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  • Low volts batteries at night.

    Hi my name is Luis, I'm in the military and currently I'm stationed in Hawaii. I have an small off grid solar system, running 2 laptops, a 50 watts lamp, a printer, internet router and a internet modem.
    I have 7 batteries (5 AGM) (2 marrines) total of 513AH, 430 solar watts panels and a Go Power! GP-SW1500-12 1500-Watt Pure Sine Wave Inverter. Somenights my batteries will show low voltages, pass 50% all away down to 11.9 volts. Do I need more batteries? Thanks for any help.

  • #2
    Sounds like 1 or more of the batteries are bad. Check, charge and recheck each on indiviually.

    Also you shouldn't mix battery types or the same battery of different ages.

    WWW

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    • #3
      Originally posted by Wy_White_Wolf View Post
      Sounds like 1 or more of the batteries are bad. Check, charge and recheck each on indiviually.

      Also you shouldn't mix battery types or the same battery of different ages.

      WWW
      +1

      I think your answer about the mix of battery types (AGM & FLA) is the issue.

      Also from another of the OP's posts, those 7 batteries have different Ah ratings. My guess is that they have not been charging and discharging equally and now he has one or more of those batteries going bad.

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      • #4
        Originally posted by Wy_White_Wolf View Post
        Sounds like 1 or more of the batteries are bad. Check, charge and recheck each on indiviually.

        Also you shouldn't mix battery types or the same battery of different ages.

        WWW
        But my system is a month old. Do I have to charge every single one by themself? How do I check them?

        Comment


        • #5
          Originally posted by zuliwito View Post
          But my system is a month old. Do I have to charge every single one by themself? How do I check them?
          You should not connect them together either for charging or for supplying your loads. That is just a fact of battery life when mixing types, sizes and ages.

          You can start by charging each battery individually (or identical batteries in parallel) to see what they look like when fully charged. Then try loading them down and see what happens. (Again individually or in identical sets in parallel.)
          SunnyBoy 3000 US, 18 BP Solar 175B panels.

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          • #6
            Originally posted by SunEagle View Post
            +1

            I think your answer about the mix of battery types (AGM & FLA) is the issue.

            Also from another of the OP's posts, those 7 batteries have different Ah ratings. My guess is that they have not been charging and discharging equally and now he has one or more of those batteries going bad.
            This is from the other post the OP posted.
            I have 3 yellow top AGM deep Cycle (75ah each), 2 walmart marines batteries 114ah each and 2 AGM Small batteries 35ah each.

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            • #7
              ...I have 3 yellow top AGM deep Cycle (75ah each), 2 walmart marines batteries 114ah each and 2 AGM Small batteries 35ah each.
              BZZZZZ end of game. These batteries are all very different, and need different charge regimes. I'd consider them toasted.

              If your solar is enough to match your loads (you need to harvest 2x the wattage you consume) you should probably try two, 6V-200Ah golf cart batteries wired in series to make a 12V 200ah battery. The batteries are cheap, and in a few days, voltage readings should tell you if you have enough solar to serve your needs.

              Additionally, you have a pretty large inverter, which will consume (waste) a lot of power driving your small loads. Something like a 300w Suresine inverter may be a better match. You have to read the stickies in the Off Grid section:
              http://www.solarpaneltalk.com/forumd...-panel-systems
              Last edited by Mike90250; 01-06-2015, 07:42 PM.
              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


              • #8
                Originally posted by Johann View Post
                This is from the other post the OP posted.
                I have 3 yellow top AGM deep Cycle (75ah each), 2 walmart marines batteries 114ah each and 2 AGM Small batteries 35ah each.
                Thanks for finding that info.

                What the OP doesn't understand is that even though all of those batteries are 12volts you can't charge them together at the same time. Each has different charging (or feeding) needs.

                Similarly would be a family of 7 kids. 2 x teenagers (114Ah), 3 at 11 years (75Ah) and 2 x 5 year old (35Ah). Try feeding them all the same size meal of 2500 calories a day and then have them all do the same amount of physical work. Not going to happen.

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                • #9
                  Originally posted by Johann View Post
                  This is from the other post the OP posted.
                  I have 3 yellow top AGM deep Cycle (75ah each), 2 walmart marines batteries 114ah each and 2 AGM Small batteries 35ah each.
                  And all of them likely dead by now.
                  MSEE, PE

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                  • #10
                    Originally posted by Sunking View Post
                    And all of them likely dead by now.
                    The kids or the batteries?
                    Solar Queen
                    altE Store

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                    • #11
                      Take EITHER the 3 yellow top AGM deep Cycle (75ah each) OR the 2 walmart marines batteries 114ah in parallel and try charging them without all of the mismatched ones. See if you are able to get them to charge and hold a charge. Hopefully at least one of the sets didn't get too damaged from having the others in parallel.
                      Solar Queen
                      altE Store

                      Comment


                      • #12
                        Originally posted by Amy@altE View Post
                        The kids or the batteries?
                        Both I would guess. Most likely he has one of more batteries with a shorted cell and thus drained all his batteries to death. That is why you do not parallel batteries.
                        MSEE, PE

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                        • #13
                          That is why you do not parallel batteries? So can you explain to me how to do it please?

                          Comment


                          • #14
                            Originally posted by zuliwito View Post
                            That is why you do not parallel batteries? So can you explain to me how to do it please?
                            You don't. It's like driving with your foot on the clutch, it never fully engages, just 97% engaged 3% slippage. So you don't rest your foot on the clutch. You don't parallel batteries. Don't spit into the wind.
                            Just suggestions, you can do it if you want, but it's not the best way.

                            regarding batteries, you purchase lower voltage cells with higher amp capacities.
                            12V 100ah
                            or
                            2, 6V 200ah
                            or
                            3, 4V, 400ah
                            or
                            6, 2V 600ah. Keep adding the batteries in series to get the voltage you need. You can get 1,000 ah cells @ 2V from the big vendors.
                            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


                            • #15
                              Originally posted by zuliwito View Post
                              That is why you do not parallel batteries? So can you explain to me how to do it please?
                              Simple if you need 500 AH batteries, buy 500 AH batteries.

                              You are stuck in the 12 volt Twilight Zone box having a bad trip. Get out of the 12 volt box you are trapped in. That is why they make 2, 4, 6, and 8 volt batteries.
                              MSEE, PE

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