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Panel directly to battery vs pwm

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  • Panel directly to battery vs pwm

    For a small cyclic application I am wondering what's more efficient using a 12v solar panel (vmp 19v) :

    * directly connected (with diode) to a 12v lead acid battery and cut-off automatically @ for example 14.7v

    or

    A cheap pwm charge controller which automatically change to float mode, standard @ 14.4v charge and 13.2v float.

    It is for sure that the battery will be discharged every evening.


  • #2
    Originally posted by GeorgeF View Post
    For a small cyclic application I am wondering what's more efficient using a 12v solar panel (vmp 19v) :

    * directly connected (with diode) to a 12v lead acid battery and cut-off automatically @ for example 14.7v

    or

    A cheap pwm charge controller which automatically change to float mode, standard @ 14.4v charge and 13.2v float.

    It is for sure that the battery will be discharged every evening.
    Unless the panel wattage and charging amps is small, hooking it up directly to a battery can eventually cook the battery. While a PWM CC may be an added expense, it should "control" the charging amps and voltage going to the battery once it is charged.

    If there isn't anything to stop the charging or lower the voltage and amps a battery can be cooked.

    Comment


    • #3
      The charging will automaticly cut-off using this module , no stpdown.

      Comment


      • #4
        https://www.amazon.com/Battery-disch.../dp/B07VT18D41 i can buy this for 6usd @ a local online shop

        Comment


        • #5
          For off grid solar you want your battery to be able to take charge from the solar panel when ever there is sun available.

          IMHO Using a device that cuts charge totally is a poor option compared to an actual solar charge controller.

          Comment


          • #6
            The the difference on cost between the module, and a passable PWM Charge Controller, would be maybe $30 ? A $40 PWM controller that manages Absorb & Float charging is vastly superior to a simple on-off charger with only one charging mode, which will harm the batteries. You can't use a float charge for a cyclic battery
            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


            • #7
              To be simple:

              Mppt = power ini -> power out

              Pwm = amp in -> amp out

              How about panel directly connected to the battery?

              Its not about costs. Just curieus whether direct pv charging, no stepdown, is more efficient than pwm.

              Comment


              • #8
                Originally posted by GeorgeF View Post
                To be simple:

                Mppt = power ini -> power out

                Pwm = amp in -> amp out

                How about panel directly connected to the battery? ...
                ...
                Same as PWM. PWM is just a on off FET switch, no magic
                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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