Battery bank voltage

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stmar
stmar Solar Expert Posts: 373 ✭✭✭
I have 4 Lifeline GPL-8DL 255AH AGM battery bank, 24 volts 510ah. At this time it is off the grid, charging from solar only, and the only load is a Sunfrost 24 volt refrigerator. During the day the solar panels charge 28 to 27 volt range and at night the voltage stays in the low 26 to high 25 volt range. Since a fully charged 12 volt battery is 12.6 then a 24 volt system would be 25.2 volts, correct? If the bank is maintaining over that at night with no charge input then can I assume the batteries are in good shape?
We had a 4 hours grid outage at night and I switched over to the inverter, minimal loads, and the voltage did not drop below 25 volts with no charge input. After the outage I immediately charged the batteries by the inverter/grid.

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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,832 ✭✭✭✭✭✭
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    You need to know what Lifeline specs out for your battery. Voltages to the tenth of a volt, temp comp and average loads to determine battery health. A manual is attached that I think is your model.

    I always tell clients to attach the battery bill to the manual for reference😉😉😉
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,147 ✭✭✭✭
    edited June 19 #3
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    The static condition standing voltage of a fully charged Lifeline or Sun Xtender battery is 12.8v to 13.0v depending upon age. The absorb voltage needs to be 28.4v to 28.8v for 2-3 hours in order to reduce the buildup of sulfation.
    How old are these batteries?
    How are you determining that the batteries are reaching full charge?
    It is important to get a standing voltage reading for each battery, at least 2 hours after any charging or discharging.
    I deal with these batteries every day and I can tell you a lot about them!

    Marc
    I always have more questions than answers. That's the nature of life.
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,832 ✭✭✭✭✭✭
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    My favorite batteries are the ones I do not have to deal with every day 😉😉

    How are ya doing Marc?  Better than Boeing I hope!  Still loving the lake life?  



    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,147 ✭✭✭✭
    edited June 28 #5
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    We are alive and kicking, Dave! And you? Looks as though you are liking the Nevada life!
    We have intentionally scaled down the battery business by doing mostly fewer, larger sales to long-established industrial customers and some three-letter agencies. 
    My miter saw and table saw make lots of wood dust but collect no spider webs as we gradually remodel our lake home. (Maintaining the more rustic feel)  We started with a 1,250 sq ft garage and shop under the home and ended up with two more bedrooms, another family room, another bathroom, laundry room, and tornado shelter/storage areas. 
    We've been spending more time in Georgia because our youngest lives on Fort Moore (was Ft. Benning!)
     
    I always have more questions than answers. That's the nature of life.