12v or 240v Fridge ?

[Alan de Enfield]

Hers is an interesting article written in response to a question on an Australian "CamperVan" website.

 

 

I have completed my comparison testing of two 140 Litre fridges, one a 240 volt domestic type running through an inverter, and the other a 12 volt unit.

Well the question has been asked many times, can I buy a cheaper household (domestic) fridge for my motorhome/caravan etc and run it through an inverter?

And the answer is yes you can, but you have to ask the question, will it really save you money?

Now to understand the reason that someone would want to do this is simple, a 12/240 volt fridge made for motorhomes, caravans etc, costs a great deal more than a same sized 240 volt domestic one.

The two fridges that I tested were both 140 litres, though I suspect that the domestic 240 volt one was really 131 litres, it is an ‘LG’ brand model GR-131SSF, cost $299.00, The 12 volt one is a Waeco APR –140RF, cost $1,595.00.

This comparison was purely to find out how much power each of these fridges would consume from a 12 volt battery over a 24 hour period.

Running at the same load and in the same room at the same temperature both inside the fridges and out, these tests were performed under controlled and ideal conditions, the battery voltage was a constant 13.65 volt whilst under load.

I won’t go into all the detail of the monitoring/charging/inverter/battery system at this stage, but it was state of the art and linked to a computer.

My target temperature for inside the fridges was 5 degrees Celsius (second bottom shelf), this was adjusted and set during the 24 hours run up time prior to the test period for each fridge.

The room temperature ranged from 26-29 deg throughout the test (air-conditioned).

The results:

Current consumed during the 24 hour test period.

‘LG’ 240 volt fridge………….99.6Ah TOTAL, with a 7Amp average whilst in the 'on' cycle and 42.2Amp peak on start up.

‘WAECO’ 12 volt fridge……..42.2Ah TOTAL, with a 4.5Amp average whilst in the 'on' cycle.

Now here is my angle on this.

Without going into all the pros and cons of a domestic fridge verses the purpose built fridges for motorhomes etc, like that the insulation in the domestic fridges is not as good, but hey that’s easily fixed with a tube of liquid-nails and some sheets of polystyrene foam right ;-)

Lets look at the practical side of it.

If you are going to be parked up with 240 volt power connected every night (caravan park etc), then the 240 volt fridge is an option worth considering.

If however you like to bush camp a lot, and for extended times, consider this, the extra 57.4 Ah required each to run the 240v fridge over and above the 12v one means at least one extra 120Ah deep-cycle battery will be required...... $$$... and extra weight!

Oh and them Amps have to be replaced everyday too, so if solar is your main battery charging source, then you will need at least an extra 200 Watts of solar panel area, and ....$$$, either way you will have to get the extra power from somewhere.

Hows the cheap fridge looking now?

Edited May 2, 2014 by Alan de Enfield

[cereal tiller]

Hers is an interesting article written in response to a question on an Australian "CamperVan" website.

 

 

I have completed my comparison testing of two 140 Litre fridges, one a 240 volt domestic type running through an inverter, and the other a 12 volt unit.

Well the question has been asked many times, can I buy a cheaper household (domestic) fridge for my motorhome/caravan etc and run it through an inverter?

And the answer is yes you can, but you have to ask the question, will it really save you money?

Now to understand the reason that someone would want to do this is simple, a 12/240 volt fridge made for motorhomes, caravans etc, costs a great deal more than a same sized 240 volt domestic one.

The two fridges that I tested were both 140 litres, though I suspect that the domestic 240 volt one was really 131 litres, it is an ‘LG’ brand model GR-131SSF, cost $299.00, The 12 volt one is a Waeco APR –140RF, cost $1,595.00.

This comparison was purely to find out how much power each of these fridges would consume from a 12 volt battery over a 24 hour period.

Running at the same load and in the same room at the same temperature both inside the fridges and out, these tests were performed under controlled and ideal conditions, the battery voltage was a constant 13.65 volt whilst under load.

I won’t go into all the detail of the monitoring/charging/inverter/battery system at this stage, but it was state of the art and linked to a computer.

My target temperature for inside the fridges was 5 degrees Celsius (second bottom shelf), this was adjusted and set during the 24 hours run up time prior to the test period for each fridge.

The room temperature ranged from 26-29 deg throughout the test (air-conditioned).

The results:

Current consumed during the 24 hour test period.

‘LG’ 240 volt fridge………….99.6Ah TOTAL, with a 7Amp average whilst in the 'on' cycle and 42.2Amp peak on start up.

‘WAECO’ 12 volt fridge……..42.2Ah TOTAL, with a 4.5Amp average whilst in the 'on' cycle.

Now here is my angle on this.

Without going into all the pros and cons of a domestic fridge verses the purpose built fridges for motorhomes etc, like that the insulation in the domestic fridges is not as good, but hey that’s easily fixed with a tube of liquid-nails and some sheets of polystyrene foam right ;-)

Lets look at the practical side of it.

If you are going to be parked up with 240 volt power connected every night (caravan park etc), then the 240 volt fridge is an option worth considering.

If however you like to bush camp a lot, and for extended times, consider this, the extra 57.4 Ah required each to run the 240v fridge over and above the 12v one means at least one extra 120Ah deep-cycle battery will be required...... $$$... and extra weight!

Oh and them Amps have to be replaced everyday too, so if solar is your main battery charging source, then you will need at least an extra 200 Watts of solar panel area, and ....$$$, either way you will have to get the extra power from somewhere.

Hows the cheap fridge looking now?

Thanks

 

This article proves the virtues of the dedicated twelve volt fridge

 

And,makes the 3 way Gas 12/240 Fridge the best choice of all?

 

CT

[Ex- Member]

Clearly that LG 240v fridge isn't very economical, what's it's energy rating?.

 

Our A+ bosch averages under 30ah per day. Unsure of exact inverter losses though.

 

Fridge is 117KWH per year.

[Alan de Enfield]

I believe its a 3* rated fridge.

 

I wonder if anyone has, or knows of anyone, who may have done similar test on readily available Uk fridges

[Ex- Member]

I believe its a 3* rated fridge.

 

I wonder if anyone has, or knows of anyone, who may have done similar test on readily available Uk fridges

 

Any 240v fridge sold today would use nowhere near the amount of amps suggested. I reckon he's possibly used an older fridge or even older inverter. I don't know how 3* equates to our rating system either. Either way those figures are way out in comparison to 2 similar modern 12 & 240v units. I even recall Gibbo agreeing there wasn't much in it when matching our 117KWH unit to a 12v unit even including inverter losses.

Edited May 2, 2014 by Julynian

[PhilR]

Thanks

 

This article proves the virtues of the dedicated twelve volt fridge

 

And,makes the 3 way Gas 12/240 Fridge the best choice of all?

 

CT

 

I really must get my old 3 way Electrolux fridge wired up for 12v operation when the engine is running. AFAIAA the vast majority of those 3 way fridges were just fitted on boats to run on gas (like mine is). The 12v option was normally used by caravanners whilst towing to their destination. But LPG has become much more expensive in recent years and it is looking more economical to use the 12v supply when cruising. The only downside I can see is the agro of lighting the gas at the end of a days boating. Does anyone have any experience of running an old 3 way fridge on 12v?

[cereal tiller]

 

I really must get my old 3 way Electrolux fridge wired up for 12v operation when the engine is running. AFAIAA the vast majority of those 3 way fridges were just fitted on boats to run on gas (like mine is). The 12v option was normally used by caravanners whilst towing to their destination. But LPG has become much more expensive in recent years and it is looking more economical to use the 12v supply when cruising. The only downside I can see is the agro of lighting the gas at the end of a days boating. Does anyone have any experience of running an old 3 way fridge on 12v?

Yep

Fit a Brocott voltage Sensitive relay, approx 13 quid.Fridge is powered up once engine is running

Fit a temp. alarm to to fridge so that it sounds when fridge flue temp. drops below 50-60 degrees centigrade(centre of insulation barrier)

This reminds you that the gas needs lighting when the boat's engine is not charging the batteries.

 

The Gas costs 35-45 pence per d24 hours,so maybe the 12 volt option not viable unless you are cruising 8 hours per day

 

CT

[Robbo]

Clearly that LG 240v fridge isn't very economical, what's it's energy rating?.

 

Our A+ bosch averages under 30ah per day. Unsure of exact inverter losses though.

 

Fridge is 117KWH per year.

My inverter uses around 20ah a day for no load and it's a decent inverter (Victron). The answer is quite simple when choosing a fridge now.

 

12v if you really want to save on power, have no shore power and no need for a inverter.

 

240v if you have a decent inverter, need the inverter on 24/7 for other uses as well or on shore power.

 

It's not now a question of which fridge is more efficient (12v or 240v) but if I want 240v which inverter, as these are nearly as power hungry as fridges.

Edited May 3, 2014 by Robbo

[Phil Ambrose]

My inverter uses around 20ah a day for no load and it's a decent inverter (Victron). The answer is quite simple when choosing a fridge now.

 

12v if you really want to save on power, have no shore power and no need for a inverter.

 

240v if you have a decent inverter, need the inverter on 24/7 for other uses as well or on shore power.

 

It's not now a question of which fridge is more efficient (12v or 240v) but if I want 240v which inverter, as these are nearly as power hungry as fridges.

How very true, have a virtual greenie.

Phil

[Robbo]

Hers is an interesting article written in response to a question on an Australian "CamperVan" website.

 

Just done a Google, the article was written in 2003.

[Ex- Member]

Just done a Google, the article was written in 2003.

 

An he probably used an old 240v fridge back in 2003 going by those figures LOL

[OldGoat]

[pedant ON]

The only real test is have two identical fridges (that means the same carcass) one 12/24V and t'other 240V AC.

You can / could do this because Shoreline use LEC carcases. To complete the test the inverter needs to be just of sufficient rating to run the fridge (in order to keep the idle load down as much as possible).

[pedant OFF]

[Ex- Member]

It's not now a question of which fridge is more efficient (12v or 240v) but if I want 240v which inverter, as these are nearly as power hungry as fridges.

 

 

However 240v A+ rated fridges are quite possibly twice as efficient as 12v fridges

[smileypete]

According to this page the LG uses 291kWh/year!!!

 

http://www.homestore.sg/home-appliance/lg-bar-fridge-gr-131ssf.html

 

So not a very good or up to date test

 

cheers, Pete.

~smpt~

[Phil Ambrose]

 

However 240v A+ rated fridges are quite possibly twice as efficient as 12v fridges

You know what I'm going to say, quite possibly the opposite.

Phil

[peterboat]

I had a 240 fridge freezer and changed to 12v shoreline and I use less power on less than sunny days with the old fridge my voltage was down by days end

 

Peter

[NorthwichTrader]

Is the idea here that the A+ rated fridges are the choice for those considering 240 fridges?

Julynian, can I ask what Bosch fridge you're using presently?

Many thanks, stuart

[Ally]

Our12v fridge uses just 19ah a day. Solar sorts that within less than an hour in summer. Nuff said

[bespin]

Hi looking at a new fridge for our new boat thst came wirh a 240 one installed and it needs replacing and I'm wondering if we should change to 12v we had a shoreline on the last boat. But would need to rewire I think to do this been looking at this A++ fridge freezer http://www.appliancecity.co.uk/liebherr/fridges-and-freezers/tpesf1714/product-16147/

 

The inverter is on all the time anyways for other things so which would be best

[Ex- Member]

Is the idea here that the A+ rated fridges are the choice for those considering 240 fridges?

Julynian, can I ask what Bosch fridge you're using presently?

Many thanks, stuart

 

Hi NT

 

It's this model here. I quickly got this link from Google, I was looking some time ago and you can pick them up new for under £250. We bought ours 7/8 years ago now and never had a problem and we paid just under £200 for it.

 

Do check there isn't a newer model available though, might even be more efficient than 117KWH per year.

 

http://www.rgbdirect.co.uk/ProductDetails.asp?SKUNumber=108929

[Paul C]

Hi looking at a new fridge for our new boat thst came wirh a 240 one installed and it needs replacing and I'm wondering if we should change to 12v we had a shoreline on the last boat. But would need to rewire I think to do this been looking at this A++ fridge freezer http://www.appliancecity.co.uk/liebherr/fridges-and-freezers/tpesf1714/product-16147/

 

The inverter is on all the time anyways for other things so which would be best

 

If the boat already has a decent inverter which will happily run a 230V fridge 24/7 then it makes sense to stick with 230V, due to the lower costs of them.

[Ex- Member]

Hi looking at a new fridge for our new boat thst came wirh a 240 one installed and it needs replacing and I'm wondering if we should change to 12v we had a shoreline on the last boat. But would need to rewire I think to do this been looking at this A++ fridge freezer http://www.appliancecity.co.uk/liebherr/fridges-and-freezers/tpesf1714/product-16147/

 

The inverter is on all the time anyways for other things so which would be best

 

That's not that efficient compared to our Bosche although It does have a freezer box for which that rating is probably good. If you're running an inverter anyway IMO an economic 240v unit would be my preference. You can't rely on energy ratings given for 12v fridges either and they don't compare to ratings for 240v units, also cabling etc and of course the high cost of 12v units in the first place.

[NorthwichTrader]

Many thanks, July, much appreciated! We're going for 240, so really glad to make a start with your choice!

How to find any updates...now that's the new problem!

Many thanks again, happy chugging, Stuart