Did I kill my battery's?

machineman
machineman Solar Expert Posts: 129 ✭✭✭

Got a lot of snow last month at my remote cabin, and its been cloudy almost everyday. I have my magnum 24V system do a inverter LVD shut down at 23V. Panels covered in snow it shut down while i was away. Fine this happens in winter often but usually only a day or so. But it stayed off (i know because I can remote monitor if its up) for an entire month until my next visit. But I have my Davis weather station wired directly to the batterys so I dont lose data logging, constant current draw even with LVD, likely a bad idea in this case but never had this issue in the 10years since Ive been on this system. The 24V battery bank measured 3V!!!, So dead that the Xantrex XW60 charge controller wouldn't even fire up even if there was sun. Turned on the generator and charged it up, everything seemed back to normal. Turned gen off and they held. Got 440ah 6V eight GC batterys that are about 1 year old. Cant believe its survived that, permanent damage?

Off Grid Cabin, 24V 440ah 6V GC battery bank, Xantrex MPPT60-150 CC, Magnum MS4024 inverter-charger, >1200w Solar bank

Comments

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭

    If the battery cases didn't crack from frozen acid, you may have dodged the bullet. At low temps, sulfation happens much more slowly, so although they may not be as good as new, they may still have a decent service life.

    I'd check them over carefully for any signs of physical damage (eg bulging sides/posts, etc) though.

    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
  • machineman
    machineman Solar Expert Posts: 129 ✭✭✭

    They are in a half buried concrete shed so temps inside probably didn't get below freezing. I didn't notice any bulging and they still were full of water. Will do a detailed inspection next month when Im back. I built an arduino Ethernet controller that monitors the battery voltage, temp, and lots of other stuff so I can see whats happening remotely.

    Off Grid Cabin, 24V 440ah 6V GC battery bank, Xantrex MPPT60-150 CC, Magnum MS4024 inverter-charger, >1200w Solar bank

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭

    Something similar happened to me a few years ago, and the banks survived :-)

    I added small vertically mounted "winter float" arrays to avoid the problem in future.

    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
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭

    Personally,  would be astonished if the battery bank survived this.  -   3 V total for  a 24 V battery bank.  It is most likely that a number of cells were charged in reverse during the discharge.   This is almost always DEATH to those cells.

    Your LVD setting seems to be a good,   conservative value.

    A bit surprising that the Magnum would be able to charge the battery from the generator when the battery was at 3-ish V.

    Good luck with the battery bank,   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.
  • softdown
    softdown Solar Expert Posts: 3,812 ✭✭✭✭

    3 volts in a 24 volt bank is scary. Let us know... S.G. is great but voltage works pretty well in my experience.

    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries