Sealed gel lead acid dead after a year.

YerfYerf Registered Users Posts: 39 ✭✭
Hey

So I have 24 x 2v 3000 ah sealed lead acid gel batteries. They are a year old and don't hold any charge. One of they recently blew up and I replaced it but they still don't hold charge. How can the whole bank be dead in a year? Any ideas? I seperated each battery and left it for a day and measured each battery. I've attached each batteries voltages. 48v battery bank individually measured https://imgur.com/gallery/X940F

Comments

  • mcgivormcgivor Registered Users Posts: 1,281 ✭✭✭✭
    Can you let us know exactly what  batteries they are, picture? , what charging source was used, voltage /current setpoints and so forth, as much information as possible. Initially without knowing any details, the fact one blew up may indicate over charging, but that's a shot in the dark.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • YerfYerf Registered Users Posts: 39 ✭✭
    These are the batteries in the picture. They are open from China. I use a victron 150/70 charge controller to charge them. The charger controller is set to default charging algorithm which is for sealed gel lead acid batteries.
  • mcgivormcgivor Registered Users Posts: 1,281 ✭✭✭✭
    There are various default settings set by a rotary switch, which setting did you use? What is the array size and configuration, total watts and input voltage? These are important to determine what went wrong, a make and model, or a link th the battery would be helpful, to establish what batteries they actually are, the picture provided is of little help. 
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • YerfYerf Registered Users Posts: 39 ✭✭
    edited October 17 #5
    Hi

    The settings are algorithm 2 which are absorption 57,6 V float 55,2 v

    The solar array is around 100 V and 300 amps seperated into 5 charge controllers.

    Sorry but the batteries were bought from https://just.m.en.alibaba.com

    Nothing on there about the specific model.
  • PhotowhitPhotowhit Solar Expert Posts: 4,253 ✭✭✭✭
    edited October 17 #6
    That is a huge battery. What was the load? How far were you drawing them down? 

    Are you sure it's a gelled battery? Sometimes people get confused with Absorbed Glass Mat (AGM) batteries.

    Regular deep rapid discharging is not the best use of gel batteries. They don't do rapid discharges well. They also must be charged at a lower rate than AGM batteries. Usually at 1/16th to 1/20th of their capacity, not a good choice if you are deeply discharging them as solar might not offer enough time to totally recharge them and then require the array to be angled in separate directions to allow a longer charging time.

    You have 30,000 watts of array so 30,000/48=625, or more realistic charge rate of 75% of that or 468 amps or 15% of the battery capacity. About 2.5 - 3x the normal charging rate for a 3000 amp hour gelled battery.

    Here is some generic information about Gel batteries, hopefully you can get more information from the manufacturer.

    https://www.solar-electric.com/learning-center/batteries-and-charging/deep-cycle-battery-faq.html#Gelled Electrolyte
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • EstragonEstragon Registered Users Posts: 1,545 ✭✭✭✭
    According to the first image, cell voltages range from ~2.07 to 2.25, which would be equivalent to ~12.4 to 13.5v in a 12v nominal battery.

    You said these readings were taken after the bank was separated for a day, which I'm confused about. The readings suggest states of charge ranging from about 70%SOC to around float voltage. Were they being charged after being separated?
    Off-grid.  
    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
  • YerfYerf Registered Users Posts: 39 ✭✭
    > @Estragon said:
    > According to the first image, cell voltages range from ~2.07 to 2.25, which would be equivalent to ~12.4 to 13.5v in a 12v nominal battery.
    >
    > You said these readings were taken after the bank was separated for a day, which I'm confused about. The readings suggest states of charge ranging from about 70%SOC to around float voltage. Were they being charged after being separated?

    No they weren't charged after being seperated. I am suspicious that the high voltage readings mean the batteries have a short circuit.

    According to bmv 702 battery monitor the soc never went below 80%

    The batteries were oversized due to future expansion in electricity needs. They are definitely deep cycles gel batteries.

    Thanks for all your input
  • YerfYerf Registered Users Posts: 39 ✭✭
    > @Photowhit said:
    > That is a huge battery. What was the load? How far were you drawing them down? 
    >
    > Are you sure it's a gelled battery? Sometimes people get confused with Absorbed Glass Mat (AGM) batteries.
    >
    > Regular deep rapid discharging is not the best use of gel batteries. They don't do rapid discharges well. They also must be charged at a lower rate than AGM batteries. Usually at 1/16th to 1/20th of their capacity, not a good choice if you are deeply discharging them as solar might not offer enough time to totally recharge them and then require the array to be angled in separate directions to allow a longer charging time.
    >
    > You have 30,000 watts of array so 30,000/48=625, or more realistic charge rate of 75% of that or 468 amps or 15% of the battery capacity. About 2.5 - 3x the normal charging rate for a 3000 amp hour gelled battery.
    >
    > Here is some generic information about Gel batteries, hopefully you can get more information from the manufacturer.
    >
    > https://www.solar-electric.com/learning-center/batteries-and-charging/deep-cycle-battery-faq.html#Gelled Electrolyte


    The batteries were oversized for our needs. Although we have 3 x 10000 quattro inverters connected the battery soc never went below 80%.

    Also never saw the charge current higher than 300 amps. Mostly around 100 amps.
  • EstragonEstragon Registered Users Posts: 1,545 ✭✭✭✭
    > @Yerf said:
    > > @Estragon said:
    > > According to the first image, cell voltages range from ~2.07 to 2.25, which would be equivalent to ~12.4 to 13.5v in a 12v nominal battery.
    > >
    > > You said these readings were taken after the bank was separated for a day, which I'm confused about. The readings suggest states of charge ranging from about 70%SOC to around float voltage. Were they being charged after being separated?
    >
    > No they weren't charged after being seperated. I am suspicious that the high voltage readings mean the batteries have a short circuit.
    >
    > According to bmv 702 battery monitor the soc never went below 80%

    I don't think an internal short would cause resting voltage to be high, but others may be able to comment on this.

    Do the suspect cells get hot when charging?

    The battery monitor can, at best, tell the approximate state of charge for the bank as a whole. It appears there are significant variations in SOC between cells in your bank though. There are lots of variables that can confuse even the best SOC monitors. Mine can get out of whack after a few days of partial charging and discharging.
    Off-grid.  
    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
  • YerfYerf Registered Users Posts: 39 ✭✭
    > @Estragon said:
    > > @Yerf said:
    > > > @Estragon said:
    > > > According to the first image, cell voltages range from ~2.07 to 2.25, which would be equivalent to ~12.4 to 13.5v in a 12v nominal battery.
    > > >
    > > > You said these readings were taken after the bank was separated for a day, which I'm confused about. The readings suggest states of charge ranging from about 70%SOC to around float voltage. Were they being charged after being separated?
    > >
    > > No they weren't charged after being seperated. I am suspicious that the high voltage readings mean the batteries have a short circuit.
    > >
    > > According to bmv 702 battery monitor the soc never went below 80%
    >
    > I don't think an internal short would cause resting voltage to be high, but others may be able to comment on this.
    >
    > Do the suspect cells get hot when charging?
    >
    > The battery monitor can, at best, tell the approximate state of charge for the bank as a whole. It appears there are significant variations in SOC between cells in your bank though. There are lots of variables that can confuse even the best SOC monitors. Mine can get out of whack after a few days of partial charging and discharging.

    Didn't notice any heat.
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