Switching between 12v and 240v on a fridge/freezer

[Markymark]

Hi All,

 

How does a boat fridge switch between 12v and 240v when plugged in to shoreline, is it just a case of fitting a rocker switch to the 12v and turning off when plugged into shoreline.

 

Cheers

 

Markymark

[Alan de Enfield]

Generally the fridge will have a switch on which you select 12v or 220v (and in some cases another 'switch' that selects 'gas')

 

On our 'old fridge' (before we replaced it) you can see in he top left hand corner of the fridge a 'red' switch, and next to it a 'green' switch, from memory, these were the voltage selector switches.

 

 

 

 

Edited December 13, 2016 by Alan de Enfield

[Markymark]

Generally the fridge will have a switch on which you select 12v or 220v (and in some cases another 'switch' that selects 'gas')

 

On our 'old fridge' (before we replaced it) you can see in he top left hand corner of the fridge a 'red' switch, and next to it a 'green' switch, from memory, these were the voltage selector switches.

 

Versatility-35-25.jpg

 

IMG_20150728_144444.jpg

 

 

Thanks for the speedy response.... cheers Alan

[nicknorman]

Hi All,

 

How does a boat fridge switch between 12v and 240v when plugged in to shoreline, is it just a case of fitting a rocker switch to the 12v and turning off when plugged into shoreline.

 

Cheers

 

Markymark

If this is a fridge that can also run off gas, then be aware that they are incredibly inefficient when running of 12v or 240v. Maybe that doesn't matter too much when running off 240v shore power, but it will do when running off 12v - it will eat batteries!

 

On the other hand if it is electric only with a compressor, it will be ok. However I think this type of fridge is pretty rare.

 

But anyway, there will be a switch on the fridge to select which power source you want to use.

[Tony Brooks]

As you do are not very specific with the type of fridge you have in mind I will give you another scenario.

 

If you have any 12V equipment plus a 240V battery charger with a reasonable output the moment you plug the shoreline into the boat and turn the battery charger on it will be the battery charger supplying all your 12V needs up to its rated out put. If the need is higher than its maximum output the batteries will supply the difference. Hence it looks as if the fridge is running from the mains but it is not. Some fridge manufacturers sell a "box" you put behind teh fridge that does the same thing when the mains are connected.

 

I would emphasise Nick's point about three way fridges running on 12V. There is no thermostats so they draw around 8 amps at 12V 24/7. That is close to totally discharging two "typical" leisure batteries. Not only will this produce solid frozen tomatoes but will also ruin most boat batteries within weeks given typical charging regimes. I understood at least some such fridges have a 240V thermostat but none have 12V ones.

[Alan de Enfield]

................, but it will do when running off 12v - it will eat batteries!

 

 

 

Indeed they do (which is why we changed it for a Waeco)

 

There was no thermostat on the 12v side.

 

The Electrolux managed to consume (continuously) 10 amps (240Ah per day) which is not ideal. They we designed originally for caravans and the instruction manual says to :

 

Plug into the mains overnight before you leave for your holiday, this gets the fridge 'down to temperaure'.

Connect to the cars 12v ONLY whilst the engine is running and ensure to switch off the fridge if stopping the car for more than a couple of minutes.

On arrival at the camp site reconnect to mans electricity or LPG

 

[dmr]

The old gas-12v-240v fridge does not have a pump like a proper fridge, but uses heat to evaporate a fluid behind the fridge which then by some magic takes heat away inside the fridge. Using heat to run a fridge is very very inefficient. It will have separate 12v and 240v heating elements and the 12v heater will use too many amps to be any good on a boat.

The process that the fluid goes through is complicated with three related cycles taking place and was the work of a genius, a certain Mr Einstein.

 

...............Dave

[MtB]

The old gas-12v-240v fridge does not have a pump like a proper fridge, but uses heat to evaporate a fluid behind the fridge which then by some magic takes heat away inside the fridge. Using heat to run a fridge is very very inefficient. It will have separate 12v and 240v heating elements and the 12v heater will use too many amps to be any good on a boat.

The process that the fluid goes through is complicated with three related cycles taking place and was the work of a genius, a certain Mr Einstein.

 

...............Dave

 

 

Really?

 

I thought it was invented by the well known south American physicist Dr Refri G. Erator

[WotEver]

The process that the fluid goes through is complicated with three related cycles taking place and was the work of a genius, a certain Mr Einstein.

 

...............Dave

 

Ahhh... not so. Although Mr Einstein was involved in 'a design' of an absorption fridge, most of the actual development work was carried out by a former student of his, Leo Szilard. However, a year before Einstein's patent Electrolux had already purchased the patents for an absorption fridge which had been designed some 4 years prior to that by two Swedish physicists.

 

https://en.wikipedia.org/wiki/Absorption_refrigerator

 

https://en.wikipedia.org/wiki/Einstein_refrigerator

 

Tony

[dmr]

 

Ahhh... not so. Although Mr Einstein was involved in 'a design' of an absorption fridge, most of the actual development work was carried out by a former student of his, Leo Szilard. However, a year before Einstein's patent Electrolux had already purchased the patents for an absorption fridge which had been designed some 4 years prior to that by two Swedish physicists.

 

https://en.wikipedia.org/wiki/Absorption_refrigerator

 

https://en.wikipedia.org/wiki/Einstein_refrigerator

 

Tony

 

Yes, but the Einstein story is just so much better and does make him a genius, anybody could have invented relativity but the fridge is genius! Is there not a saying, something like one invention might just be luck, but two is the sign of a genius???

 

If Einstein had invented it today his research student would probably not have got a mention.

 

Also, very many inventions where not really down to their credited inventor but were invented some time earlier and failed because they were "before their time". An invention has to be the good idea in the right place at the right time?

 

I believe the transistor was proposed many years before its "invention" but went nowhere because there was no way to make the required quality semiconductor material at the time????

 

...............Dave

[OldGoat]

It's not generally known, but for a short time Danfoss made a 240v to 12v converter which was very small and fitted into the compressor compartment of the fridge.

The OP mentioned fridge / freezer - so unlikely to be the absorption type.

If it's the former the OP is very lucky indeed.

Quote:-

 

 

BD50F

Direct Current Compressor

R134a

12 - 24V DC & 100-240V AC 50/60Hz

General

Code number (without electronic units) 101Z1220

Electronic unit - standard 101N0210, 30 pcs: 101N0211

Electronic unit 12-24V DC - with metal shielding 101N0220, 30 pcs: 101N0221

Electronic unit 12-24V DC - high start performance 101N0230, 30 pcs: 101N0231

Electronic unit 12-24V DC - AEO & metal shielding 101N0320, 30 pcs: 101N0321

Electronic unit 12-24V DC & 100-240V AC 50/60Hz 101N0500, 36 pcs: 101N0501

Approved compressor - electronic unit combinations refer to Instructions for 101N0xxx

Additional approvals e4, C-Tick

Compressors on pallet 150

Application

Application LBP/MBP/HBP

Evaporating temperature °C -30 to 0 (10)

Voltage range (DC& AC) 12-24V DC & 100-240V AC 50/60Hz

Max. condensing temperature continuous (short) °C 60 (70)

Max. winding temperature continuous (short) °C 125 (135)

Cooling requirements

Application LBP MBP HBP

32°C S S F1

38°C S S F1

43°C S S F1

Remarks on application: Fan cooling F1 depending on application and speed.

Motor

Motor type Variable speed

Resistance, all 3 windings (25°C) ! 1.8

Design

Displacement cm3 2.50

Oil quantity (type) cm3 150 (polyolester)

Maximum refrigerant charge g 300

Free gas volume in compressor cm3 870

Weight - Compressor/Electronic unit kg 4.3/0.25

Standard battery protection settings (refer to 101N0xxx Instructions for optional settings)

Voltage 12V 24V

Cut out VDC 10.4 22.8

Cut in VDC 11.7 24.2

Dimensions

Height mm A 137

B 135

B1 128

B2 73

Suction connector location/I.D. mm | angle C 6.2 | 41.5°

material | comment Cu-plated steel | Al cap

Process connector location/I.D. mm | angle D 6.2 | 45°

material | comment Cu-plated steel | Al cap

Discharge connector location/I.D. mm | angle E 5.0 | 21°

material | comment Cu-plated steel | Al cap

Connector tolerance I.D. mm ±0.09, on 5.0 +0.12/+0.20

Remarks:

S = Static cooling normally suffi cient

O = Oil cooling

F1 = Fan cooling 1.5 m/s

(compressor compartment temperature

equal to ambient temperature)

F2 = Fan cooling 3.0 m/s necessary

SG = Suction gas cooling normally suffi cent

[dmr]

It's not generally known, but for a short time Danfoss made a 240v to 12v converter which was very small and fitted into the compressor compartment of the fridge.

The OP mentioned fridge / freezer - so unlikely to be the absorption type.

If it's the former the OP is very lucky indeed.

Quote:-

 

 

BD50F

Direct Current Compressor

R134a

12 - 24V DC & 100-240V AC 50/60Hz

General

Code number (without electronic units) 101Z1220

Electronic unit - standard 101N0210, 30 pcs: 101N0211

Electronic unit 12-24V DC - with metal shielding 101N0220, 30 pcs: 101N0221

Electronic unit 12-24V DC - high start performance 101N0230, 30 pcs: 101N0231

Electronic unit 12-24V DC - AEO & metal shielding 101N0320, 30 pcs: 101N0321

Electronic unit 12-24V DC & 100-240V AC 50/60Hz 101N0500, 36 pcs: 101N0501

Approved compressor - electronic unit combinations refer to Instructions for 101N0xxx

Additional approvals e4, C-Tick

Compressors on pallet 150

Application

Application LBP/MBP/HBP

Evaporating temperature °C -30 to 0 (10)

Voltage range (DC& AC) 12-24V DC & 100-240V AC 50/60Hz

Max. condensing temperature continuous (short) °C 60 (70)

Max. winding temperature continuous (short) °C 125 (135)

Cooling requirements

Application LBP MBP HBP

32°C S S F1

38°C S S F1

43°C S S F1

Remarks on application: Fan cooling F1 depending on application and speed.

Motor

Motor type Variable speed

Resistance, all 3 windings (25°C) ! 1.8

Design

Displacement cm3 2.50

Oil quantity (type) cm3 150 (polyolester)

Maximum refrigerant charge g 300

Free gas volume in compressor cm3 870

Weight - Compressor/Electronic unit kg 4.3/0.25

Standard battery protection settings (refer to 101N0xxx Instructions for optional settings)

Voltage 12V 24V

Cut out VDC 10.4 22.8

Cut in VDC 11.7 24.2

Dimensions

Height mm A 137

B 135

B1 128

B2 73

Suction connector location/I.D. mm | angle C 6.2 | 41.5°

material | comment Cu-plated steel | Al cap

Process connector location/I.D. mm | angle D 6.2 | 45°

material | comment Cu-plated steel | Al cap

Discharge connector location/I.D. mm | angle E 5.0 | 21°

material | comment Cu-plated steel | Al cap

Connector tolerance I.D. mm ±0.09, on 5.0 +0.12/+0.20

Remarks:

S = Static cooling normally suffi cient

O = Oil cooling

F1 = Fan cooling 1.5 m/s

(compressor compartment temperature

equal to ambient temperature)

F2 = Fan cooling 3.0 m/s necessary

SG = Suction gas cooling normally suffi cent

 

You don't see specs like that these days, more like "offers an immersive refrigeration experience and available in cool black finish stainless steel"

 

................Dave

[Alan de Enfield]

 

The OP mentioned fridge / freezer - so unlikely to be the absorption type.

 

 

You are correct that the 'headline' states Fridge / Freezer, but the question in the text relates to a Fridge only.

 

There may well have been at some point - but I am not aware of any 12v / 220v Fridge/Freezer combo's.

[Markymark]

If this is a fridge that can also run off gas, then be aware that they are incredibly inefficient when running of 12v or 240v. Maybe that doesn't matter too much when running off 240v shore power, but it will do when running off 12v - it will eat batteries!

 

On the other hand if it is electric only with a compressor, it will be ok. However I think this type of fridge is pretty rare.

 

But anyway, there will be a switch on the fridge to select which power source you want to use.

Thanks for your response, at the moment I haven't brought a fridge, would a 3way be better running on the gas most of the time? I get what your saying about the 12v draining the batteries, I have a camper van that drains the leisure batteries when not plugged in to elec hook up, I'm new to boating, I have solar but I'm sure that will only be effective in the summer month's, I'm on a constant cruise but not always with the boat..... what do you suggest?

[WotEver]

Thanks for your response, at the moment I haven't brought a fridge, would a 3way be better running on the gas most of the time? I get what your saying about the 12v draining the batteries, I have a camper van that drains the leisure batteries when not plugged in to elec hook up, I'm new to boating, I have solar but I'm sure that will only be effective in the summer month's, I'm on a constant cruise but not always with the boat..... what do you suggest?

Your best bet would either be a 12V compressor fridge (expensive) or a 240V fridge run from a small inverter (probably higher battery usage). Or, if you will be having a large inverter anyway that'll be permanently switched on, then you could power a mains fridge from that.

 

Edit just cos I can

Edited December 13, 2016 by WotEver

[nicknorman]

Thanks for your response, at the moment I haven't brought a fridge, would a 3way be better running on the gas most of the time? I get what your saying about the 12v draining the batteries, I have a camper van that drains the leisure batteries when not plugged in to elec hook up, I'm new to boating, I have solar but I'm sure that will only be effective in the summer month's, I'm on a constant cruise but not always with the boat..... what do you suggest?

 

You have 2 choices in theory, get a gas fridge and run it off gas. Or get a compressor 12v fridge and run it off electricity. A good modern one will use about 30AH per day, double that if it is a fridge freezer. I say "in theory" because if there isn't a gas fridge already there then it will be a major issue to fit one since it needs an external flue and of course gas piping to the fridge. I am not totally sure (someone will be along in a minute to confirm or refute) that gas fridges are no longer allowed as a "new install" under the regulations.

[WotEver]

Deleted 'cos I talked about gas fridges and Nick's already beaten me to it.

Edited December 13, 2016 by WotEver

[Alan de Enfield]

Thanks for your response, at the moment I haven't brought a fridge, would a 3way be better running on the gas most of the time? I get what your saying about the 12v draining the batteries, I have a camper van that drains the leisure batteries when not plugged in to elec hook up, I'm new to boating, I have solar but I'm sure that will only be effective in the summer month's, I'm on a constant cruise but not always with the boat..... what do you suggest?

 

If it is within the budget I would suggest you go for one of the modern (fairly efficient) 12v fridges such as the Waeco, it only uses about 30Ah per day which is easily maintained / replaced by a small solar panel set up (100w would be plenty - but would obviously depend on your other electrical demands).

[MtB]

 

You have 2 choices in theory, get a gas fridge and run it off gas. Or get a compressor 12v fridge and run it off electricity. A good modern one will use about 30AH per day, double that if it is a fridge freezer. I say "in theory" because if there isn't a gas fridge already there then it will be a major issue to fit one since it needs an external flue and of course gas piping to the fridge. I am not totally sure (someone will be along in a minute to confirm or refute) that gas fridges are no longer allowed as a "new install" under the regulations.

 

 

I think it's more a case of gas appliances needing to be installed in accordance with the manufacturers' instructions, and no-one knowing of a gas fridge stated by the manufacturer as being suitable for installation in a boat.

[DHutch]

We have a compressor based 240 vac and 24vdc Engle fridge.

 

As said, it will internally switch to use the available supply, selecting 240 vac in preference if both are present.

 

There is then an isolator on both supplies, a switched fcu on the 240vac side where i leaves the ring main, and at the breaker on the 24 vdc side, so we can further choose.

 

In practice, its a lot louder on 240vac so often even when on mains we run it off the batteries and hence charger.

 

 

Daniel

[cuthound]

I think it's more a case of gas appliances needing to be installed in accordance with the manufacturers' instructions, and no-one knowing of a gas fridge stated by the manufacturer as being suitable for installation in a boat.

Exactly this.

 

Whilst it is pretty certain that canal boats will rarely if ever heel over long enough to move the flame away from the flame failure device, this is not the case for lumpy water boats. Much easier for the fridge manufacturer to say "unsuitable for boats", rather than try to identify which boats are suitable.

 

Edited for clarity.

Edited December 15, 2016 by cuthound

[DHutch]

Indeed.

 

IE, they are not banned, the rules just state they need to tick a box than none bother to tick.

 

 

That said, while not the case in all applications, and an off-grid liveaboard situation being borderline, in general a good electric compressor fridge is a more simple option for most people. Certainly if the boat is mainly used while underway, even a large domestic 240vac run off an inverter is a practical option.

 

 

Daniel

[Richard10002]

Thanks for your response, at the moment I haven't brought a fridge, would a 3way be better running on the gas most of the time? I get what your saying about the 12v draining the batteries, I have a camper van that drains the leisure batteries when not plugged in to elec hook up, I'm new to boating, I have solar but I'm sure that will only be effective in the summer month's, I'm on a constant cruise but not always with the boat..... what do you suggest?

 

If you havent bought a fridge, i am wondering why you are considering a 3 way model? If you buy a 12V fridge, (£450-£500 or so), you can run it from the batteries at all times, and can charge the batteries from shore power when you have the opportunity.

 

If you havent already got a 3 way fridge, or if the boat didnt have one fitted previously, you will have to run the gas supply to the fridge, and arrange a suitable flue arrangement - not easy if my knowledge of instant gas water heaters is anything to go by

[MtB]

 

If you havent already got a 3 way fridge, or if the boat didnt have one fitted previously, you will have to run the gas supply to the fridge, and arrange a suitable flue arrangement - not easy if my knowledge of instant gas water heaters is anything to go by

 

 

Why? Gas fridges are designed to operate without a flue.

 

The flue kit you mention is just a placebo for people who know nothing about gas and insist on having one.

[Dave_P]

Just to throw another option into the mix.

 

You could get an A+++ rated 240v chest freezer (bear with me...) and fit a thermostat to maintain a temp inside of around 4-5 degrees. Then run that through an efficient inverter.

 

The advantage is that a chest freezer is far better insulated than a fridge and will stay cool far better than a normal larder fridge.

 

More info here: http://www.bimblesolar.com/cheap-solar-fridge

 

I've not tried this but the logic makes sense to me.