Eco Solar refrigerator help

Steph09872002Steph09872002 Registered Users Posts: 5 ✭✭
Hi All!

I have an upright Eco solar refrigerator (https://www.ecosolarcool.com/product...cuft-escr355ge) It is having a hard time staying cool. I have contacted the company but they haven't been much help. I will post the whole system and if you have any advice on the issue that would be great! Thanks in advance
12Awg 6 foot cable going from the fridge to the batteries 2 Duracell Ultra 6V Deep Cycle Golf Cart Battery
SLIGC115. The battery bank has a 10 awg cable going to the charge controller (Blue Solar 12/24v 50a mppt 100/50). Going to solar panel (solar world sumodule sw 320 xl mono)

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,800 admin
    Your fridge takes a maximum of 96 Watts (starting?)... Figure the voltage drop for 12 AWG 6 feet of cable:
    • 96 Watts / 10.5 battery cutoff voltage = 9.1 amps
    https://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=5.211&voltage=12&phase=dc&noofconductor=1&distance=6&distanceunit=feet&amperes=9.1&x=70&y=20

    Voltage drop: 0.17
    Voltage drop percentage: 1.45%
    Voltage at the end: 11.83

    So... Voltage drop of 0.17 volts sounds OK.

    Regarding your system, what is the battery terminal voltage (under load, I would suggest >~11.5 volts)? And the voltage on the refrigerator should be >~10.5 volts.

    Assuming worst case draw of 9.1 amps continuous, and a ~200 AH @ 12 volt battery bank, draw down to 50% state of charge (suggested for longer battery life on solar charging), that would give you a "useful" battery life (full charge to 50%) of:
    • 200 AH * 0.50 discharge * 1/9.1 amps = ~11 hours minimum battery usage (assuming fridge running full time--I.e., Warm food/ice making)
    The typical usage is 0.6 kWH per day:
    • 600 WH / 24 hours per day = 25 Watt average usage
    • 25 Watts / 10.5 volts = 2.4 Amps average load
    • 200 AH * 0.50 max discharge * 1/2.4 amp ave load = 42 hours (fully charge battery bank, cold fridge/freezer, ave room temp, to 50% battery bank capacity)
    Assuming all of the above is "OK" electrically and you have good airflow and clean condenser coils on the fridge, what are the exact problems you are having? Not getting cold in fridge, freezer not freezing, icing up, too much condensation, etc.?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Steph09872002Steph09872002 Registered Users Posts: 5 ✭✭
    HI Bill,
    Thank you for responding. The problem that we are having is that the fridge isn't staying cold. It will get down to 39 but fluctuates between 39 and 59...The batteries at the terminal get down to 10.5 overnight....
  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    At 10.5v, the batteries are essentially dead. I don't recall the cutoff voltage on the Danfoss compressor, but it will be almost certainly be shutting itself off at that voltage.

    How old are the batteries?
    Were the batteries fully charged the evening before?
    Are there any other loads on the batteries?
    Do you have a hydrometer to check specific gravity of the battery acid?
    What is the approximate ambient temp?
    Was any warmish food added to the fridge?
    Is the door sealing well?
    Is there good airflow to & from the compressor?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    As an experiment, if possible of course, use a fully charged battery to see if the refrigerator works, it may well be the battery is unable to start the compressor, especially when depleted, 39°F is normal, or 4°C for the rest of the world. Using a timed inverter block for 4 hours overnight, I discovered the temperature in the morning was at a very similar to the value of 59°F/ 15°C, it's amazing how much it changes over a short period of time. Additionally if the battery has been subject to such low states of charge over an extended period, the capacity will, in all likelihood, have been reduced. The use of a much larger capacity battery may be all that is required,  naturally the charging needs to be able to replenish what's taken out, plus losses roughly ~125%.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    The danfoss doesn't have particularly high startup demands, and should run fine on a pair of GC in decent shape, at least as low as ~40%SOC. I haven't tried it any lower on the boat.

    Trying a known good battery or pair of GCs would help establish if the problem is the battery or the fridge/environment.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators, Administrators Posts: 32,800 admin
    It sounds like either bad batteries or they are not getting properly charged. Your batteries are being drained to dead overnight--Which should not happen with a properly running fridge...

    What is your charging system like (if solar what brand/model of solar panels, array configuration, brand & model of charger controller, wiring, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    BTW, if the compressor is similar to mine (I have 3), it has a quite small, fan cooled condenser coil. Unlike a typical fridge, which has a large coil at back and/or large surface area skin cooling, it wouldn't take much of a blockage to severely impair efficiency.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Steph09872002Steph09872002 Registered Users Posts: 5 ✭✭
    Thank you all for the responses. I didn't get any notifications that there were any and I haven't had a chance to check. So the batteries were brand new just about a month ago. When I purchased the fridge in January I bought a brand new 12v battery which was killed by the fridge....They are getting fully charged during the day...We just went away for a week, noone home to use the fridge, and when we arrived home the fridge was only down to 45 degrees. I have a 50 amp mppt charge controller, the company says that it needs a 15 amp...Wouldn't it be fine if the charge controller were larger then required? With my solar panel being 320 watts I don't think a 15 amp charge controller would be big enough...ugh.,wasting so much food.
    There is no other load on this little system..
  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    Using a larger charge controller should be fine. In ideal-ish conditions, the 320w panel might be good for 20-25a into the battery, so better to have a controller that will do it. 20a is a good charge rate for a pair of GC batteries.

    Are you certain the batteries are getting fully charged during the day)? One thing to check is the voltage at the charge controller output, and at the battery +/- terminals, when charging at a good (20a) rate. The battery terminals shouldn't be more than about 1/10th volt lower. Ideally, specific gravity should be measured to confirm full charging. Water should also be checked regularly.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    Also, is there any chance the panel could be even partly shaded (nearby wires, plumbing vents, etc) anytime between ~10am-3pm?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Steph09872002Steph09872002 Registered Users Posts: 5 ✭✭
    Ill check that tomorrow. I have only ever checked the voltage at the terminal. Our panel does get some shade during those hours
  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    Depending on the nature and orientation of the shading, it could cut output to near nothing.

    Does the charge controller have any diagnostic info (like kw hours produced daily)?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Steph09872002Steph09872002 Registered Users Posts: 5 ✭✭
    No it doesn't...Can I check the panel with a volt meter?
  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    You can, but it likely won't tell you much. Open circuit voltage will be close to spec with pretty low light.

    A clamp-on DC amp meter, or a permanently installed meter (ideally shunt based) would tell you what current is being produced. Absent that, maybe check battery voltage first thing in the morning, and see how long it takes to get to the controller absorb setting (~14.5v). It should take ~1hr per 10% state ofcharge under ~90%, so at 50%SOC, it should take ~4-5 hrs to get to absorb setting. From 70%, it should take 2-3hrs. If it takes a much shorter time, the batteries may be damaged. If it takes a much longer time (or never gets there), either the fridge is taking too much of available current, or the panel isn't producing enough, or some combination of both.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • bill von novakbill von novak Solar Expert Posts: 891 ✭✭✭✭
    HI Bill,
    Thank you for responding. The problem that we are having is that the fridge isn't staying cold. It will get down to 39 but fluctuates between 39 and 59...The batteries at the terminal get down to 10.5 overnight....
    Then your batteries are dead.

    1) Replace batteries.
    2) Ensure they are getting enough charge.  A battery monitor (like a Trimetric) would tell you for sure.  If not, cheaper options (like a Wattmeter from Powerwerx) are available.
  • NANOcontrolNANOcontrol Registered Users Posts: 229 ✭✭✭
    Refrigeration systems are real battery killers. You just think you have enough panels to recover. It is a downward death spiral once you can't recover.  My fridge in active use requires about 450WH and it takes me 2,500W of panels to insure the fridge will operate every day. Sometimes things just aren't ideal. I have to laugh at these youtube videos that say a fridge can operate on a 100W panel. You need a low voltage disconnect with a time delay that will turn off the fridge at 12.4V.
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