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    New to all this, I have (4) 6 volt batteries hooked in series, giving me (1) 24v , 235 aH system. I have a 30 amp charge controller, (2) 250 watt, 8 amp panels, and a 24v 3000 watt inverter. I am only trying to run (1) refrigerator that I believe only draws 1.8 amps. Should I be able to run this frig. 24/7? My bank seems to drain most days, what have I done wrong? Thanks for any inside provided,, Mark
    Last edited by Mark1114; 09-24-2016, 12:30 PM.

  • #2
    3000 watt inverter is too big for 24v. It may only draw 1.8 amps at 117v that's over 200 watts. is that continuous? most AC powered refrigeration units are not well insulated and front load refrigeration from battery comes at a huge cost. If you are serious about this off grid refrigerator, I highly recommend investing in a top load 24volt DC native refrigerators. There are many brands, Dometic and Norcold for example. that would run on your current set up with power to spare. Refrigeration is a demanding load. with an outrageously oversized inverter you are killing your batteries. I hope you have terminal fuses. You likely need more solar but there are other unknowns, are all your connections tight and secure? what size wires from array and to inverter. you need to turn off that inverter and get those batteries on a good stiff charge b4 they are boat anchors

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    • #3
      I have even tried (4) 250 watt panel is parallel, to no luck, I do have a 12v inverter as well, I will switch to that. I am using 2 ga. battery connections with fuse, and I will look into DC frigs, Thanks for the reply

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      • #4
        you need to plug the fridge into a meter, and see how much power it consumes. Then you can size the battery bank.
        Newer, Energy Star fridges cost a lot, but are pretty efficient, maybe 1Kwh daily,
        That is barely doable with a 24v 200ah bank (4,800wh) Generally a 1Kw-1.5Kw inverter (pure sine only) is needed to be able to start the compressor, Too small of inverter and it can't start it, too large, you waste a lot of idle power.
        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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        • #5
          Originally posted by Mark1114 View Post
          I believe only draws 1.8 amps. Should I be able to run this frig. 24/7? My bank seems to drain most days, what have I done wrong?
          Pretty simple you guessed and wanted to believe so much, you threw all logic and fact checking out the door. You failed to make even one single simple fact check: How much energy do you need in a day. Your fridge uses a lot more energy than you can generate in a day, or you did a really poor job installing everything.

          Example that 1.8 amps. WTF is that from battery or AC power. If AC power that is 225 watts or 11 amps from the batteries. A 225 watt load should have told you are already in trouble with 500 watt panels.
          MSEE, PE

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          • Mark1114
            Mark1114 commented
            Editing a comment
            Thank you for your input, my meter says the frig uses 1.8 amps when running.

        • #6
          1.8 amps does not tell us a damn thing unless you specify a voltage it is delivered at. No one really caers what the voltage or current is as it does not what we work with. Voltag eand current are just the end results of calculations. Power and Energy are not measured, metered, or billed in Volts or Amps, they are measured in Watts and and billed for how many watt hours you use. 1.8 amps does not mean squat.

          What you did not do is determine how many Watt Hours the Fridge uses in a 24 hour period. It takes about a week to figure that out with a Power Meter by letting it run a week to give you a daily average. Once you have that, then you design a system based on your location, sun exposure, and time of year use.

          Fail to do that and you get 1 of 3 results, and two are bad results.

          1. 95% of people who fail to plan grossly undersized the system as you have done. When they fin dout what it really takes give up and take their losses. Just to expensive when they find out they can buy electricity for 10-cents from th ePower company vs $1 per Kwh making it with solar. Ouch.

          2. 4% Over size and spend to much money. Instead of paying $1-Kwh pay more. Still ouch when you consider you cany buy the power for 10-cents

          3. Actually guessed right. It works but you are still paying 5 to 10 times more for power than you have to.
          Last edited by Sunking; 09-20-2016, 01:25 PM.
          MSEE, PE

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          • Mark1114
            Mark1114 commented
            Editing a comment
            "What you did not do is determine how many Watt Hours the Fridge uses in a 24 hour period. It takes about a week to figure that out with a Power Meter",,,, You could have just said that without the lecture, but based on your number of posts, 241 per month, you obviously like to hear yourself rant at others

        • #7
          With solar, the results are usually pretty disappointing when designing a system to be exactly what's needed. An overbuilt system is a lot more reliable. Solar is an intermittent resource, and loads are variable - so it is hard to design to the minimum or even the average. Just 2 solar panels is not going to do it.
          BSEE, R11, NABCEP, Chevy BoltEV, >3000kW installed

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