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  • Need help!

    Hello!

    I have an 80 watt solar panel with 10 amp regulator and a 119 amp hr battery.

    I purchased an aerator for a pond and was told it was 12v. I checked the manual and said 120 AC and 12v DC and 25 w consumption. Great ...i thought.

    It comes with a transformer and on that it shows output 12v 2.5A 30VA
    On the air pump itself it has a sticker and that shows PRIM. AC 120 V / 60 Hz Sec. AC 12V / 60 hz Pmax 25W
    ================================================== ================================================== ==================

    I tried just out of curiosity to run it on 12v solar battery, nothing happened. I hooked up an inverter and that made it work though i feel not as strong as when i plug it to the mains. Maybe that is because the inverter has a modified sine wave?

    1) So what do i do here? I mean it says 25 W and 2.5 A but based on values of the transformer that comes with it, i believe this thing uses more like 75 Watts and 5 amps?

    2) Is their such a thing that can convert 12v DC to 12v AC? I find it a waste to go from 12vd to 120 Ac and back down to 12v Ac

    3) If i get an inverter, probably only option will i be fine with a 100 or 150 Watt inverter? I found some but then i see it states 0.9 Amps 100w max continuous. Even a 500 watt inverter also mentioned 0,9Amps. How is that going to work if i need 2.5 A or more?


    I plan to run it only in daytime or only at night and charge in daytime not sure which would be better. Assuming 25Watt i can use it in daytime but if it is more like 75 then ibetter just use it at night a few hours.









  • #2
    sales men will never lie.
    except in your case. It's likely the pump is an AC only pump, and you are lucky it's still working after connecting to the battery, Till I have accurate info, I can't advise.
    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
      Makes sense. but in regards to inverters on the market.

      They state 0.9 Amps 100w max continuous. Even a 500 watt inverter also mentioned 0,9Amps. How is that going to work if i need 2.5 A or more? Can someone explain that ?

      Comment


      • #4
        Originally posted by samkat View Post
        Makes sense. but in regards to inverters on the market.

        They state 0.9 Amps 100w max continuous. Even a 500 watt inverter also mentioned 0,9Amps. How is that going to work if i need 2.5 A or more? Can someone explain that ?
        You are getting your amp requirements confused. The 2.5amps is the rating of the transformer output at 12volts which calculates to 30VA or 30watts.

        The inverter has a rating of 0.9amps at 120volts which calculates to ~ 108VA or 100watts.

        That aerator pump is rated 25watts which at 12volts will draw ~ 2.1 amps or at 120volts draw ~ 0.21amps.

        Comment


        • #5
          awesome! thank you for that! Learned something new today

          Comment


          • #6
            Went and got an inverter 150w that plugs in car lighter. I think it's faulty cause it would go on and of on and off battery is good

            Comment


            • #7
              Originally posted by samkat View Post
              Went and got an inverter 150w that plugs in car lighter. I think it's faulty cause it would go on and of on and off battery is good
              Yeah that does sound like a bad inverter. I have a 250 watt one that I keep in my truck just in case I need to power something that requires AC.

              Comment


              • #8
                Originally posted by samkat View Post
                Went and got an inverter 150w that plugs in car lighter. I think it's faulty cause it would go on and of on and off battery is good
                Was that a quick test from your own running vehicle's cigarette lighter, or was it attached to your 119ah battery when it would cycle on and off?

                I suspect your battery is actually not good, and even the mere 2.5 - 3A draw from the inverter is pulling it down to the dead-man low-voltage-disconnect switch level of 11.7 or maybe 10.7v. Is it doing that?

                Ideally, for a 119ah battery, you should try to run close to about 0.1C, which would mean doubling your panel power at the minimum for flooded. That 80w panel is only supplying a measly 4.5A under the best of conditions, (about .05C) and now that we are in winter-time hours, that is not enough to fully charge the battery from any significant amount of discharge.

                So here come the battery questions:

                New or used? Brand and model helps too to determine if your CC voltages are set up properly.
                Flooded or AGM? (or other)
                Has it *ever* seen a full charge from an ac charger?

                Comment


                • #9
                  First i tried on the deep cycle 119 ah battery (National brand here LTH) and then i went out to the car and hooked it up to the car battery and had the same issue. I am in Mexico so the sun in my town is not an issue. It is sunny most the year and rarely cloudy. I can count the days i dont use the A/C in my home too lol. Most probably i will run it during the day or during the night a few hours.

                  I will go buy another inverter and have a queestion. If i get a bigger one, will it get less hot when running an appliance that i can easily run on smaller inverter?? If yes, i will go with a bigger one but really i just need it with one outlet but at the same time if a larger one will be more efficient than i might get a bigger one instead.

                  Comment


                  • #10
                    Actually larger inverters are usually less efficient then smaller ones.

                    Comment


                    • #11
                      You are right! I was reading on forums and came to the same conclusion

                      Comment


                      • #12
                        I have a number of inverters and when I had to run my CPAP machine all night I tried a couple of small inverters. Contrary to belief the 400W unit drew less idle current than a 200W unit. Idle overhead power is about 3W with no current draw with the fans removed. Fans draw a lot and are not needed in that power range. A CPAP is 25W so this comparable with your operation. I run a 200W with no fans on my fridge. Startup currents with motors are significant. That 130W fridge actually draws 120A from the inverter at startup. Your inverter could be going into current limit. On MSW motors usually draw a little higher current. I haven't bothered in my application, but on some older inverters the on time can be shortened for lower power consumption.

                        Comment


                        • #13
                          Originally posted by PNPmacnab View Post
                          I have a number of inverters and when I had to run my CPAP machine all night I tried a couple of small inverters. Contrary to belief the 400W unit drew less idle current than a 200W unit. Idle overhead power is about 3W with no current draw with the fans removed. Fans draw a lot and are not needed in that power range. A CPAP is 25W so this comparable with your operation. I run a 200W with no fans on my fridge. Startup currents with motors are significant. That 130W fridge actually draws 120A from the inverter at startup. Your inverter could be going into current limit. On MSW motors usually draw a little higher current. I haven't bothered in my application, but on some older inverters the on time can be shortened for lower power consumption.
                          I won't argue the point that some larger inverters can be more efficient then others. In general the larger they are the more they burn watts just sitting there without any loads connected. It all depends on the make and model as well as the quality and where they come from.

                          IMO the cheaper they are the lower the efficiency they are rated.

                          Comment


                          • #14
                            The issue with that inverter was without connecting any load so definetly something wacky with it.

                            Comment


                            • #15
                              I just tried a new RIDGID 100W inverter and that drew .41A @13V or 5.3W with no load. It is my experience that these really small inverters by the nature of their design are inefficient. The real problem is the cigarette lighter socket which is notorious for poor connections. Have you tried connecting it up to a battery directly?

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