Using fridge off grid

[Steve_an_Nik]

Curious to know how funsters use their fridges when not on ehu and when off on "off grid"...

Do you run it on gas, generator or is there some other form..

As am I right that it only works on 12v when driving, 240v when on ehu and any other time is gas..

Silly question l know but am rather new to all this motorhome malarkey....

 

[Jo662]

Curious to know how funsters use their fridges when not on ehu and when off on "off grid"...

Do you run it on gas, generator or is there some other form..

As am I right that it only works on 12v when driving, 240v when on ehu and any other time is gas..

Silly question l know but am rather new to all this motorhome malarkey....

Yes you are right on how the fridge works

 

[Steve_an_Nik]

Ahh that good then learnt something along the way... so it is a case of running it on gas when off grid.... many thanks

 

[Tombola]

They use very little gas surprisingly enough so is best to use gas unless you have lots of lithium maybe and lots of solar or charge to put the leccy it back in them..

 

[autorouter]

The Automatic Energy Selection (AES) sequence is a good starting point. It always runs on 240V hookup if available, if not it turns on the gas. When the engine starts and the alternator is on it switches over to the 12V.

A 3-way fridge is very power-hungry on 12V, much worse than the compressor type. If it was powered from only a single leisure battery, you're lucky if it lasts12 hours, so manufacturers usually arrange that it can only go to 12V if the engine is running.

If it's the AES type (ie not manual selection), then if it's running on 12V and the engine stops there is a short delay, 15 minutes or so, before the gas switches on. This is to avoid the gas firing up when you stop for fuel.

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[peterc10]

We have a Dometic AES (automatic energy supply) fridge and freezer. When stopped and no EHU it automatically switches to gas. We have self-refillable bottles so just fill up when needed.

In addition our Votronic MPPT solar regulator notifies the fridge when the leisure batteries are full and the fridge switches to 12v in order to use the free electricity from our solar panels. The regulator checks every half hour and the fridge switches on or off depending upon the state of the batteries. Saves gas in the summer.

 

[Hettie's Crew]

They use very little gas surprisingly enough so is best to use gas unless you have lots of lithium maybe and lots of solar or charge to put the leccy it back in them..

Not my experience at the moment, for some reason the flame is burning almost continuously, it goes off for about 15 minutes then back on for 30-45 minutes. I’ve turned it down to 2 from it’s normal 3 or 4, everything inside is nice and cold but I’m burning through my gas supply.
The only thing I can think of is that we’re not completely level, only tipped forward very slightly though.
It’s so annoying that I think I’ll be using EHU sites until we get home next week, that in itself is annoying.

 

[autorouter]

The only thing I can think of is that we’re not completely level, only tipped forward very slightly though.

Another possibility is the thermostat that tells the control board what the fridge temperature is. It is usually located on the metal heat transfer plate at the top rear of the fridge. It should be firmly attached to the finned plate, so there is good thermal contact. A few on here have reported that it can become loose or even detached. That will make the control board think the temperature is higher than it really is, so will keep trying to cool it further.

 

[Emmit]

Having gone through the turmoil recently of having to consider changing our Fridge/freezer (TEC Tower)
I have seen the figures for a large Fridge/freezer 3 way compression type.
(Dodged that bullet thankyou, just got hit by a non fatal slap to the finances.)

From memory, they are quoting somewhere bet. 400-500 grams of gas consumed per 24hrs.
(With refillable costing about £1.00 a Litre that works out at about £1)

Electricity comes in at 4Kw Hrs, which, if I've got my head around this, means that it would cost
about £1.36 if the site were to charge you the Domestic Rate at the moment. Of course, if
a site were to charge you the Business Rate, that could be as high as 80p per Kw.

One thing it did highlight, (for me anyway) was that, at 4Kw a day, your fridge would use ALL
your allowance at an ACSI site where, I believe the daily allowance is 4Kw.

 

[Figaro]

Not my experience at the moment, for some reason the flame is burning almost continuously, it goes off for about 15 minutes then back on for 30-45 minutes. I’ve turned it down to 2 from it’s normal 3 or 4, everything inside is nice and cold but I’m burning through my gas supply.
The only thing I can think of is that we’re not completely level, only tipped forward very slightly though.
It’s so annoying that I think I’ll be using EHU sites until we get home next week, that in itself is annoying.

Surely that's also going to be much more expensive that just buying the gas ?

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[Hettie's Crew]

Surely that's also going to be much more expensive that just buying the gas ?

Yes, but much better sleep not listening to the gas burner all night.

 

[autorouter]

From memory, they are quoting somewhere bet. 400-500 grams of gas consumed per 24hrs.
(With refillable costing about £1.00 a Litre that works out at about 40p-50p)

LPG is about 493g per litre, so that actually works out at about £1.

 

[Emmit]

LPG is about 493g per litre, so that actually works out at about £1.

I'll change my OP on this, thank you.

 

[poppycamper]

Yes, but much better sleep not listening to the gas burner all night.

That could be another pointer...
On all the fridges I have had the burner was whisper quiet to the point the only place you could hear it was if you put your ear right up against outside vent....
Certainly never heard it inside van.!!

 

[Tombola]

That could be another pointer...
On all the fridges I have had the burner was whisper quiet to the point the only place you could hear it was if you put your ear right up against outside vent....
Certainly never heard it inside van.!!

same

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[Lenny HB]

That could be another pointer...
On all the fridges I have had the burner was whisper quiet to the point the only place you could hear it was if you put your ear right up against outside vent....
Certainly never heard it inside van.!!

On the modern ones the gas burners roar easy to hear inside the van.

 

[Hettie's Crew]

That could be another pointer...
On all the fridges I have had the burner was whisper quiet to the point the only place you could hear it was if you put your ear right up against outside vent....
Certainly never heard it inside van.!!

Our friends have an older 2005 Dometic AES in their motorhome and I can’t hear a thing when it’s on gas. I keep asking them if they’re sure it’s working.
On our 2014 RMDT 8505 the burner’s just behind the lower grill and has always made a fierce roar, bright blue flame when on gas.

 

[GMLS]

We have a Dometic AES (automatic energy supply) fridge and freezer. When stopped and no EHU it automatically switches to gas. We have self-refillable bottles so just fill up when needed.

In addition our Votronic MPPT solar regulator notifies the fridge when the leisure batteries are full and the fridge switches to 12v in order to use the free electricity from our solar panels. The regulator checks every half hour and the fridge switches on or off depending upon the state of the batteries. Saves gas in the summer.

Like that idea.Anyone know if the Victrons can do that as well?

 

[Lenny HB]

On our 2014 RMDT 8505 the burner’s just behind the lower grill and has always made a fierce roar, bright blue flame when on gas.

That is normal on the 8505 had them in the last two vans.

 

[poppycamper]

Our friends have an older 2005 Dometic AES in their motorhome and I can’t hear a thing when it’s on gas. I keep asking them if they’re sure it’s working.
On our 2014 RMDT 8505 the burner’s just behind the lower grill and has always made a fierce roar, bright blue flame when on gas.

RMD 8555 2015 ish...
Whisper quiet and good flame.... circa minus 16 to 18 in freezer 4 or 5 in fridge..... setting 3....

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[paddymcc]

Like that idea.Anyone know if the Victrons can do that as well?

No, I don't believe so, it's only on the larger votronic units that have the S+ option. I have it on my votronic MPPT 350. It seems to be on for 15 minute burst when there's enough solar. The other day it was on fo about 15 minutes per hour.

 

[peterc10]

Like that idea.Anyone know if the Victrons can do that as well?

Not as far as I know. It is why I bought the Votronic. But got a Victron for the new panels I fitted recently for other reasons. The Votronic only works when it thinks the batteries are full and it doesn't matter what charger filled them.

 

[Lenny HB]

I have a Votronic it does ½ blocks.

When I get the new van I will be kitting it out with Victron & Lithium, the plan is to use the relay output on BMV712 to switch the S+ on when the batteries are at 90% and off at 50%. Then to fit a timer inline switching it off and on every hour from say 7 am to 7pm (depending on time of year).
I think it should work planning to have 460 ah of Lithium so probably the timer is OTT.

 

[Jimbohorlicks]

You can fit fans to the top vent of your fridge to help the air circulation and cooling of the refrigerant. Helps to make the fridge more efficient and use less gas.

 

[Lenny HB]

You can fit fans to the top vent of your fridge to help the air circulation and cooling of the refrigerant. Helps to make the fridge more efficient and use less gas.

But if you fit an internal fan as well it works even better but uses more gas, small price for cold beer.

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[Hettie's Crew]

I think I’m going to be chimney sweeping when I get home. The thermostat is fixed in place as it should be, I’ve checked the burner and there are a few deposits laying around in there that maybe from the chimney. It’s never been done to my knowledge.

 

[Bessy765]

On our Dometic fridge freezer, when I heard the gas roaring which was unusual it turned out the secure motion regulator had failed and was letting too much gas through? It also blew the seal on the hob, best to check. Currently in France 700 watts of solar 200 amps lithium Victron 12/2000/80 inverter charger. Full sun batteries 100% running three way fridge on 240 through the inverter. Even allowing for inverter inefficiencies it uses less from the batteries as it’s temp controlled where as 12 volt element runs continuousl.

 

[Lenny HB]

Even allowing for inverter inefficiencies it uses less from the batteries as it’s temp controlled where as 12 volt element runs continuousl.

Unless it's a very old fridge the 12v will be temperature controlled.

 

[Bessy765]

Hi Lenny, we have tried this method on several overnight crossing both 12 and 240 via inverter, its a 2019 Burstner with Dometic ses fridge freezer. We have an app that monitors energy use and the 240 via inverter shows less battery drop. Whether it is because it is a more efficient element although it still requires the inverter I don’t know can only go on the data given. It is currently showing and inverter load of 178 watts at 240 volts, when running 15 watts standby

 

[hja]

Original post is only true with a three way fridge. Compressor fridges run of the leisure battery entirely.