Please help me understand this!

bdannels
bdannels Registered Users Posts: 9
I have 2 – 140w 12 volt panels connected to a BlueSky 2000 25 Amp. Controller.
They are in turn connected to 2 –(New)Duracell EGC2 Golf Car Battery - Group Size 230
20 amp hour rate:230 1500w PowerMate inverter.

I am trying to power a Dometic RM-2652 Gas/Eletric Frig. Frig specs. Says it draws 2.75 amps.
I plugged the Frig into the inverter at 12:00 noon, Frig has been running for 1 ½ days on propane.
50-60% cloud coverage, controller says 12.9 volts/10.5 amps out. I have a Kill-a-Watt meter between the Frig. and Inverter showing 324 Watts. 2.7 Amp draw.

Taking random time samples whenever I checked the controller listed below.
Volts Amps. Time
12.41v 11.0a 12:04
12.20v 11.5a 12:10
12.52v 11.1a 12:41
12.17v 11.6a 1:00
11.90v 3.5a 1:08
11.96v 10.9a 1:39
11.87v 10.6a 2:11

When I unplugged the Frig. The Bat. Volts went back up to 12.09 in about 30 seconds. At about 1 minute the bat. Was at 12.16v 7.8amps. I quit looking after that.

I know you need to put more amps in to maintain battery level, BUT this to me is showing I am putting
about 4 times what I am using AND the battery level is still going down fast?

Comments

  • AuricTech
    AuricTech Solar Expert Posts: 140 ✭✭
    Re: Please help me understand this!

    If the Kill-A-Watt is reading 324 watts @2.7 amps, that gives you a voltage of 120 volts (324W / 2.7a = 120V). Which means that you're actually drawing about 27 amps from your battery bank.

    Are you sure your fridge isn't running on AC power?

    ETA: Looking at the owner's manual, I see on page 4 that there's an automatic energy selector system that defaults to 120VAC. Is "AUTO" set to "OFF"?

    ETA2: Re-reading your post, if you have the fridge plugged into the inverter, you're definitely running on 120VAC, which explains the power drain. Here's a link to an installation guide. On page 10, it discusses how and where to make your DC connection to run the controls. Hope this helps!
  • Plowman
    Plowman Solar Expert Posts: 203 ✭✭✭✭✭
    Re: Please help me understand this!

    Yep, looks like you're running the fridge on AC. You shouldn't have it plugged into the inverter, RV fridges need 12V when run off propane. My RV fridge draws a maximum of 0.3 amps @ 12V when running on propane---this just powers the controller. When plugged into AC it draws 200+ Watts @ 120V (massive energy hog when run on AC).
  • bdannels
    bdannels Registered Users Posts: 9
    Re: Please help me understand this!

    >Hope this helps!

    It's shows me I still have a lot to learn, that's for sure!
    I was thinking 2.7 amps was 2.7 amps, not paying any attention to the volts. My son has a 4.2 cu ft frig that he runs with a inverter, NO solar for weekend camping. He says 2 Golf cart batteries will run it all weekend!

    Not addressing it will kill the batteries with no charging, I thought I could do the same with my frig and save the gas for cooking and charge the batteries.
    maybe the smaller frig. draws less amps than my Gas/Eletric. I do see where it will NOT run off 12 volts.

    Really appreciate your input

    Tks.
    Bill
    AuricTech wrote: »
    If the Kill-A-Watt is reading 324 watts @2.7 amps, that gives you a voltage of 120 volts (324W / 2.7a = 120V). Which means that you're actually drawing about 27 amps from your battery bank.

    Are you sure your fridge isn't running on AC power?

    ETA: Looking at the owner's manual, I see on page 4 that there's an automatic energy selector system that defaults to 120VAC. Is "AUTO" set to "OFF"?

    ETA2: Re-reading your post, if you have the fridge plugged into the inverter, you're definitely running on 120VAC, which explains the power drain. Here's a link to an installation guide. On page 10, it discusses how and where to make your DC connection to run the controls. Hope this helps!
  • AuricTech
    AuricTech Solar Expert Posts: 140 ✭✭
    Re: Please help me understand this!

    The problem with an RV 2-way or 3-way refrigerator is that it's an absorption refrigerator, which means that it uses a heat source to drive the cooling cycle. Unfortunately, using electricity to generate heat is about the most wasteful thing you can do with electricity. It's not a problem in RV parks, where shore power is generally available. Off-grid, you're better off using one of these options:
    • Run your absorption refrigerator on propane
    • Buy an EnergyStar-rated electric refrigerator (compressor refrigerator)
    • Buy a DC-powered compressor refrigerator specifically designed for off-grid use (such as the SunDanzer line of refrigerators and freezers)

    Your son's small refrigerator is almost certainly a compressor refrigerator, though probably not one optimized for maximum efficiency.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: Please help me understand this!
    AuricTech wrote: »
    r is almost certainly a compressor refrigerator, though probably not one optimized for maximum efficiency.

    And as many of us here have tested/proved, it is very likely your son's little 4cf fridge (even if brand new) uses as much, if not more, power than a new full sized 18cf energy efficient fridge. The small units are horrible.
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