Announcement

Collapse
No announcement yet.

Solar charge controller for small AGM batteries.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Solar charge controller for small AGM batteries.

    I have a small solar system with a 20W panel and 16Ah of AGM SLA storage, which is used nightly for running a few 5W 12V LED bulbs. I'm after a reasonable controller to try and maximise the lifetime of the AGM SLA.

    The Morningstar SS-6L-12V looks attractive, as it has a flooded mode which absorbs to 14.4V (good for AGM), but they're all gen3 which have a monthly equalisation charge to 14.9V for 3 hours (not so good for AGM).

    The battery states that its cycle-use charge voltage of 14.4-15.0V, so my question basically is, would that monthly 14.9V equalisation do much harm to the AGM, considering that it's still within its rated cycle charge voltage?

    My other option was the Morningstar Sunguard, but it only absorbs to 14.1V, which is apparently pretty bad for AGMs.

    Otherwise, if anyone has any suggestions for a different controller that would be suitable, and under US$50, feel free to recommend. Thanks

  • #2
    check the manuals (online) for the controller, I seem to recall there could be a jumper to select NO 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


    • #3
      Apparently it doesn't, the gen3 model of the controller has forced EQ when it's in flooded mode (to get the 14.4V). If you don't want EQ, your only option is go back to 14.1V gel mode. I've read this in a few posts on here too.

      Really seems like AGM batteries aren't catered for very well on solar controllers.

      Comment


      • #4
        Originally posted by GoneTomorrow View Post
        Apparently it doesn't, the gen3 model of the controller has forced EQ when it's in flooded mode (to get the 14.4V). If you don't want EQ, your only option is go back to 14.1V gel mode. I've read this in a few posts on here too.

        Really seems like AGM batteries aren't catered for very well on solar controllers.
        Do not use Gel Setting. The EQ is no real problem for AGM in your application. You want your charger to Absorb at 14.7 volts everyday or 2.45 vpc. 15 volts everyday would not hurt your AGM and do more good than harm because solar is not really capable of fully charging a Pb battery to start with unless your panel wattage is over sized. At 20 watts you are grossly undersized and not even near the recommended charge current rate for your battery. At best all you can generate is 1.2 amps, and your AGM needs 2 to 5 amps. You would be better served using EQ every day. If you were running 50 to 75 watts, you might have a reasonable concern, but at 20 watts you will never get that battery fully charged to begin with unless you shut down every other day to recover.

        Having said that there are a lot of controllers that have AGGM settings, you just are not using one. Keep in mind AGM cost 400% more than the FLA. They cost twice a smuch and last half as long. So not a lot of demand for AGM's.
        Last edited by Sunking; 06-29-2016, 09:37 PM.
        MSEE, PE

        Comment


        • #5
          I'll probably be looking to expand to 40-50W soon, just getting the controller out the way at the moment

          The other option would be to splurge for a ProStar PS15, which has an AGM setting, but curiously only absorbs to 14.15V in that mode with a 14.35V EQ. What are your thoughts on that, seems a bit low to me?

          Comment


          • #6
            Got a manufacture and model number for the battery?

            AGM operates at higher voltages than FLA or Gel. Generically 2.45 vpc. To make the Oxygen/Hydrogen recombine must be able to reach higher voltage to pressurize.

            I hesitate to give you exact voltages without knowing what battery you have. At high temps is lower like 2.35 vpc. At colder temps as high as 2,5 vpc.
            Last edited by Sunking; 06-29-2016, 10:35 PM.
            MSEE, PE

            Comment


            • #7
              I have some of these small AGM's that I got cheap

              http://cdn.securepages.co.nz/~dcpowe...iles/A12-9.pdf

              Comment


              • #8
                I have a few Synergy A12-9's that I got cheap recently.

                Comment

                Working...
                X