Chris11 Registered Users Posts: 130 ✭✭
edited September 2017 in Solar Beginners Corner #1
Never  mind.


  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    1. Optimum voltage for EQ depends on battery temperature.
    2. There is no "best" EQ time
    3. If you have EQ set to auto, I assume it would try again the next day. I wouldn't do it that way though.
    4. You would go through a bulk/absorb cycle before doing an Eq. When a normal EQ ends, the controller should go to float.

    IMHO, equalization is exactly that. You want to equalize the state of charge between cells in a battery bank, to the extent it's possible to do so. A cold battery will take higher voltage to EQ, and vice versa. When the weak cell(s) you want to correct stop rising in specific gravity for 30-60 minutes, you've done what you can with the EQ and you stop.

    Personally, I wouldn't just walk away from an EQ. It's a controlled overcharge, the keyword being controlled.
    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
  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    Equalizing voltage depends on batteries, Only flooded batteries should be equalized.

    Optimum voltage does depend on temperature, but also different batteries call for different voltages. It looks like the preset's for Flexmax should be 30 volts at 1 hour, it may have been set low incase someone tried to equalize agm batteries. I would leave it at 30.5 - 31 if you can't get info from the manufacturer. I would turn off equalizing if the batteries aren't monitored for SG and electrolyte levels monthly.


    Batteries like to be use, If they have live on float for 2 years, I would draw them down to roughly 50% of capacity and then fully charge followed by an equalizing charge. Equalizing is only done on fully charged batteries.

    Did you set the Flexmax to auto equalize? I don't think it will start for 30 days! it'll be a long wait. If they had no load and you started equalizing the voltage should have started to rise, even on an overcast day. I suspect you either set it to auto equalize or didn't force start equalizing.

    Yes, it should cycle back to a normal operation after equalizing.

    You say your batteries just maintain a float charge and don't go higher than 27.2 volts. Do you not see a brief period of Absorb that is higher than that in the morning? I think you can set the charge controller to only float the battery, but it's not something I would recommend, but perhaps if the battery wasn't used for 2 years... I just don't know.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Chris11
    Chris11 Registered Users Posts: 130 ✭✭

    Thank you so much Photowhit.  I really appreciate you taking the time to explain it to me.