grafozz
Well-Known Member
can you run a domestic fridge ,efficiently , on a boat using a 12 v/240v inverter ? . as domestic fridges are only £100 and 12v fridges are £ 400 +. ?
240 v domestic fridge on a boat ?
- Thread starter grafozz
- Start date
sailorman
Well-Known Member
not very efficient would be my guess
rogerthebodger
Well-Known Member
Domestic fridges can be used on a boat but all domestic fridges are air cooled and so need very good airflow to work efficiently.
The insulation tends to be thinner marine fridges and are polystyrene where as marine fridges use more efficient polyurethane.
IMHO the most efficient marine fridges are also water cooled but there are air cooled marine fridges available.
The insulation tends to be thinner marine fridges and are polystyrene where as marine fridges use more efficient polyurethane.
IMHO the most efficient marine fridges are also water cooled but there are air cooled marine fridges available.
nedmin
Well-Known Member
You will need a big inverter to start the compressor,hence a heavy load. Not worth the effort in my opinion.
Andrew_Palmer
Member
you need to considder the power consumprion of the fridge, if you are taking more than about 300w from a 12v supply you will need a powerful inverter and will drain the batteries in no time.
tcm
...
yeah, why not? I've not done it tho gotta be worth a try. Cheap fridge is under 500W, inverter fifty quid.
Phoenix of Hamble
Well-Known Member
500W is 42amps at 12V, allowing for a slightly inefficient invertor, make that 45amps..... assume a 30% duty cycle, thats 324Ah per day..... you'd need one hell of a set of batteries and charging systems to cover that.....
On top of that its an inductive load, so a 500W invertor wouldn't do the job... you'd probably need a 1Kw invertor..... and that would cost as much as a proper 12V marine fridge!
On top of that its an inductive load, so a 500W invertor wouldn't do the job... you'd probably need a 1Kw invertor..... and that would cost as much as a proper 12V marine fridge!
Gumpy
Well-Known Member
I run a 240v fridge/freezer on the barge so it can be done easily.
A lot depends on what fridge you are looking at.
Like for like a 240v fridge will take about 10-20% more power from the system that a 12v one will.
This wasn't always the case but there have been advances in 12v compressors and the electronics with them that have given rise to this.
You will need a decent size inverter, a lot depends on the make but reckon on a 1kw to allow for start up surge. There used to be some 600w ones that would do it but its not guaranteed.
The above goes for stand alone fridges, built in ones are a different kettle of fish as they are ususlly more efficient because of greater insulation.
One thing to bear in mind with any fridge is that unless its water cooled it needs a decent supply of air to make it work I have two computer fans that draw air from the bilges (dry) and blow it over the matrix at the back of the Fridge, these only come on when the compressor is running so do not draw power 24/7
Oh and as for power consumption:
120w 12v =10Ah x24 =240Ah 40% duty cycle = 96Ah
so just to run the fridge you will need at least 200Ah of batteries and recharge every day.
A lot depends on what fridge you are looking at.
Like for like a 240v fridge will take about 10-20% more power from the system that a 12v one will.
This wasn't always the case but there have been advances in 12v compressors and the electronics with them that have given rise to this.
You will need a decent size inverter, a lot depends on the make but reckon on a 1kw to allow for start up surge. There used to be some 600w ones that would do it but its not guaranteed.
The above goes for stand alone fridges, built in ones are a different kettle of fish as they are ususlly more efficient because of greater insulation.
One thing to bear in mind with any fridge is that unless its water cooled it needs a decent supply of air to make it work I have two computer fans that draw air from the bilges (dry) and blow it over the matrix at the back of the Fridge, these only come on when the compressor is running so do not draw power 24/7
Oh and as for power consumption:
120w 12v =10Ah x24 =240Ah 40% duty cycle = 96Ah
so just to run the fridge you will need at least 200Ah of batteries and recharge every day.
Wino
Well-Known Member
Yes no problem, I have been running a 240v fridge for past 3 years - no probs. BUT I also bought a 240v bottle cooler and have had numerous problems, I have been told it is a different type of cooling unit and does not like the inverter, also have had to alter the wiring as I have been told that the isolation transformer has switched the feed ??? I am far from knowladgeable on electrics so will leave it to someone far wiser than I to explain why this is.
fuss
Well-Known Member
Re: 240 v domestic fridge on a boat ?
see this thread here -
http://www.ybw.com/forums/showflat.php?C...rue#Post1938728
It discusses wether modern a/c fridges are more efficient than modern marine fridges. Its not conclusive.
I still think that there is a possibility that a/c frides are more efficient as much money is spent on making these products efficient. Maybe more on research than on marine fridges??? In Europe they all come with energy ratings that are a very important selling point.
My very good quality 10 year old marine fridge is not efficient.
It would be very interesting if one of the magazines did this test.
see this thread here -
http://www.ybw.com/forums/showflat.php?C...rue#Post1938728
It discusses wether modern a/c fridges are more efficient than modern marine fridges. Its not conclusive.
I still think that there is a possibility that a/c frides are more efficient as much money is spent on making these products efficient. Maybe more on research than on marine fridges??? In Europe they all come with energy ratings that are a very important selling point.
My very good quality 10 year old marine fridge is not efficient.
It would be very interesting if one of the magazines did this test.
charles_reed
Well-Known Member
Re: 240 v domestic fridge on a boat ?
Most marine units use an ac compressor with a solid-state rectifier to change the 12v input.
At least Isotherm and Waco do.
Most marine units use an ac compressor with a solid-state rectifier to change the 12v input.
At least Isotherm and Waco do.
rogerthebodger
Well-Known Member
Re: 240 v domestic fridge on a boat ?
[ QUOTE ]
Most marine units use an ac compressor with a solid-state rectifier to change the 12v input.
At least Isotherm and Waco do.
[/ QUOTE ]
All do because all of them use the Danfoss compressor.
[ QUOTE ]
Most marine units use an ac compressor with a solid-state rectifier to change the 12v input.
At least Isotherm and Waco do.
[/ QUOTE ]
All do because all of them use the Danfoss compressor.
Blue Fox
Well-Known Member
Re: 240 v domestic fridge on a boat ?
I have the experience that domestic fridges are not able to handle the heeling (and other) forces of a boat that is sailing. After approx. 20 hours at rest they start working again!
I have the experience that domestic fridges are not able to handle the heeling (and other) forces of a boat that is sailing. After approx. 20 hours at rest they start working again!
William_H
Well-Known Member
Re: 240 v domestic fridge on a boat ?
Well all accept the Engel which uses an Engel compressor which also runs on AC from a built in inverter. (or at least the older ones did)
I have been told that the fridge AC induction motor wiyh capacitive start is very crityical of the AC waveform. Any tendency to square wave causes losses in heat in the motor. So It must be a pure sine wave inverter.
Newer domestic fridges here in Oz seem to all use the sides and back of the cabinet as condenser to dissipate heat. There are no obvious coils at the back like the old ones. It seems very inefficient to me as the outer shell of the fridge gets warm. Apparently it is OK as the energy rating seems competitive. Here in Oz a standard fridge large by UK standards I think ie 12cuft or more tend to be over a year the greatest electricity user.
Anyway if you spend a lot of time at a powered marina then a 240v fridge makes a lot of sense but you can't just l;eavee it running on 12v inverter without serious considerations of power drain. olewill
Well all accept the Engel which uses an Engel compressor which also runs on AC from a built in inverter. (or at least the older ones did)
I have been told that the fridge AC induction motor wiyh capacitive start is very crityical of the AC waveform. Any tendency to square wave causes losses in heat in the motor. So It must be a pure sine wave inverter.
Newer domestic fridges here in Oz seem to all use the sides and back of the cabinet as condenser to dissipate heat. There are no obvious coils at the back like the old ones. It seems very inefficient to me as the outer shell of the fridge gets warm. Apparently it is OK as the energy rating seems competitive. Here in Oz a standard fridge large by UK standards I think ie 12cuft or more tend to be over a year the greatest electricity user.
Anyway if you spend a lot of time at a powered marina then a 240v fridge makes a lot of sense but you can't just l;eavee it running on 12v inverter without serious considerations of power drain. olewill
