Battery charging issues

seantseant Registered Users Posts: 9 ✭✭
so I bought 8 rolls surrete 487 amp batteries 

ran 2 strings of 4 then connected both strings.  When I turn on a load, roughly 287 watts, the batteries drop from full to 24.7 after about an hour.  

When I put a volt meter on them, one string is sitting 6.34 all 4 of them. The other string is at 6.23, neither string matches what CC is reading 

they are strung pos/neg each string..

There are 8 265 watt panels and no load today until 5pm.  

and I per an earlier thread, I’m bumping up to 48 volt Friday when new inverter/charger gets here 

is there a way to even out the charge in these while I wait?  And shouldn’t 487 amps be roughly 11 kWh hours of use, which shouldn’t even dent my battery bank after an hour

obvoulsy there is something I’m not understanding 


Comments

  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    The problem may be undercharging if the batteries are cycled daily, if flooded you need to check the SG to make sure all cells are ballanced, which they probably are not based on the individual voltage readings stated. What are your charging voltage settings and absorbtion termination method ? 

    Seperately charging each string would be a good starting point, regarding the voltage drop, what was the voltage after the load  was disconnected and given some time to recover?
    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.
  • seantseant Registered Users Posts: 9 ✭✭
    edited March 2020 #3
    After I turned off bigger load, one string went back to 6.33. The other still sits at 6.34

    i just put them in on Saturday..currently drawing about 56 watts, my CC says 25.0. 

    I set the absorption on the outback flex 80 at 4 hours, and the end amps at 18.  The CC shows that it never went to absorption today, and yesterday only for 7 mins
  • ThomThom Solar Expert Posts: 196 ✭✭✭
    It takes a while for the battery to stabilize after the load is removed. I turn off my system at night and in the morning look at the voltage . Last night it was 12.32v in the morning it was 12.52.  I would check SG if they are reg batteries.  Did you give them a commissioning charge ? 

    Good luck
    Off grid since 1984. 430w of panel, 300w suresine , 4 gc batteries 12v system, Rogue mpt3024 charge controller , air breeze windmill, Mikita 2400w generator . Added [email protected] 100w panel with a midnight brat 
  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Thom said:
    It takes a while for the battery to stabilize after the load is removed. I turn off my system at night and in the morning look at the voltage . Last night it was 12.32v in the morning it was 12.52.  I would check SG if they are reg batteries.  Did you give them a commissioning charge ? 

    Good luck
    Commissioning charge, that was exactly what my next question would have been being that they are new.
    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.
  • seantseant Registered Users Posts: 9 ✭✭
    I did not.   Up until this post, I had no idea what that was. 

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