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Charging advice needed for Centennial CB6-400 AGM batteries

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  • Charging advice needed for Centennial CB6-400 AGM batteries

    New here, first post.

    Wondering if anyone is familiar with the optimum charge settings for Centennial CB6-400 AGM batteries in a seasonal, off-grid home. Documentation for this battery is scarce and dealer knowledge is zero for solar charging.

    The batteries (8 total) are 6-volt, 400 Ah, installed in a 24-volt off-grid solar system (4 in series to make 24-volts, then parallel for 800 Ah). My charge controller is an Outback FLEXmax 60.

    Here is a link to the battery spec sheet (the only information I have found):

    FYI, these AGMs are replacing a set of Trojan L-16s that lasted me for 12 years of seasonal use. Trojan was excellent in their documentation of recommended charge settings for this battery, even for off-grid charging, and I’m hoping to find similar recommendations for the Centennials.

    I also have a TriMetric meter and am open to suggestions on what settings to put in it.

    Any and all suggestions and recommendations welcome, particularly when it comes to charge settings for 10 months of storage. (The lowest temperatures the batteries will experience is around 22 degrees F.)



  • #2
    I would set Bulk/Absorb charging setting to 29.6 volts, Float to 27.2. For storage I have had good luck setting bulk/absorb/float to 27.2 This keeps the battery fully charged without any aggressive current flowing unnecessarily flowing.
    I would set the Tri-Metric to 29.5 for full charge and 800 amp hours capacity.
    2 Kw PV Classic 200, Trace SW 4024 460ah,


    • #3
      Thanks, littleharbor2. The manufacturer recommended 29.2 volts (and between 1 and 2 hours; we used 1.4 hours) for the Absorb setting, and 27.2 volts for Float--those are the settings we used for the 2 months we were on site. For storage, I did just what you recommended: 27.2 volts for both Absorb and Float. (Absorb time was also decreased to 1.0 hours.)

      On the TriMetric, the installer (very, very knowledgeable guy who did the original solar installation 12 years ago) used 29.1 volts and 8 amps (and zero time) for the "fully charged" critera.

      Again, thanks for the information.