How much power does your fridge use?

Matt

In the scheme of things i.e. 'Life, the Universe and Everything'....does it matter?


LOL!


Cheers

Hi Matt

The physics of fridges indicate that bigger fridges use proportionally less power.

I.E. a 50lt fridge doesn't not use twice as much as a 25Lt , this is because volumne increases at a greater rate than surface area.


P.S. My own little CF25 uses approx 18AH per day

We have a Waeco 220 litre fridge / freezer and my observations says that it uses between 40 and 50 amp hrs each 24 hours. I have packed insulation around the outside of the fridge which I believe dropped the top end down to 50 from 60 amp hours.
I have installed a shunt to accuately measure my power consumption as I run mostly on solar power.


Neil

I have a Waeco 40 litre which wa sin the car last weekend in the 38 degree heat. Some days it didn;t cool down until 10.00 at night.

I covered the windows as much as possible on the sunny side and left the windows open a couple of cm to allow some air circulation.

Nothing was put in it, I opened it a couple of times a day to take things out.

It used 5 amphours at night and 20 amphours during the day !

We have a waeco CF50 and when running it uses 3.6 Amps - so I'd guess at 32 - 40 AH per day - Although after 3 days of 36 plus near Mt Isa we got the battery 100aH battery down to 50% even with an 80 watt panel - But the fridge was in the back of the Jeep in 50 plus degrees ..

Rgds

Mandrake

G'day Matt

If you can get hold of a copy, have a look at Collyn Rivers The Camper Trailer Book Chapter 10, also chapters 6-9. He also has some related stuff on www.campertrailers.org. at the end of Tech Tips.

I live in Macgregor ACT, so if all else fails, you can borrow my copy. I read it, sometimes I understand it, I don't do advice!

Cheers
John

I've had my 'power hungry' liemack 50 Lt f/f independently tested by the 12v shop in Perth over a period of 3 days, 2.8 ah.

My newer Reefer 70 Lt f/f runs a bit more efficiently even thought it draws ~10 Amps max.

Maîneÿ . . .

Out of interest Matt what device do you use to measure amps over time?
Everyone's results of course can be nothing but different depending vastly on the exact temp the fridge is set at, the number of times it's opened. the amount of warm food put in to be chilled & of course the ambient temperature. Your best & worst figures being over 150% different I think confirms this.
Cheers Craig............

5+ years of running the Waeco 80 lt, freezer at max =-18c + fridge section = 2 /4 c and dairy at 7/8c .. power avg @ 64amp hrs per 24hrs , 15lt Engle over same time frame yrs set at constant 2deg c =42amp hrs per 24hrs , Ambient temp variations over 5yrs use from -5c to +55c .

Hi Matt, 4WD Action did a fridge comparo a few issues back which included power consumption. http://www.4wdmonthly.com.au/tips_fridge.php

TJ...

I am intrigued how people are measuring or determining the ampere-hour consumption of their fridges.

Do you have ampere-hour meters connected?

Or do you have ammeters connected which log at frequent intervals to your computer and integrate the readings?

Or are you observing the amps and keeping careful record of running time over the 24 hour period?

All of the expressions are in unqualified expressions of ampere-hours not expressed as "approximately" or as a single instantaneous reading extrapolated out to 24 hours.

How on earth do you determine these explicit ampere-hour figures?

We run an Engel 60L as a fridge (15 deg) .........Using the PL20 readouts we average around 80 ah in 24 hours.......that is in ambients of low to mid 30's C

cheers

Waeco cf50verb set at 2 degrees opened approx once per hour .
On fridge slide in bag in trayback ute under aluminium roof and canvas sided canopy in Brisbane late spring as recorded by current measuring datalogger.

Usage about 25Ah per day.

Testing done to ascertain size of required solar capability.

And i thought the Overclockers forum was full of geeks.

are you all single?

now fancy that!!

Good Morning all,

After a good night's sleep I reconsidered Matt's original question...............

"How much power does your fridge use?"

Does it really matter in the vast scheme of things?

You already own the damn thing.
You already have an energy source for it.
Does it keep the beer cold?

That's it. End of story.

The only value I can see in comparing the numerical energy consumption of fridges is to determine their relative value before purchase. And any such comparison would need to be performed under identical operating conditions. Not independent field conditions.

So I am led to ask you Matt.......... Why did you ask the original question? And did the responses satisfy?

I have a 60ltr Waeco that runs at 0deg ( ice just forming on top of beer sometimes ) and it runs off 6 batts in the KK ( but lives in the rear of the 4wd )..

After a 4 day weekend ( say 32deg ) the batts are down to approx 12.1V....so when I get home I whack them back on charge....

I don't give a rats what the a/h's are, because the setup I've got is what I've got and apart from adding solar, ain't gonna change, so apart from glancing at the voltmeter a couple of times a day, I usually do what I went camping for.....relaxing ( and maybe with a coldie in my hand ).......

OK Mainey, I'll give this one last shot.............

Please do try to master the difference between Amperes (A) and Ampere-hours (Ah)

Clearly the 12Volt Shop tested your fridge over a period of 3 days and reported that its effective averaged running current was 2.8 Amps. If in fact it was running at 33% duty cycle (that is running for a third of the time, say 1 minute on and 2 minutes off) then when actually running it would be drawing 8.4 Amps (2.8 X 3)

But regardless of the numbers, clearly the reported 2.8 refers to Amps NOT Amp -hours. Sure, if it is runs at an effective 2.8 Amps for an hour then it will have consumed 2.8 Ampere-hours, or if it runs for 2 hours it will have consumed 5.6 Ampere-hours and so on.

But just consider what you have said..... "the fridge was independently tested over a period of 3 days with the end result being 2.8 AmpHour consumption, definitely not 2.8 Amps". If it was only "2.8 AmpHour consumption" in a 3 day period then you could run that fridge on a handful of AA alkaline batteries.

With your solar/battery setup you MUST be aware that your fridge is going to consume a helluva lot more than 2.8 Amp-hours if it runs for 3 days, otherwise you would hardly need your 200watt solar and 2x 100Ah batteries unless you have some helluva other loads.

Now honestly, I'm not trying to arm-wrestle you. I really would like you to fully grasp the meanings of Amps and Ampere-hours and if what I have explained does not do it then to go on would be simply futile.

All the best mate.

To record Amphours I use a WattsUp Meter - keeps a record of everything including Maximum Current/Power, Minimum Voltage etc.

It goes in line between Battery and Load using Anderson 30 Amp Powerpoles

Me thinks some of you guys have way to much time on your hands, My waeco 110 uses about 4.8 amp when running, it runs about 50% of the time in cool weather, and about 90 - 100% of the time in the hot weather which equates to a heap of power, 120 amps +, I feed it and everything else with 400ah's of batteries, I monitor it all on a digi volt metre, and when it gets down a bit i charge it up, thinks thats as technical as I need to get.

But hell i need one of these "incllement ozonic stratospheric pressure meters so I can check on my "altilogarihydrocalipro meter , so i can check the power used to drive BOTH my hiclones?

Lighten up guys, when it all comes down to it, we need to keep the snags cold alongside the beer's and wine !

Cheers Pesty

Have run my Explorer DC65 fridge/freezer today with both thermostats set on 5. Thermostats go from 1 warmest to 7 coldest. 5 setting is about as cold as I can take it without risking freezing stuff in the fridge. It took 6.5 hours to draw a spare 24AH battery pack down to the 50% charged state. That is 12.1 volt reading when fridge was cycled off. Ambient temperature today is around 30 degrees. The fridge was running from 240 volt prior to this "test" so all the battery power has just been to maintain the fridge/freezer temperature.

So very roughly, assuming that the battery pack was really 24AH and that it was discharged to the 50% point then about 12 amp hours were used over the 6.5 hours. Now dividing 12 by 6.5 gives 1.85. So on average at 30 degrees using my preferred setting of 5 on the thermostats it uses a little under 2 amps on average.

There are whole heap of assumptions here, granted, but I think the 2 amp figure is relevant for calculations of what sized battery do I need as I am now getting a dual battery setup.

I may repeat this "test" on a thermostat setting of 4 to see if consumption drops much. 4 is probably what I will run it on when vehicle is parked overnight and 5 when on the move.


Flynnie