XW -MPPT60-150 Three stage Vs Two stage

sevenkts
sevenkts Registered Users Posts: 1
in Grid Tie and Grid Interactive Systems #1
My question is if the battery controller set at 2 stage is going to keep working after the absorption stage end to be able to SELL to the grid. I dont know if I have a problem. If I use the 2 stage the XW 6048 go to AC PASSTHRU at the end of the absorption stage. Is that normal. Can I be able to sell to the grid on 2 stage after the absorption stage finish. Or I need to use 3 stage to stay on FLOAT to be able to continue selling to the grid.
Do this FLOATING stage short the lives of my AGM batteries...

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  • SolaRevolution
    SolaRevolution Solar Expert Posts: 410 ✭✭
    #2
    Re: XW -MPPT60-150 Three stage Vs Two stage

    The XW components can be set for different charge settings. Your inverter(s) can be set for 2-stage and your Charge Controller(s) can be set for 3-stage.

    While the sun is shining and you are sending power to the grid your batteries are "floating" at the "Grid Supp Volts"
    When the sun goes down the batteries will receive no charging current unless the voltage falls below the "ReCharge Volts" setting.

    The inverter/chargers in 2-stage will not charge the batteries unless the grid goes off and comes back on or if the battery voltage falls below the "ReCharge Volts" setting. If the inverter/chargers are set for 3-stage they will provide current to maintain the float voltage setting 24 hours a day. If you follow the battery manufacturer's recommendations for a continuous float setting it may not hurt your batteries but it will use more energy than is necessary to maintain your system.

    I like to set the CCs for 3-stage so the batteries will receive a float charge if the grid goes out for an extended period.

    Note: In the most recent firmware versions (1005-BM11 or later) there is a way to make it so the batteries will receive a full bulk cycle before selling starts each day, but you probably should not do this with your back-up AGM batteries.
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