 6pm till 10:30pm i run the generator again.
lately ived been having problems like when i switch to inverter power at night. The PV/Output Breaker in My E-panels trip, causing the house to not have power at night.
The thing is that it only happens at night not during the day. any suggestions?
Also i have another question im using 8 s600 batteries on a 24 volt system. i only have one inverter, and when i talked to Rolls they mentioned that i would need to have around 25-28 amps AC to properly charge 2 strings of batteries. My question is could i just use 4 of the batteries and still get the same ammount of power at night? and have the batteries get a real charge?

Thanks
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: No power at night

    Let's see, Rolls s600 is 6 Volt, 450 amp hour.Eight of them in a 24 Volt configuration would be two strings of four parallel for 900 Amp hours. That's about 10 kW hours of power. Lot's of capacity for off-grid. But it's going to require lots of charging.

    Outback VFX2524 has only a 55 Amp charger - pretty slim for that much battery. Having 11 kW of generator is irrelevant as the inverter itself will only draw about 1600 Watts. Add maximum load capacity (2.5 kW) and you've got more than twice the generator you need, so to speak.

    The big question is; what are the loads you're trying to supply?

    Also, check the SG on the batteries to see if they are getting charged fully. Check the charge setpoints on the inverter as well, including Absorb time.

    Is there any PV on this set up? If so, how much and what charge controller?

    It's odd that the breaker would trip out. Usually the inverter faults from overload or low Voltage first.

    Please supply us with some more system details so we can get a better feel for how it should operate and figure out why it doesn't.
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  • castilloj
    castilloj Solar Expert Posts: 208 ✭
    #3
    Re: No power at night

    Attachment not found.I use about 6 amps AC from 11pm till 8 am. running a tv,satellite dvr , 3 ceiling fans,internet modem, and 2 box fans.
    I have 8 photowatts pw-1000 and 8 Astropower AP-120
    also ive never know excatly what to set charge setpoints or float. so i just left them on the default setting.

    i also have solar panels which right now at 11:32 am im getting:
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: No power at night

    6 Amps @ 120 Volts = 720 Watts. Times nine hours = 6480 Watt hours.
    Are you sure? That's a pretty healthy consumption. More than half the available Watt hours.

    Eight Astropower @ 120 Watts each = 960 Watts.
    The Photowatts seem to be 100 Watts each so that's 800 Watts.
    Grand total of 1760 Watts. Derated 1355 Watts, divided by 28.4 Volts = 47 Amps. A minimal charge current for 900 Amp hours of battery but doable (depending on loads).
    But if you look at the "harvest" you get something like this: 1355 Watts * 4 hours = 5420 Watt hours.
    I'd run PV Watts to check potential in your area. http://rredc.nrel.gov/solar/calculators/PVWATTS/version2/

    With the additional generator charging, however, it should make it.

    Definitely need to check the Absorb Voltage set point and the Absorb time. As well as the batteries' SG. It looks a bit like undercharging. Providing we're looking at the right fault. If the breaker is tripping but the battery Voltage remains high, then perhaps their is a wiring fault or some load assignment it can't handle.

    P.S.: I can't actually see the attachment on my netbook. There may be a vital clue lurking in the data there.
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  • castilloj
    castilloj Solar Expert Posts: 208 ✭
    #5
    Re: No power at night

    absorb setpoint-28.8
    absorb time limit-1.0 hrs
    Float setpoint-27.2
    float time limit-1.0- hrs
    refloat setpoint-25.0 vdc
    EQ-28.8
    Eq time-1 hrs

    Batteries are at 25.21 vdc
    right now using 5.0 aac
    batteries are :
    1.225/1.225/1.225 --1.225/1.225/1.250--1.225/1.100/1.225--1.225/1.210/1.210
    1.225/1.210/1.225-- 1.210/1.210/1.210--1.225/1.225/1.210--1.210/1.210/1.210


    Array Voltage-49.27v
    Array Current-24.5 amps
    sweep VMP-49.27
    Sweep VOC-67.09
    Sweep Pmax-1182 watts

    Battery Volatage- 25.68
    Target Voltage -30.61
    Charge current-36.8 amps
    output power-1170watts
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #6
    Re: No power at night
    castilloj wrote:
    1.225/1.225/1.225 --1.225/1.225/1.250--1.225/1.100/1.225--1.225/1.210/1.210
    1.225/1.210/1.225-- 1.210/1.210/1.210--1.225/1.225/1.210--1.210/1.210/1.210

    Big problem there... May be a bad cell/battery. That cell is pretty much dead and even if you get it recharged, it still may not last very long.

    That can cause its string to over charge and the parallel battery string to undercharge/discharge with light loads on the system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • castilloj
    castilloj Solar Expert Posts: 208 ✭
    #7
    Re: No power at night

    Should i just use 4 batteries in series?
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #8
    Re: No power at night

    1 hour in absorb is too little in my opinion. Since you're running on the generator, I'd increase this to around 3 hours to make sure you're properly charging.
    Too little time in absorb = sulfation = premature battery death
    Too much time in absorb = more water use
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  • castilloj
    castilloj Solar Expert Posts: 208 ✭
    #9
    Re: No power at night

    Ok i just changed absorb to 3 hours.
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