absorption and float voltage

giovi
giovi Registered Users Posts: 20 ✭✭
Hello,
I have a 24v solar instalation and I would like to know how to setup the volts for
Absorption and float in my FM80 outback controller. my batteries are duracell sligc115, 6v 230ah

Comments

  • giovi
    giovi Registered Users Posts: 20 ✭✭
    What I really need to know is the voltage of each stage.
  • Chris11
    Chris11 Registered Users Posts: 130 ✭✭
    For what it's worth....
    My Interstate Golf Cart batteries according to Interstate (I phoned them) are 29.4 for Abs. 2 to 4 hours, and 26.04 for float.  Your Duracell may have been manufactured by the same company that manufacture for Interstate but you could phone Duracell to find out for certain.
  • giovi
    giovi Registered Users Posts: 20 ✭✭
    Ok, thank you very much!!
  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    edited August 2018 #5
    Are your batteries Sealed or are they Open Cell FLA?

    If Sealed there are plenty of folks on the forum that can help,  I do not know much about sealed but the charging parameters are slightly different than FLA

    But if FLA,  you will first need to get a good quality Temperature Hydrometer (not the auto parts store floating balls type), or you will never know if you get fully charged nor be able to truly monitor the health of the bank. 

    As to charge voltage settings,  you are at an OK starting point with 29.4v  Would be best know the manufacture spec,  but short of that,  all Solar charging (if that is what you are doing) is a balancing act between over and under charging.  You charge,  test, and adjust absorb and float up or down depending on the results.
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    edited August 2018 #6
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Duracell sligc115, 6v 230ah, flooded golf cart type, manufactured by East Penn
    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.
  • giovi
    giovi Registered Users Posts: 20 ✭✭
    Yes, they are open lead acid batteries.
    I have 12 of them. 690 ah in total.
  • giovi
    giovi Registered Users Posts: 20 ✭✭
    The factory default of the battery charger for abs is 28.8v and float is 27.5v
    its okay?
  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    Are the Batteries new?  OK so short of having the specs,  I would do a good bulk / Absorb charge with absorb set on 29.4v +/- (for a 24v battery bank), absorbing for a few hours or more.   Then do a 1 hour Equalization charge at 30.5 to 32.4v max and Monitor the temp that they don't get too hot.   You can actually EQ in 1 hour increments until the SG stops rising, but you must stay with the batteries to monitor temp and SG.  Once that is done,  I would take a Specific gravity reading of all cells with a good temp compensated hydrometer.  Write down all the cells specific gravity.  Make sure all cells are close in range to each other (20 points or less) and that the SG has risen to around 1.275 (if you know manufacture spec for SG even better).    This will establish a baseline for the future and also give you a good commissioning charge of the bank. 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    edited August 2018 #11
    giovi said:
    The factory default of the battery charger for abs is 28.8v and float is 27.5v
    its okay?
    If you are charging with AC it is probably fine,  but if you are charging with solar it might be low depending on your location,  size of array and number of daily sun hours.
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • giovi
    giovi Registered Users Posts: 20 ✭✭
    the batteries only have 7 months of use. I charge them with solar energy. (Off grid use)
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited August 2018 #13
    giovi said:
    The factory default of the battery charger for abs is 28.8v and float is 27.5v
    its okay?
    One thing to remember, charging specs are usually based on grid power with unlimited hours of energy available, but as this is an off grid application the charge time is very limited, therefore higher voltages may be required, it's a ballancing act getting the right parameters. What charger do you have, are there programming functions, remote temperature sensor, what are the charging amps, array capacity, total battery capacity, what is the depth of discharge, all relevant information. From a standby point of view 28.8V may work, but cyclical use it is a different ballpark, but without details it's all speculation.
    Edit :  FM80 means programmable so options are available, all other details are still  relevant. 
    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.
  • giovi
    giovi Registered Users Posts: 20 ✭✭
    The charger is a Outback fm80.
    I only use 25% of the bank of batteries.
    the voltage of the batteries in the morning is 24.8v.
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    In the beginning everything may appear good, time will reveal weakness, so many have fallen into the trap, me included, well almost, but seriously provide as much information as possible, it's really 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.
  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    edited August 2018 #16
    With solar you are probably going to have to use higher voltages for absorb than 28.8v.  28.8v is not even at the gassing stage. 
    - Do you ever add distilled water to the cells?
    - Are you discharging to around 75% each day?

    If so,  and you have never added water to the cells, I would think you are way undercharging the bank (just a guess without a hyrdo) if it has been in operation 7 months.  I would crank up the absorb voltage to 29.6v,  and get a good temp compensated hydrometer (see links above) and test all cells.

    You also have quite a few batteries, so I am guessing you have more than 2 parallel strings (4s 3p ??).   At 7 months with that many in parallel you are sure to have gotten cell / battery imbalanced by now - especially if you have not had to add water and have never done an EQ charge at voltages over 30.5v.  If you have never done a good EQ charge, you are way over due.  I would go thru a full charge cycle and then do an EQ ASAP,  even using AC or gen power to complete.   It make take several hours of EQ to get the batteries to rise fully and the cells to balance,  so be prepared for a day long project. You have probably been deficit charging and cells will be out of balance.  You cannot know with out a hydrometer.  But I would EQ soon.  IMHO
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • giovi
    giovi Registered Users Posts: 20 ✭✭
    Okay, I have no more information on these batteries and their specification.😣
  • MrM1
    MrM1 Registered Users Posts: 487 ✭✭✭✭
    edited August 2018 #18
    Not ideal, but No problem,  but see mine and mcgiver's  post above (if you can answer the questions the forum can help better).   All the more reason you need a hydrometer.
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    My current system is 1500W array, 8×220 Ah FLA golf cart type, 24V nominal 4series 2 parallel, battery charging specs unknown, depth of discharge ~30%, charging voltage 30.0V bulk for one hour into absorbtion then 29.6V for the remainder of 180 minutes or 2% of battery capacity,  which ever occurs first, float 27V, all temperature compensated. Full sun around 1140W or 36A, plus or minus, depends on battery voltage, gassing moderate, water consumption 3.4 liters every 6 months, 18 months in service, equalization time 1 hour every 6 months at 32V, so far so good, parallel ballance good, both charge and discharge. What works for me may not nesesarally work for you but it is an example of monitoring a 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.
  • giovi
    giovi Registered Users Posts: 20 ✭✭
    I have 6 solar panels of 260w in two string of three panels in series.
    the batteries are in three string of four. 3x4 = 12 batteries
    I do equalizations once a month at 30v for one hour. and I add distilled water before
    the hydrometer that I hagve is a cheap one, the cells show the same specific gravity.
    the system at the moment worked well, just that it was not sure about the values ​​of abs and float.
    another thing that causes me doubt is that when I add water to the batteries the density drops and it takes to recover
  • BB.
    BB. Super Moderators, Administrators Posts: 33,422 admin
    Generally, check the water level covers the plates (at least), then charge/equalize (add enough water to cover the plates if needed).... Then add water (not to the top) when charging/EQ is finished.

    This helps prevent bubbling/heated-expanding water from overflowing the top the battery.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • giovi
    giovi Registered Users Posts: 20 ✭✭
    Thank you all! Your comments were very helpful, I appreciate👍