Whynter refrigerator just about killing my battery after 12 hours

[luthj]

Obviously every fridge model is different, and the load will vary depending on ambient temp. Lower ambient temps mean less compressor head pressure, and lower power usage when running. Also some compressor controllers vary compressor speed depending on cooling load.

0.33A is obviously at 120VAC. Which is about 40W. With a 40W consumption the duty cycle would be about 23% at 224 watt-hours per day.

 

[67cj5]

The setpoint on my fridge and the temperature shown usually are far off. The readout usually shows colder than my wireless thermometer too. I think I had the fridge set at 37-38 degrees when I was getting those 33-35 degree readings. Also, Whynter shows their ratings at 77 degrees ambient and it was more like 65 degrees for my testing.

One thing to remember when testing these fridges is try not to put jugs of water etc on top of the thermistor or the fridge won't shut off until the fridge has cooled down that Item, always place them either side of the thermistor then it will cycle and slowly cool what is ever in there.

 

[luthj]

The setpoint on my fridge and the temperature shown usually are far off. The readout usually shows colder than my wireless thermometer too. I think I had the fridge set at 37-38 degrees when I was getting those 33-35 degree readings. Also, Whynter shows their ratings at 77 degrees ambient and it was more like 65 degrees for my testing.

I have put calibrated temp probes in various fridges. Usually the built in sensor (if equipped) is off by plus/mins 2F. The temp inside the fridge will usually vary plus/mins 5f across the fridge depending on contents and measurement location. Not really that bad, as even industrial/commercial units can have similar variances.

Adding a small fan to circulate air inside the fridge often does a great job of evening out temps, and lengthening cycles.

 

[67cj5]

Obviously every fridge model is different, and the load will vary depending on ambient temp. Lower ambient temps mean less compressor head pressure, and lower power usage when running. Also some compressor controllers vary compressor speed depending on cooling load.

0.33A is obviously at 120VAC. Which is about 40W. With a 40W consumption the duty cycle would be about 23% at 224 watt-hours per day.

mine runs on 240v, same as back home in Oz.

 

[luthj]

mine runs on 240v, same as back home in Oz.

okay, thats 80W then (0.33 x 240V). Which means you probably have a fair bit of inefficiency in the AC-DC power brick (most DC fridges use one when on AC power). Though some fridges actually ramp up compressor speed when on AC power, as they are not worried about battery efficiency.

 

[67cj5]

It never uses 80w, I have it plugged in to a power meter, It's peak Spike is 56.4w and it's low reading is 4.4w.

 

[luthj]

It never uses 80w, I have it plugged in to a power meter, It's peak Spike is 56.4w and it's low reading is 4.4w.

Then it can't be using 0.33A at 240VAC. 56W is 0.2A at 240VAC, or 2.5A at 12.5VDC.

 

[john61ct]

Watts just like amps are an instantaneous unit of energy flow rate.

Watts per hour makes zero sense.

Watt hours and amp hours are required talking about quantities of power.

So using 1.5kWh per day makes sense, half an AH per hour makes sense.

A 60W constant load running for six hours uses 360 watt hours.

If the cycling rate is 30% that's around 120 wH, extrapolated over 24 hours 480wH per day.

At 12V, those are 5A, 30AH, 10AH and 40AH, respectively.

Watts or amps per day, is just nonsensical.

 

[john61ct]

To measure off, grid consumption, put a totalizing AH counter on the appliance for 24hrs and measure directly.

Measuring watts directly the trying to extrapolate from a cycle rate will never be accurate

 

[67cj5]

Then it can't be using 0.33A at 240VAC. 56W is 0.2A at 240VAC, or 2.5A at 12.5VDC.

Of coarse it will be accurate when cross checked with 3 or 4 other meters they can't all be wrong when they all read the same figures., anything that has a 4 digit or higher should be accurate enough for these simple tests.
Well those are the figures that are on the screen of the meter and All 3 meters have been cross checked. And in real world testing all ARB fridges display extremely low power usage, using around 9 amps or less in 15hr+ period, like it or not those are the facts,

So far in 64.633 hours / 64h 38minutes my fridge has used 667watts running on240v AC, In one of those pictures you will see that it has used 670watts in over 2 days 17 hours and 13 minutes, that's is 65.216 hrs, So that's 670 divided by 65.216 = 10.2735525024 watts per hour. And the watts and Amps picture are the Peak readings not the average readings

here are 2 videos proving the same.

 

[john61ct]

in real world testing all ARB fridges display extremely low power usage, using around 9 amps or less in 15hr+ period

If what you mean is 9aH, that must be in pretty ideal conditions? Also ambient not too high, target temp not too low?

 

[67cj5]

If what you mean is 9aH, that must be in pretty ideal conditions? Also ambient not too high, target temp not too low?

That test was done @ 82.4*f / 25*c with the temp set at 3*c / 37.4*f which is high enough to give most fridges a workout, And when tested in Aus prior to release they were tested out in the Desert and still managed to only use 0.87A/H per hour over a 66 hour period.

 

[XPTom]

"Yours can't be using 65w because that is the per hour rating, 65w divide 60 minutes = 1.08333333333 watts per minute, If it runs for 14m 18 seconds, that's a total of 15.491666666watts per hour ….."

In no way, shape, or form is a Watt an AMOUNT of energy. It is an instantaneous RATE of use, that when multiplied by hours gives watthours(amount) consumed . If you drove at a rate of 60mph for 10 hours you would travel 600 miles. It would not be correct to divide 60mph by 10hours and then do a bunch of extra math to make sense of the 6mph number. In modest temps my 65W cooler runs 8 or so hours.... approx. 520 watthours.... within the limits of my 70AH battery. In the Nevada desert it runs 20 hours plus.... 1100++ watthours.... the battery doesn't have a chance.

 

[67cj5]

"Yours can't be using 65w because that is the per hour rating, 65w divide 60 minutes = 1.08333333333 watts per minute, If it runs for 14m 18 seconds, that's a total of 15.491666666watts per hour ….."

In no way, shape, or form is a Watt an AMOUNT of energy. It is an instantaneous RATE of use, that when multiplied by hours gives watthours(amount) consumed . If you drove at a rate of 60mph for 10 hours you would travel 600 miles. It would not be correct to divide 60mph by 10hours and then do a bunch of extra math to make sense of the 6mph number. In modest temps my 65W cooler runs 8 or so hours.... approx. 520 watthours.... within the limits of my 70AH battery. In the Nevada desert it runs 20 hours plus.... 1100++ watthours.... the battery doesn't have a chance.

If you look at those meter pictures In the 3rd Pic you will see that at the top it says 17h 13 mins, in the middle screen it says 0.670KWH and in the lower screen it says 2 Days which is 48 hours + the 17h 13m = 65h 13 . Divide the 0.670KWH or 670watts by 65.216h = 10.2735525024 being the Average watts per hour

And you have "your" formula Wrong You don't divide the 60mph by the Hours you divide the hours by the 60mph, As I did dividing the watts by the hours..

Say what you like but the fact remains that it still only consumed 670 watts of power over a period of 65+ Hours, The meter can't lie. And I have left it plugged in and it is still recording the power usage Now 5 days later.

The Electricity company charges me by the watts used Not the Amps, So it must reflect the power used or they would not have a clue on what my power bill is when they send me a bill that needs to be paid.

 

[67cj5]

Its actually billed by watt hours,
Or more properly kilowatt hours (kWh) whats not the same thing as “watts”.

There are 1000 watts in a Kilo Watt and it is still the same measurement because if that were not the case then at 670watts my fridge would have used 43694.72 watts in under 3 days which is ridiculous because at the end of the year that would be 5,869,200 watts.

Like it or not that meter is displaying the power used, and by testing all of the items in my home I have reduced my power bill by 2/3rds.