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12v or 240 A+ Fridge


Lady Heidi

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Hey hey - My 3 way fridge is pants and it's Freaky Friday this week at Midland chandlers... But a few people have said that the new 240 fridges are just as efficient .... So ... Do I buy a 12v fridge or get a A+ one and use the money I save to put towards a genny ?? I have 3 leisures, 1000 watt inverter and an 85watt solar panel ? Thanks in advance xx

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Keep your 3 way fridge! Run it only on gas, service it annually and it will serve you well even though it is rather small and has an inadequate freezer compartment. If you remove it you cannot, officially, fit a gas fridge in the future and comply with BSS regulation.

 

This subject has been discussed endlessly in previous threads. A small fridge will consume ~50Ah (600W) per day. If you are in the habit of leaving the inverter on 24/7 a 240V fridge is preferable. For either you will need to install new cables; a 12V fridge will need substantial cables to carry the compressor start-up current without excessive voltage drop; inadequate cables are a common problem that causes 12V fridges to fail to start.

 

If I were to replace my gas fridge for a larger capacity electric one I would have a 240V A+ model. I would modify the thermostat to remotely switch a small, cheap (100W+) dedicated inverter located near to the house batteries. As suggested in other threads I would also install 12V fans to provide cooling air from the bilge. Ideally, I would fill the space to the sides and above the fridge with insulation.

 

Alan

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I've got 240V, 125 litres model with freezer compartment and it uses around 40AH/day. I'm not sure if I would be able to find more efficient 12V version. Also I needed integrated one which I couldn't find within 12V models. I will be also looking into installing fans to provide cooling air from the bilge as I've got deep & cold bilge.

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Too many negatives (for me):

 

- less efficient once inverter conversion efficiency, and its standing current, are taken into account

- less reliable due to relying on the inverter

- small chance that when left unattended, the inverter will develop a fault and overheat causing a fire (yes it does happen).

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Hey hey - My 3 way fridge is pants and it's Freaky Friday this week at Midland chandlers... But a few people have said that the new 240 fridges are just as efficient .... So ... Do I buy a 12v fridge or get a A+ one and use the money I save to put towards a genny ?? I have 3 leisures, 1000 watt inverter and an 85watt solar panel ? Thanks in advance xx

 

A Inverter may use around 15-20ah a day, some may be more. The fridges may be more efficient than 12v ones but check how many amps you inverter will use as well.

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Yes this has been discussed at length quite recently it only really makes sense to go 240v if you already run a big inverter or intend to fit one for other stuff. There is an issue regarding how much current a mains fridge needs to start up, and I wonder if a 1000w inverter is powerful enough?

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Yes this has been discussed at length quite recently it only really makes sense to go 240v if you already run a big inverter or intend to fit one for other stuff. There is an issue regarding how much current a mains fridge needs to start up, and I wonder if a 1000w inverter is powerful enough?

 

I can confirm I managed to start two different models of fridges on 1000w inverter, one of them (rated at 50w) was drawing around 30 amps and the other one (90w) just over 40 amps on start up.

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Im not convinved the arguement for 12v fridges adds up at all. My Bosch fridge uses 118KWh per annum which by my calculation equates to around 25.86Ah per day at 12.5V. Can someone show me a 12V fridge that gets anywhere near that even with inverter losses?

 

Yes I do leave my inverter on all the time.

 

Bosch KUR15A50GB Fridge

 

Redeye

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Im not convinved the arguement for 12v fridges adds up at all. My Bosch fridge uses 118KWh per annum which by my calculation equates to around 25.86Ah per day at 12.5V. Can someone show me a 12V fridge that gets anywhere near that even with inverter losses?

 

Yes I do leave my inverter on all the time.

 

Bosch KUR15A50GB Fridge

 

Redeye

 

What figures have you used for inverter losses?

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Too many negatives (for me):

 

- less efficient once inverter conversion efficiency, and its standing current, are taken into account

- less reliable due to relying on the inverter

- small chance that when left unattended, the inverter will develop a fault and overheat causing a fire (yes it does happen)

 

A 240 modern fridge will most likely be more efficient than a 12v fridge and that's taking inverter losses into account. There are 240v fridges available as low as 85 KWH per pa.

 

We have suffered no unreliability using an inverter.

 

Our inverter has run 24/7 for the past 18 months and has run for similar periods previously, it is now 10 years old.

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A 240 modern fridge will most likely be more efficient than a 12v fridge and that's taking inverter losses into account. There are 240v fridges available as low as 85 KWH per pa.

 

We have suffered no unreliability using an inverter.

 

Our inverter has run 24/7 for the past 18 months and has run for similar periods previously, it is now 10 years old.

 

Great! - How much did the inverter cost?

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Im not convinved the arguement for 12v fridges adds up at all. My Bosch fridge uses 118KWh per annum which by my calculation equates to around 25.86Ah per day at 12.5V. Can someone show me a 12V fridge that gets anywhere near that even with inverter losses?

 

Yes I do leave my inverter on all the time.

 

Bosch KUR15A50GB Fridge

 

Redeye

 

The Victron Multiplus does 5watt in search mode, 10-15w in zero power mode and this is a decent inverter with 93% efficiency. So thats from 8ah - 30ah per day. So with a efficent 240v fridge using around 25ah per day the inverter losses knock this up too around 50ah which is around the same as a old 12v fridge.

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Im not convinved the arguement for 12v fridges adds up at all. My Bosch fridge uses 118KWh per annum which by my calculation equates to around 25.86Ah per day at 12.5V. Can someone show me a 12V fridge that gets anywhere near that even with inverter losses?

 

Yes I do leave my inverter on all the time.

 

Bosch KUR15A50GB Fridge

 

Redeye

 

Totally agree, Our Bosch is 117 KWH per annum and we also get a quality designer fridge, not some bog standard model with an inefficient 12v motor shoved in it and costing a fortune to buy and run.

 

Also just posted with regard to inverters.

 

Great! - How much did the inverter cost?

 

About a grand, It runs other things too BTW. Even if it only ran the fridge though, it would have paid for its self by now in energy savings by using energy efficient 240v fridge.

 

Oh and now 10 years old, that's £100 a year and dropping.

Edited by Julynian
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The Victron Multiplus does 5watt in search mode, 10-15w in zero power mode and this is a decent inverter with 93% efficiency. So thats from 8ah - 30ah per day. So with a efficent 240v fridge using around 25ah per day the inverter losses knock this up too around 50ah which is around the same as a old 12v fridge.

 

Looking at this link http://www.indelwebastomarineusa.com/Products/graphics/DS_IWM_CruiseFridges_EN_2010.pdf

 

a decent size 12v fridge uses around 400-520w per day so thats around 33ah-43ah per day.

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Don't limit yourself to A+ if efficiency is your aim. There's A++ and A+++ as well.

 

For a larder fridge without an ice box you're looking at consumption in the order of:

 

A+ 120kWh/yr

A++ 100kWh/yr

A+++ 65kWh/yr

 

That's a big difference between A+ and A+++

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Looking at this link http://www.indelwebastomarineusa.com/Products/graphics/DS_IWM_CruiseFridges_EN_2010.pdf

 

a decent size 12v fridge uses around 400-520w per day so thats around 33ah-43ah per day.

 

The inverter is on anyway (Victron Quattro) efficiency is 94% 24/5000/120. Also the fridge is a high quality built in fridge virtually silent in operation.

 

To me its an absolute no brainer!

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Don't limit yourself to A+ if efficiency is your aim. There's A++ and A+++ as well.

 

For a larder fridge without an ice box you're looking at consumption in the order of:

 

A+ 120kWh/yr

A++ 100kWh/yr

A+++ 65kWh/yr

 

That's a big difference between A+ and A+++

 

120Kwh/yr = 328wh/day / 93% for inverter losses = 352.7wh/day + 240wh/day for inverter = 592.7wh = 49.4ah/day

65Kwh/yr = 178wh/day / 93% for inverter losses = 191.4wh/day + 240wh/day for inverter =431.4wh = 36ah/day

 

Conclusion: 12v fridge uses less power especially if you don't need a large fridge (25ah/day), but the larger the fridge the more losses of the inverter become minor.

 

Note my inverter calcs are for a Victron multiplus in AES mode (10w), but you can add another 10amp to the figures for normal mode (15w).

Edited by Robbo
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A 240 modern fridge will most likely be more efficient than a 12v fridge and that's taking inverter losses into account. There are 240v fridges available as low as 85 KWH per pa.

 

We have suffered no unreliability using an inverter.

 

Our inverter has run 24/7 for the past 18 months and has run for similar periods previously, it is now 10 years old.

We have just clocked up 12 years with this set up. 1500 w true sine wave inverter and LEC fridge.

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The inverter is on anyway (Victron Quattro) efficiency is 94% 24/5000/120. Also the fridge is a high quality built in fridge virtually silent in operation.

 

To me its an absolute no brainer!

 

Quattro uses around 25w in zero load power is thats an extra 50ah/day for the inverter.

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120Kwh/yr = 328wh/day / 93% for inverter losses = 352.7wh/day + 240wh/day for inverter = 592.7wh = 49.4ah/day

65Kwh/yr = 178wh/day / 93% for inverter losses = 191.4wh/day + 240wh/day for inverter = 543.7wh = 45.3ah/day#

 

Conclusion: 12v fridge uses less power especially if you don't need a large fridge (25ah/day), but the larger the fridge the more losses of the inverter become minor.

As I have said before I have never seen official consumption figures for a 12/24 volt fridge so that it can be directly compared with a 240 volt model

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As I have said before I have never seen official consumption figures for a 12/24 volt fridge so that it can be directly compared with a 240 volt model

 

Agreed the 12v manufactures don't need to prove their consumption figures, I note many only quote average consumption as well, which in reality is meaningless. The ratings figures such as A+ have to be proven.

 

I think the inverter loss argument is now irrelevant. All you need to do is fit enough solar to cope with actual 240v fridge use/consumption and inverter losses. Even if you buy a fridge + 200w of solar and a small inverter to run it, that's still going to be cheaper than many 12v fridges.

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