LEC 240V fridge power consumption with inverter / power audit

[IanD]

31 minutes ago, blackrose said:

Most of the A rated mini tabletop fridges on Amazon are quoting AC rated current of around 0.45 amps.

 

If I convert that to DC I get the following result which isn't that different from what I'm getting from my "appalling" 3 way fridge run on mains through the inverter. What am I doing wrong? I don't want to get rid of my 3 way fridge and replace it with something that's only going to provide marginal benefits.

 

 

Because all these numbers -- "rated power" -- only show the power when it's running, you don't know how much of the time it runs -- and as was noted above, some of the "3-way" fridges just run continuously so the average power is much higher (don't know if yours does this).

[blackrose]

13 minutes ago, IanD said:

 

Because all these numbers -- "rated power" -- only show the power when it's running, you don't know how much of the time it runs -- and as was noted above, some of the "3-way" fridges just run continuously so the average power is much higher (don't know if yours does this).

 

Ok yes of course. Mine doesn't run all the time on mains, the thermostat switches it on and off.

 

So my point stands. Are the A+ rated tabletop fridges really going to be significantly more energy efficient than my 3 way fridge running on mains? Is mine really that appalling? It doesn't seem like it compared to the table top mains fridges.

Edited September 8, 2022 by blackrose

[blackrose]

2 hours ago, Loddon said:

444410473 LEC L5017 WHI - SPEC SHEET.pdf 35.2 kB · 2 dodownlo

 

Mike: Just another thought if you can live with just a larder fridge the consumption is 2/3 that of one with a freezer box.

 

Thanks Julian. I don't need the freezer box, but your one won't fit into my space because the boat swim is in the way!

[MtB]

2 hours ago, IanD said:

 

Be careful about power consumption, because the classes and test procedures changed -- the LEC uses the 2010 test standard and is rated as A+ (114kWh for 110l), the Liebherr uses the 2019 standard and is rated F (115kWh for 137l). IIRC the test procedure was changed to make it more realistic, which increased reported power consumption as well as changing the ratings...

 

 

That perhaps explains something odd in the world of fridges. I have had occasion to buy several this last few weeks and ALL of 'em are energy rated "F" nowadays. 

 

I eventually found one on Amazon rated "A+" and intrepidly I ordered it. The fridge that arrived, turned up sporting "Energy Efficiency rating F" labels. 

 

 

[Tony Brooks]

43 minutes ago, MtB said:

 

 

That perhaps explains something odd in the world of fridges. I have had occasion to buy several this last few weeks and ALL of 'em are energy rated "F" nowadays. 

 

I eventually found one on Amazon rated "A+" and intrepidly I ordered it. The fridge that arrived, turned up sporting "Energy Efficiency rating F" labels. 

 

 

Blame Brexit, I think. It is the new UK method of domestic equipment rating. I think G is the worst and A the best.

[MtB]

13 minutes ago, Tony Brooks said:

Blame Brexit, I think. It is the new UK method of domestic equipment rating. I think G is the worst and A the best.

 

 

Yes but why are ALL fridges "F" rated now? Not some G or D, or B?

 

You'd think there would be a range of results if they were testing them legitimately.

 

 

[ditchcrawler]

15 minutes ago, MtB said:

 

 

Yes but why are ALL fridges "F" rated now? Not some G or D, or B?

 

You'd think there would be a range of results if they were testing them legitimately.

 

 

They all use the same compressor so its mainly down to insulation, the more insulation the better the fridge the less room for food so they are all basically the same unless you spend a lot of cash

Here are some D which is the best they found 8 Energy Efficient Fridges to Keep It Chill in 2022 - beeco

 

Edited September 8, 2022 by ditchcrawler
I did it again

[IanD]

29 minutes ago, MtB said:

 

 

Yes but why are ALL fridges "F" rated now? Not some G or D, or B?

 

You'd think there would be a range of results if they were testing them legitimately.

 

 

 

Nothing to do with Brexit. Too many fridges were all crammed up in the A/A+/A++/A+++ region, like if everybody got the top grade in exams, so the goalposts were moved so that all the existing fridges were down in the D and lower grades, and the best still only got maybe a C -- to encourage manufacturers to do even better on energy efficiency by trying to push up into the new top grades.

 

Also they don't "all use the same compressor", the better ones use more energy-efficient direct-drive PMAC motors and drives, like washing machines.

Edited September 8, 2022 by IanD

[GUMPY]

30 minutes ago, IanD said:

they don't "all use the same compressor", the better ones use more energy-efficient direct-drive PMAC motors and drives, like washing machines.

There lies a problem of modern fridges with complicated electronics. Not all of them will manage to bring the inverter out of standby mode when needed so the inverter has to be run "on"  all the time negating some of the energy savings of the fridge.

 

[MtB]

1 hour ago, ditchcrawler said:

They all use the same compressor so its mainly down to insulation, the more insulation the better the fridge the less room for food so they are all basically the same unless you spend a lot of cash

Here are some D which is the best they found 8 Energy Efficient Fridges to Keep It Chill in 2022 - beeco

 

 

 

Thanks but too late. I've just bought four "F" rated fridges!

[ditchcrawler]

15 minutes ago, MtB said:

 

 

Thanks but too late. I've just bought four "F" rated fridges!

With the tiny difference I am not sure I will put my self out

[Tracy D'arth]

5 hours ago, IanD said:

Multiply the kWh/year AC figure by 0.23 (for 12V) to get Ah/day, then divide by 2 to get average power in W.

 

For example, the Liebherr fridge I plan to use (one of the most efficient, but not cheap...) is 115kWh/year which would be 26Ah/day, which is only 13W average power consumption.

 

This assumes a battery voltage a bit above 12V and allows for some power loss in the inverter.

And never opening the door or potting anything not cold in it!  🥶

[IanD]

15 minutes ago, Tracy D'arth said:

And never opening the door or potting anything not cold in it!  🥶

Nope, the standard test procedure includes a realistic number of door openings and closings and the fridge being loaded with "stuff".

[George and Dragon]

1 minute ago, IanD said:

Nope, the standard test procedure includes a realistic number of door openings and closings and the fridge being loaded with "stuff".

Is that in the same way that a standard shopping basket for calculating inflation includes things some people would never buy?

One person's realistic may be another's incredibly unlikely.

[IanD]

1 hour ago, Loddon said:

There lies a problem of modern fridges with complicated electronics. Not all of them will manage to bring the inverter out of standby mode when needed so the inverter has to be run "on"  all the time negating some of the energy savings of the fridge.

 

The same might apply to a lot of modern appliances, including anything with a clock/timer, it's not just a fridge problem.

 

However I'm not convinced that modern fridges behave like this, it all depends how quickly they wake up if you're using an inverter with "skip" mode, and how long and how often the power bursts in this mode are. Do you have any evidence of this problem, and how many (if any) fridges are affected, or are you just speculating that it *might* happen?

 

10 minutes ago, George and Dragon said:

Is that in the same way that a standard shopping basket for calculating inflation includes things some people would never buy?

One person's realistic may be another's incredibly unlikely.

Perhaps, but nevertheless the test does include both opening the door and putting stuff in. If you open the door more often and put more warm stuff in it'll obviously use more power, but the point of the tests -- like any other tests such as car MPG -- is not to cover all possible use cases but to allow an apples-to-apples comparison of different models under standardised conditions.

 

Most people with half a brain don't expect their car to deliver the official WLTP fuel consumption in real life because it depends on driving style and conditions, but the point is that if you choose one with better official MPG than another one then it should also be better in real life. Same for fridges with energy use... 😉

Edited September 8, 2022 by IanD

[blackrose]

I think I'm going to get one of these, mainly because it fits into the space I've got and it doesn't have the space and energy wasting freezer compartment that I don't want. 

 

https://www.cramptonandmoore.co.uk/hoover-hhtl482wk-48cm-88l-a-undercounter-larder-fridge.html

 

Energy efficiency seems as good as anything else unless anyone can see something wrong with it?

[David Mack]

10 hours ago, blackrose said:

According to my battery monitor my small 3 way fridge is drawing 11.3 amps on 12v when run on mains through the inverter.

That doesn't sound too good. According to the instructions posted by A de E, when run directly on 12V it should consume 8A. So either your inverter is consuming a lot of power, or your fridge is much less efficient than it was designed to be.

[GUMPY]

16 minutes ago, IanD said:

However I'm not convinced that modern fridges behave like this, it all depends how quickly they wake up if you're using an inverter with "skip" mode, and how long and how often the power bursts in this mode are. Do you have any evidence of this problem, and how many (if any) fridges are affected, or are you just speculating that it *might* happen?

No speculation.  When I first replaced the 12v  fridge the 230v one had a problem waking up the Victron inverter from one power saving mode, worked with AES mode but not in search mode. Swapped it for the LEC from the house  and problem went away. 

I don't have the old fridge anymore as I left it behind  when we moved house.

 

 

[blackrose]

17 minutes ago, David Mack said:

That doesn't sound too good. According to the instructions posted by A de E, when run directly on 12V it should consume 8A. So either your inverter is consuming a lot of power, or your fridge is much less efficient than it was designed to be.

 

I thought it used more than 8A on 12V? Anyway, my inverter is fine it uses about 1A. I replaced the mains element a couple of years ago so it could be that the element I fitted isn't to spec or isn't exactly in the right position? It's quite difficult to position them correctly because they're not meant to be pushed too far down the tube or they'll quickly burn out.

 

This is the electrical specs for my Dometic RM5310

 

 

Edited September 8, 2022 by blackrose

[ditchcrawler]

33 minutes ago, George and Dragon said:

Is that in the same way that a standard shopping basket for calculating inflation includes things some people would never buy?

One person's realistic may be another's incredibly unlikely.

and car MPG

[IanD]

2 minutes ago, Loddon said:

No speculation.  When I first replaced the 12v  fridge the 230v one had a problem waking up the Victron inverter from one power saving mode, worked with AES mode but not in search mode. Swapped it for the LEC from the house  and problem went away. 

I don't have the old fridge anymore as I left it behind  when we moved house.

 

 

Search mode on the Victron inverters puts out very short mains bursts, something like a couple of mains cycles once every few seconds IIRC. If this wasn't enough to wake your fridge up then this would explain what you saw -- doesn't mean this happens with all inverters and all modern fridges though...

1 minute ago, ditchcrawler said:

and car MPG

...as I said... 😉

[ditchcrawler]

16 minutes ago, David Mack said:

That doesn't sound too good. According to the instructions posted by A de E, when run directly on 12V it should consume 8A. So either your inverter is consuming a lot of power, or your fridge is much less efficient than it was designed to be.

But he is not running the fridge on 12 volts. he is running the invertor on 12 volts and the fridge on 240 volts, it "may" have a thermostat on 240 volts I don't know

[blackrose]

Just now, ditchcrawler said:

But he is not running the fridge on 12 volts. he is running the invertor on 12 volts and the fridge on 240 volts, it "may" have a thermostat on 240 volts I don't know

 

Yes it does. I've said that a couple of times now and Alan has also posted something saying it does.

[IanD]

26 minutes ago, blackrose said:

I think I'm going to get one of these, mainly because it fits into the space I've got and it doesn't have the space and energy wasting freezer compartment that I don't want. 

 

https://www.cramptonandmoore.co.uk/hoover-hhtl482wk-48cm-88l-a-undercounter-larder-fridge.html

 

Energy efficiency seems as good as anything else unless anyone can see something wrong with it?

110kWh/year for an 88l fridge isn't especially good, but you might not be able to find anything better in such a small (narrow) fridge where it's harder to get enough insulation in.

 

Fridge energy ratings are in kWh/l, not just absolute power -- on that criteria the Hoover is 1.25kWh/l-yr whichnis more than 40% higher than the Liebherr I quoted earlier -- which is bigger and a lot more expensive... 😞

Edited September 8, 2022 by IanD

[ditchcrawler]

8 minutes ago, Loddon said:

No speculation.  When I first replaced the 12v  fridge the 230v one had a problem waking up the Victron inverter from one power saving mode, worked with AES mode but not in search mode. Swapped it for the LEC from the house  and problem went away. 

I don't have the old fridge anymore as I left it behind  when we moved house.

 

 

ECO mode When in ECO mode, the inverter will switch to standby when the load decreases below a preset value (min load: 15W). Once in standby the inverter will switch on for a short period (adjustable, default: every 2,5 seconds). If the load exceeds a preset level, the inverter will remain on.