Compressor Versus Absorption Motorhome Fridge.

[Bevbun]

Looking for advice, have a domestic 3 way fridge which is totally unreliable so looking to swap for possibly a compressor 12/24 v fridge with freezer space . So, any reasons why I shouldn’t change it? If I do what do I need to be looking for? Any help appreciated

 

[TCG]

Think they went a bit over kill unless your original wiring was crap, 10mm so roughly 70amps, what is the fridge rated at?
Which Dometic Workshop fitted this and was it under warrenty or cost to you

Tewkesbury workshop.. cost £2,388 RCD10.5XT
rather have bigger wires than smaller i will get my pop corn out as well

 

[TCG]

1967bowesj correction wiring 6mm fuse 10amp

 

[ianp]

1967bowesj correction wiring 6mm fuse 10amp
View attachment 940891

You wouldn't need much seperation between battery and fridge to exceed a 6mtr cable run there and back.......

 

[Sheddy]

Me too!

I have a Dometic RMSL8500 and likewise can't find a wheel arch compressor fridge.

Neither can I get hold of Thetford to ask! They refer to their dealers who cannot answer!

Any ideas?

Right now I may have to raise the floor to above wheel arch and rehouse the microwave which is above the fridge. Not a perfect solution. Turns a simple job into a project.

Tony

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[Kthryn]

Popcorn indeed lol

They probably fitted a different 12V feed to the compressor fridge because the original 12V feed turned off when the engine was turned off.

The original feed would easily have been good enough, if only it didn't turn off when you turned the engine off

If youre only using 1/3 the amps you don't need thicker wire and if a small invertor can run a 240v fridge there cant be much inrush current.

We still use a 3 way absorption fridge and have weeks away off grid running the fridge from gas. No need to worry about gas not being available we have a pump to refil bottles at home from a bottle that is delivered to home

 

[Jabstatt]

I should have said that the existing is a 130 litre fridge.

 

[Richard n Ann]

Popcorn indeed lol

They probably fitted a different 12V feed to the compressor fridge because the original 12V feed turned off when the engine was turned off.

The original feed would easily have been good enough, if only it didn't turn off when you turned the engine off

If youre only using 1/3 the amps you don't need thicker wire and if a small invertor can run a 240v fridge there cant be much inrush current.

We still use a 3 way absorption fridge and have weeks away off grid running the fridge from gas. No need to worry about gas not being available we have a pump to refil bottles at home from a bottle that is delivered to home

The original 12v element feed does turn off with the engine, you have to find the cable at the fuse box and make it a permanent fused supply.

I've used the element cable for mine, but I'm going to replace it with a thicker cable after this trip as I've noticed a couple of times when I get up for the toilet at about 5am the fault LED is flashing the low voltage code, it does start up after about 4 attempts and the battery isn't at the 10.4v cut off but it must dip down just for a microsecond at start up.

Startup current is similar to a motors LRA (Lock Rotor Amps) and can be 6 times the full load run current, and even more when the voltage is lower

 

[Steve and Denise]

Knowing your electrical knowledge is it not possible to fit a soft start ? Richard n Ann

 

[1967bowesj]

You wouldn't need much seperation between battery and fridge to exceed a 6mtr cable run there and back.......

But is that there and back or one way, try looking up voltage drop fir those lengths

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[Richard n Ann]

Knowing your electrical knowledge is it not possible to fit a soft start ? Richard n Ann

Yes it's possible with DC compressor motors... But the Danfoss (secop? I think they call themselves now) compressor on my fridge has it's own microprocessor module that runs the motor so you can't really change that

 

[ianp]

we have a pump to refil bottles at home from a bottle that is delivered to home

What is the pump and what is the procedure you adopt to refill a gas cylinder please?

 

[Pausim]

But is that there and back or one way, try looking up voltage drop fir those lengths

The voltage drop calculator I like uses the one way circuit length for the calculation i.e. it assume the electricity has to do a return journey.

Voltage Drop Calculator | 12 Volt Planet

Use our Voltage Drop Calculator to select the correct Cable for your campervan, motorhome or boat wiring application. Auto and Marine Electrical Components from 12 Volt Planet - Cable Size Calculator

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[ianp]

But is that there and back or one way, try looking up voltage drop fir those lengths

Why would I try and second guess the engineers that designed and developed the equipment.......as to is it there and back or one way a quick email to the tech department would establish that.......

 

[Richard n Ann]

What is the pump and what is the procedure you adopt to refill a gas cylinder please?

You don't need a pump, just connect the bottles and make the receiving bottle colder and the liquid will flow quite quickly into the cooler bottle.
You can either pour a kettle of hot water on one (most popular) or put the other in a cold water bath.

Never done it with LPG but done it many times with AC and fridge refrigerant which is exactly the same, sometimes you've got to warm a bottle up to get it to go into the system

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[gus-lopez]

Whilst compressor fridges do not need wall vents like a three way fridge, you still want the back of them to be as cool as possible.

This^^^^^^^^

The hotter the back of the compressor fridge is, the more power it uses to keep the inside cool.

^& This ^^^^^^^^^^
I left one freezer running when we left in May in the coolset part of the house. average daily usage was 0,7Kw
This gradually increased to 1,89kw by the time we returned in august.Solely due to rising temperatures

 

[ianp]

You don't need a pump, just connect the bottles and make the receiving bottle colder and the liquid will flow quite quickly into the cooler bottle.
You can either pour a kettle of hot water on one (most popular) or put the other in a cold water bath.

Never done it with LPG but done it many times with AC and fridge refrigerant which is exactly the same, sometimes you've got to warm a bottle up to get it to go into the system

Thanks R&A, I know that method well which is why I was intrigued by the 'pump' method. It may afford better control when trying to pin the recipient bottle down to 80% if its not internally valved......

 

[Kthryn]

Thanks R&A, I know that method well which is why I was intrigued by the 'pump' method. It may afford better control when trying to pin the recipient bottle down to 80% if its not internally valved......

Ahh I see youre not really interested ;-) So I'll just tell you that our gas bottles may afford to be safe fill bottles that do have the 80% fill limiter and the pump works better than any hit and miss or problematic heat difference method.

Also the heat difference method works even worse if youre trying to fill a vehicle tank that has a one way valve on the tank and another on the fill connector because even if one tank has a bit more pressure than the other (enough to make gas shift from one to the other) the one way valves may need still a bit more pressure difference to open them and keep them oppen. Another thing about the pressure difference method is if you shift warm gas into a cooler tank the warm gas is still warm gas in the cooler tank so soon both tanks can be near same temp and pressure - you could be there all day trying to fill one from the other.

Then just for fun its frowned on and considered unsafe to heat gas bottles but you want to pour boiling water on one ;-)

 

[ianp]

Ahh I see youre not really interested ;-) So I'll just tell you that our gas bottles may afford to be safe fill bottles that do have the 80% fill limiter and the pump works better than any hit and miss or problematic heat difference method.

Also the heat difference method works even worse if youre trying to fill a vehicle tank that has a one way valve on the tank and another on the fill connector because even if one tank has a bit more pressure than the other (enough to make gas shift from one to the other) the one way valves may need still a bit more pressure difference to open them and keep them oppen. Another thing about the pressure difference method is if you shift warm gas into a cooler tank the warm gas is still warm gas in the cooler tank so soon both tanks can be near same temp and pressure - you could be there all day trying to fill one from the other

So what is the pump and what procedure to you employ?

 

[Kthryn]

So what is the pump and what procedure to you employ?

Its a pump we bought from Simon who converts cars campervans etc to run on LPG think his firm is called LPGC

Fit a connector to the safety fill bottle or LPG filler on the side of the van whichever we want to fill with LPG, fit a connector to the gas bottle were getting gas out of, then the pump lines click into the connectors, then the pump power cable is connected to the battery under the bonnet. The bottle were pumping gas out of has to be upside down to get all the gas out but we start pumping gas out with it on its side and turn it upside down when it gets to around half full

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[Helgamobil]

Looking to replace an undercounted, over wheel arch, 3 way fridge with a compressor fridge but haven’t found anything to fit!!! Van is an Autosleeper Nuevo 2004.
Anyone found the answer ??

Have you looked at marine or chandlers websites?
In a previous life we had a standard domestic fridge converted to DC, but not worth bothering these days when so many compressor DC fridges are available.

 

[SpeedyDux]

The Waeco top loading compressor fridge in the previous camper was inaudible when running. A wonderful thing.

The current van came with a Vitrifrigo 90L compressor fridge with small freezer compartment. It sits next to my side of the bed and I did find it a bit noisy whenever it cuts in. There is no night setting so I used to switch it off at night. It must be well insulated because the contents never spoiled.

I am now used to the noise from this fridge so I can leave it switched on and still sleep OK.

One tip: I use the roll-out Fiamma awning to keep that side of the van cooler when the sun shines. I think that helps to reduce the load on the fridge.

 

[Jabstatt]

I hope that I am wrong, but a call to Thetford suggests that they don't do a wheel arch model.

I have been unable to find a direct replacement for my RMSL 8500.

I am trying to avoid woodwork and associated scope for inconsistent inside appearance!

Tony

 

[wfdTamar]

My Beko TSE 1284 240 volt fridge (€219 last time I saw one) is incredibly quiet. I get more noise from the Triton vent fan (around £65) if that comes on and the fan in my solar controller (when that comes on). The Victron Phoenix 800VA inverter (around £200) makes a little hum for a second or two and its fan comes on for a few seconds too. I have it under the floor of a cupboard so it's very quiet too.

Total cost around £435 vs a Dometic CRX110 at £1249 (there are cheaper 12 volt compressor fridges, but then there are cheaper mains fridges than the Beko too).

 

[Richard n Ann]

am trying to avoid woodwork and associated scope for inconsistent inside appearance!

Fit a compressor kit then, the perfect solution and easily done

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[Kthryn]

I like compressor fridges they work great and at any angle.
But there's talk about noise, absoption 3 way fridges are silent.
You need to have a lot of battery storage prefrebly lithium and solar panels if you want to stay off grid. Think we'd have concerns about flattening even a big expensive lithium battery even with lots of expensive solar off grid in the UK on dull weeks.
If you have EHU a absoption and compressor fridge will do a similar job running off 240V. Might need a regulator/charger or invertor to run a 12V compressor off 240v or 240v compressor off 12v, more expense?
Can run a absoption of gas, no need to be concerned or worried about batteries, solar, invertors and not have to pay out in front to buy them and no noise. This is when to us absoption fridges shine over compresors to us.
So both types equaly useful when running on either 12v or 240v, compressor might need a charger or invertor to run on 12 or 240 where absoption can do both without charger or invertor. Thats when driving though, when parked up and no charge from engine thats when ability to run on gas can make a big difrence, no need for batteries solar or invertors when running on gas. Well continue to use our absoption for now. Using our pump to fill our van and gas bottles from big 47kg bottles so gas is cheaper and we never run out. It would take many years for a compresor to save any money even if related stuf like batteries solar and invertors didnt go wrong. Can do without having to worry about flat battery meaning loss of fridge when parked up without EHU. You can flatten any size battery if the sun doesnt shine long enough and you go away off grid for long enough, doubt many with compressors would get good results doing northern europe in winter to see the northern lights off grid.

Thought about having a separate 240v freezer to run off an invertor, when it's on if you have a cool box you can have a fridge without having a fridge, freeze bottles of water and use them to keep a coolbox cool.

 

[Bevbun]

I have a coachbuilt van and took the old fridge out and put the Thetford T2160 in going through the passangers front door. Tilt the back of the seats all the way back. slide the fridge/freezer in. Needed two people.

That is my plan should we bite the bullet

 

[Bevbun]

Popcorn indeed lol

They probably fitted a different 12V feed to the compressor fridge because the original 12V feed turned off when the engine was turned off.

The original feed would easily have been good enough, if only it didn't turn off when you turned the engine off

If youre only using 1/3 the amps you don't need thicker wire and if a small invertor can run a 240v fridge there cant be much inrush current.

We still use a 3 way absorption fridge and have weeks away off grid running the fridge from gas. No need to worry about gas not being available we have a pump to refil bottles at home from a bottle that is delivered to home

We off grid a lot too but our prob is with the gas burners not behaving and fed up of no fridge in hot weather!