LEC 240V fridge power consumption with inverter / power audit

[ditchcrawler]

2 hours ago, David Mack said:

So equivalent to 52Ah at 12 V.

Yes, this is a LEC under counter with an ice box and was about 18 years ago, so newer ones may be more efficient, but its still working so not ready for the skip yet

.

[nb Innisfree]

I measured the run time on a 12/24v LEC, repeated it several times, result - approx 12hrs run time per 24hrs, same result winter and summer, never could work out how that happened. 

[Onewheeler]

The fridge with icebox on our boat in France (warmer than UK) consumes an average of 14 W in hot weather. Bog standard A+ spec. The inverter uses a bit less as quiescent consumption: around 9 W from memory.

[ditchcrawler]

1 hour ago, nb Innisfree said:

I measured the run time on a 12/24v LEC, repeated it several times, result - approx 12hrs run time per 24hrs, same result winter and summer, never could work out how that happened. 

My boat is about as warm in the winter as summer apart from a few days. I have the heating on in the winter

[Sea Dog]

On 01/07/2021 at 08:58, David Mack said:

So in the initial run, the inverter + fridge consumed 3.4 Amps and ran for 7.6 hours in 24. So the daily power consumption was 26 Ah.

What about the other 16.4 hours of the inverter running under no load conditions? Not insignificant with some inverters out there.

[ditchcrawler]

6 hours ago, Sea Dog said:

What about the other 16.4 hours of the inverter running under no load conditions? Not insignificant with some inverters out there.

I did put my inverter consumption on there. I also didn't deduct the hours the engine was running. They are just the numbers I recorded,

[Sea Dog]

17 hours ago, ditchcrawler said:

I did put my inverter consumption on there. I also didn't deduct the hours the engine was running. They are just the numbers I recorded,

Yes, it was the bit I quoted which I was querying - the figure there could be a long way out for anyone with a hungry inverter running 24/7 just to service the fridge.

[ditchcrawler]

1 hour ago, Sea Dog said:

Yes, it was the bit I quoted which I was querying - the figure there could be a long way out for anyone with a hungry inverter running 24/7 just to service the fridge.

That is very true, which is why I bought the one I have

[blackrose]

Just picking up this thread from last year...

 

According to my battery monitor my small 3 way fridge is drawing 11.3 amps on 12v when run on mains through the inverter. Usually I run it on gas when away from the mooring for a week or two, but now I'm installing solar and trying to use minimise my use of mains at the mooring, so I want to run the fridge on mains from my inverter. Gas isn't really a viable long term solution at a consumption rate of about 6 weeks/13kg bottle.

 

The mains element on the fridge has a thermostat but I've no idea what proportion of the time it's actually on. I'm thinking of following the example above and insulating the sides of the fridge with some 25mm celotex PIR board as there is a radiator on the back.

 

If the thermostat switches the fridge off say a third of the time, is that 11.3 amps a reasonable consumption figure for a small fridge compared to other A rated mains only fridges? I never run my 3 way fridge directly from 12v because the energy consumption is pretty bad, but how does the mains consumption via inverter compare? I'd rather not get rid of this fridge and replace it with a small mains fridge if I don't have to. The option of running from gas is always good to have. 

[Tony Brooks]

11 minutes ago, blackrose said:

Just picking up this thread from last year...

 

According to my battery monitor my small 3 way fridge is drawing 11.3 amps on 12v when run on mains through the inverter. Usually I run it on gas when away from the mooring for a week or two, but now I'm installing solar and trying to use minimise my use of mains at the mooring, so I want to run the fridge on mains from my inverter. Gas isn't really a viable long term solution at a consumption rate of about 6 weeks/13kg bottle.

 

The mains element on the fridge has a thermostat but I've no idea what proportion of the time it's actually on. I'm thinking of following the example above and insulating the sides of the fridge with some 25mm celotex PIR board as there is a radiator on the back.

 

If the thermostat switches the fridge off say a third of the time, is that 11.3 amps a reasonable consumption figure for a small fridge compared to other A rated mains only fridges? I never run my 3 way fridge directly from 12v because the energy consumption is pretty bad, but how does the mains consumption via inverter compare? I'd rather not get rid of this fridge and replace it with a small mains fridge if I don't have to. The option of running from gas is always good to have. 

 

That consumption is appalling for battery power. A 12V compressor fridge will draw at most half that. An A++ (or whatever the present rating system is) will be very close to the 12V figure of between about 35 and 50 Ah per day allowing for inverter losses that vary from make to make. Why not run it on gas as long as it is a diesel boat.

[Alan de Enfield]

21 minutes ago, blackrose said:

Just picking up this thread from last year...

 

According to my battery monitor my small 3 way fridge is drawing 11.3 amps on 12v when run on mains through the inverter. Usually I run it on gas when away from the mooring for a week or two, but now I'm installing solar and trying to use minimise my use of mains at the mooring, so I want to run the fridge on mains from my inverter. Gas isn't really a viable long term solution at a consumption rate of about 6 weeks/13kg bottle.

 

The mains element on the fridge has a thermostat but I've no idea what proportion of the time it's actually on. I'm thinking of following the example above and insulating the sides of the fridge with some 25mm celotex PIR board as there is a radiator on the back.

 

If the thermostat switches the fridge off say a third of the time, is that 11.3 amps a reasonable consumption figure for a small fridge compared to other A rated mains only fridges? I never run my 3 way fridge directly from 12v because the energy consumption is pretty bad, but how does the mains consumption via inverter compare? I'd rather not get rid of this fridge and replace it with a small mains fridge if I don't have to. The option of running from gas is always good to have. 

 

 

Generally the 3-way fridges are not thermostatically controlled (on the 12v side) and will have a continuous current draw. This is why the manufacturers (Electrolux) actually said in their owners manual to turn the fridge off if parking in the motorway services (obviously a caravan and not a boat)

 

 

 

 

 

 

Edited September 8, 2022 by Alan de Enfield

[MtB]

8 minutes ago, Tony Brooks said:

 

That consumption is appalling for battery power. A 12V compressor fridge will draw at most half that.

 

 

Just for comparison, my Inlander 12v under-counter fridge (4 years old) draws 2.8A while the compressor is running. 

 

Since the thermostat failed on it, I fitted a cheapo 230Vac fridge and inverter. When the 230Vac fridge is running, the inverter draws 4.3A. And 0.5A when the fridge is NOT running. 

 

 

[IanD]

17 minutes ago, MtB said:

 

 

Just for comparison, my Inlander 12v under-counter fridge (4 years old) draws 2.8A while the compressor is running. 

 

Since the thermostat failed on it, I fitted a cheapo 230Vac fridge and inverter. When the 230Vac fridge is running, the inverter draws 4.3A. And 0.5A when the fridge is NOT running. 

 

 

 

But from the battery point of view it's not how much power the fridge takes when the compressor is running that really matters, it's the energy use over a day which includes how often it runs.

 

A modern well-insulated 230V fridge where the compressor takes (for example) 100W but only runs occasionally will flatten the batteries more slowly than an older poorly-insulated 12V one where the compressor takes (for example) 50W but runs much more often. Better insulation is how (usually more expensive) fridges reduce energy consumption, not a low-power compressor.

 

The key number to look at is the annual energy consumption which takes all this into account.

 

Adding the inverter power to the fridge is valid only if you don't have anything else that needs 230V power on board (especially at night) which means the inverter will be running anyway.

Edited September 8, 2022 by IanD

[GUMPY]

Just been looking at my 230v LEC larder fridge

It draws 45 watts when running 

Allowing for inverter losses plus standby at 2w and only running for 1/3 of the time that's about 35ah in a 24hr period or 4amps when compressor is on.

[blackrose]

2 hours ago, Tony Brooks said:

 

That consumption is appalling for battery power. A 12V compressor fridge will draw at most half that. An A++ (or whatever the present rating system is) will be very close to the 12V figure of between about 35 and 50 Ah per day allowing for inverter losses that vary from make to make. Why not run it on gas as long as it is a diesel boat.

 

As I mentioned above, it will use a 13kg gas bottle in about 6 weeks which at current gas prices isn't viable.

 

Looks like I'll need to replace it with a tabletop A++ mains fridge.

2 hours ago, Alan de Enfield said:

 

 

Generally the 3-way fridges are not thermostatically controlled (on the 12v side) and will have a continuous current draw. This is why the manufacturers (Electrolux) actually said in their owners manual to turn the fridge off if parking in the motorway services (obviously a caravan and not a boat)

 

 

 

 

 

 

 

Yes. That's why l don't run it directly from 12v.

[blackrose]

2 hours ago, MtB said:

Since the thermostat failed on it, I fitted a cheapo 230Vac fridge and inverter. When the 230Vac fridge is running, the inverter draws 4.3A. And 0.5A when the fridge is NOT running. 

 

 

Thanks those consumption figures give me something to base the purchase of a new mains fridge on. All the figures I'd seen in product specs tend to give consumption over the year in kWh ac and I was struggling to do a meaningful conversion.

[IanD]

37 minutes ago, blackrose said:

 

Thanks those consumption figures give me something to base the purchase of a new mains fridge on. All the figures I'd seen in product specs tend to give consumption over the year in kWh ac and I was struggling to do a meaningful conversion.

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.

Edited September 8, 2022 by IanD

[GUMPY]

24 minutes 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.

Interesting🤔

My LEC L5017W larder fridge spec says it's  114kWh/year* so should be pretty close to your figures  and yet my measured figures** are higher than that calculation.

 

Oh and it was cheap at £179🤭

 

* See PDF

**See previous post.

444410473 LEC L5017 WHI - SPEC SHEET.pdf

 

 

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.

Edited September 8, 2022 by Loddon

[IanD]

6 minutes ago, Loddon said:

Interesting🤔

My LEC L5017W larder fridge spec says it's  114kWh/year* so should be pretty close to your figures  and yet my measured figures** are higher than that calculation.

 

Oh and it was cheap at £179🤭

 

* See PDF

**See previous post.

444410473 LEC L5017 WHI - SPEC SHEET.pdf 35.2 kB · 0 downloads

 

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...

[Alan de Enfield]

1 hour ago, blackrose said:

 

Thanks those consumption figures give me something to base the purchase of a new mains fridge on. All the figures I'd seen in product specs tend to give consumption over the year in kWh ac and I was struggling to do a meaningful conversion.

 

My Waeco 12v fridge (I know you are looking at a mains fridge) uses ~30Ah per day (measured) including loads of door openings for milk to make tea etc etc.

It runs roughly 33.3% of the time during the day and very little at night when there are no door openings.

Average power consumption quoted by the manufacturer is 45 watts. (call it 4 amps, running (say) 7 hours per day aligns pretty much with my measured ~30Ah per day

[blackrose]

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.

 

Edited September 8, 2022 by blackrose

[ditchcrawler]

5 hours ago, blackrose said:

Just picking up this thread from last year...

 

According to my battery monitor my small 3 way fridge is drawing 11.3 amps on 12v when run on mains through the inverter. Usually I run it on gas when away from the mooring for a week or two, but now I'm installing solar and trying to use minimise my use of mains at the mooring, so I want to run the fridge on mains from my inverter. Gas isn't really a viable long term solution at a consumption rate of about 6 weeks/13kg bottle.

 

The mains element on the fridge has a thermostat but I've no idea what proportion of the time it's actually on. I'm thinking of following the example above and insulating the sides of the fridge with some 25mm celotex PIR board as there is a radiator on the back.

 

If the thermostat switches the fridge off say a third of the time, is that 11.3 amps a reasonable consumption figure for a small fridge compared to other A rated mains only fridges? I never run my 3 way fridge directly from 12v because the energy consumption is pretty bad, but how does the mains consumption via inverter compare? I'd rather not get rid of this fridge and replace it with a small mains fridge if I don't have to. The option of running from gas is always good to have. 

Mine is not a 3 way fridge its a standard domestic 240 volt compressor fridge

[blackrose]

10 minutes ago, ditchcrawler said:

Mine is not a 3 way fridge its a standard domestic 240 volt compressor fridge

 

Ok, but I wasn't suggesting yours was a 3 way fridge?

[ditchcrawler]

4 minutes ago, blackrose said:

 

Ok, but I wasn't suggesting yours was a 3 way fridge?

As it was an old thread some people may not have gone back to the beginning. I am reaching the stage of having to buy a new one as this one is now 20 years old

[GUMPY]

3 minutes ago, ditchcrawler said:

As it was an old thread some people may not have gone back to the beginning. I am reaching the stage of having to buy a new one as this one is now 20 years old

If you want a reasonable one with no ice box you could do worse than an LEC the same as mine.

If you really want to go all out economy of electric buy an under counter freezer and put an external stat on it. Way more efficient than any fridge😉