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How to skip 5 days without solar charge

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  • #16
    Originally posted by Jfconst View Post
    ..... You say that you want to run on your batteries for 5+ days before charging. How do you do that with the solar panels trying to charge everyday?......
    I believe he accomplished it by:

    1) oversize battery bank, so that 5 days don't discharge below 80% full
    2 ) weather conditions blocked the sun so the panels had no harvest

    Chris is an experienced power generator, and was experimenting with different ways to limit charge cycle counts on batteries. Since then, I believe he's abandoned both wind and solar for winter (had snow & ice build up on vertical panels repeatedly and lost several sets of batteries) and relies on triple redundant generators for recharging and heat generation


    Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister

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    • #17
      Matrix, on the midnight classic, doing skip bulk charge, do you get any power from the panels during the day to run loads?

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      • #18
        Originally posted by Jfconst View Post
        Matrix, on the midnight classic, doing skip bulk charge, do you get any power from the panels during the day to run loads?
        Yes the panels are available for loads. The Classic will charge in Float on the skipped days. But you have power on demand if available from the panels.

        The caveat skip days is the possibility of sulfation in FLA batteries. The longer you let an FLA battery sit in a partially charged state, the more likely sulfation becomes. So its kind of a razors edge balance. One the one hand you might lengthen battery life with skip days due to less cycling, but perhaps at the expense of allowing sulfation to build up if skipping too many days thus making the former a wash.
        285Wx9 / MNClassic 150 / CSW4024 / TrojanL16H-ACx4

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        • #19
          Something like that could be done with the programmable setponts in the Morningstar MPPT controllers. You could set absorb for a measly 10 minutes daily, (or even 5) and there is another setting called Absorb Extend, where if battery voltage drops below a setpoint (user defined) a different length ( 3 hours ?) absorb time can be set.

          example from my program:
          Absorption Time: 2:10:00 h:m:s
          Absorption Ext. Voltage: 12.51 V (12V), 25.02 V (24V), 50.03 V (48V)
          [ if voltage drops below this, the Ext time is used for Absorb) ]
          Absorption Ext. Time: 2:50:00 h:m:s


          You can dial this in anyway you want.
          Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
          || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
          || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

          solar: http://tinyurl.com/LMR-Solar
          gen: http://tinyurl.com/LMR-Lister

          Comment


          • #20
            Originally posted by Matrix View Post

            Yes the panels are available for loads. The Classic will charge in Float on the skipped days. But you have power on demand if available from the panels.

            The caveat skip days is the possibility of sulfation in FLA batteries. The longer you let an FLA battery sit in a partially charged state, the more likely sulfation becomes. So its kind of a razors edge balance. One the one hand you might lengthen battery life with skip days due to less cycling, but perhaps at the expense of allowing sulfation to build up if skipping too many days thus making the former a wash.
            My battery rep says as long as I equalize every 3 to 4 weeks I will be fine. Any thoughts on this?

            Comment


            • #21
              Originally posted by Jfconst View Post
              My battery rep says as long as I equalize every 3 to 4 weeks I will be fine. Any thoughts on this?
              You actually only need to EQ when SG testing shows undercharged cells. That may be 6 months when you have sufficient Absorb time. At 3 weeks, you will be buying batteries sooner. More often than 4 weeks, you are doing something wrong, under sized pack, insufficient PV to properly recharge. It's worth running the generator 2x a week for a bit, to keep the batteries healthy, rather than waiting till they are sick and you cause a dose of Positive Plate Corrosion during EQ.

              Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
              || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
              || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

              solar: http://tinyurl.com/LMR-Solar
              gen: http://tinyurl.com/LMR-Lister

              Comment

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