Running a Fridge on Gas on the Move?

[Derek Uzzell]

There’s also the matter of autogas ‘quality’ to consider.

 

When an underslung LPG tank is fitted as standard by a motorhome converter, a gas-locker will probably not be provided. Omission of the gas-locker gains interior storage space and (with most designs) avoids having to cut a big hole in the vehicle’s bodywork. However - unlike a gas system based on user-refillable bottles - an LPG tank/no gas-locker approach commits the motorcaravanner to employ ‘autogas’ (LPG).

 

Manufacturers of ‘sensitive’ gas-fuelled appliances (eg. fridges and heaters) fitted to motorhomes are not overjoyed by the idea of running them on LPG.

 

The Thetford User Manual for my Rapido’s fridge/freezer warns that “A filter must be used when operating on Liqufied Petroleum Gas (LPG). The filter must be prescribed by a qualified technical person”.

 

Rapido’s User Manual goes further, giving reasons for potential malfunctions when LPG is used - unpredictable composition of the LPG product, increased presence of residual evaporation gases compared with ’straight’ propane or butane, and poorly maintained or missing filters in the distribution system failing to remove suspended oil or paraffin residues that can produce phthalates that will irreparably damage regulators. The Manual goes on to say

 

“Warning: In view of all these aspects (quality of the LPG, quality of the distribution system and quality of the filtration system) we strongly advise against using LPG as a substitute gas for supplying the gas appliances in Rapido motorhomes, The repairs are not covered under the warranty.”

 

With a user-refillable bottle system it’s generally straightforward to add a filter (example here)

 

https://www.truma.com/int/en/products/truma-caravan-rv-gas-fittings/truma-gas-filter.html#radius=de

 

between the bottle and regulator, but it’s likely to be more challenging for a tank-based system. I’m guessing that the converters that fit tanks as standard do not fit filters as standard, and that their user manuals do not mention the possible need.

 

[aandncaravan]

Another recent post of a Fridge 12v electrics burning out here :

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Dometic-Fridge-trying-to-kill-me-/48411/

 

However this one is slightly different in that the Fridge inbuilt control panel was the victim of the burning, exactly as per another recent thread on a burnt out 12v Fridge Control panel. Not the Power distribution/charger unit.

The title of the Post : 'Dometic Fridge trying kill me', says it all.

 

 

Both threads seem to indicate an issue with some Fridges safely running on 12v from the Alternator.

 

Note how in the thread the Fridge draw is quoted at 18amps, not unlike the 17amps we have reported and far higher than the 10amps current draw usually expected.

 

 

Combined with the burn outs of Fuseboards and Power Controller/chargers we highlighted above, it would again suggest that running a Fridge on 12v might be a greater fire risk than the Gas option, which this thread eventually established is legal in most Countries with Motorhome Fridges designed for such eventualities.

 

 

 

 

 

 

 

 

 

 

 

 

[dicksob]

Keith, on our IH, which has a similar under chassis tank fitted, we have an on/off switch fitted just to the right of the step at th3 door and slightly under the van, very easy to switch on or off and no crawling under. Has passed inspection on P.O. and DFDS ferries!

Previously in our last van, th3 switch was inside in a rear locker, told due to changed regulations this was no longer allowed?

Bill

[veletron]

Hi

 

The title of my post was possibly a bit melodramatic, but hey - anything burning in a motorhome ain't good, let alone stuff burning near a gas supply.

 

Alan, the element in my fridge is rated at 170W @ 12V eg, 14.1A but we all know that alternator voltages can rise way above this, up to 14.4V for a standard alternator or even 15V for a newfangled smart alternator under breaking. This causes more current to flow - 17A in the case of 14.4V.

 

Now, if the electronics in motorhome control panels whether in the fridge, split/charge or control board were actually designed properly, this would not be an issue, it only becomes an issue due to poor designs on the part of the manufacturers. Something expected to cope with long periods of running @ 17A should actually be rated for 25-30A that way it is not running at the extreme limit of its capabilities and wont get hot and wont catch fire.

 

The solution is for the manufacturers to quit fobbing us off with rubbish kit and actually create kit that isn't nigh-on guaranteed to fail.

 

Personally, I would not drive with the fridge on Gas, too easy to forget to turn it off in a service station, and not that efficient due to the constant re-lighting that would be required. On my old van, I occasionally forgot to switch it back over to 12V (before I fixed the AES). When riding as a passenger in the back, seeking out and fixing rattles, I could hear the igniter trying to re-light the fridge after getting blown out. Ditto on windy nights up at Cairngorm car park. I do think there is a big difference between a naked flame just behind a fridge grille and a naked flame buried deep under the boiler in a Truma, connected to the outside world via (in my van) 3ft of exhaust ducting.

 

More info on my dead fridge here: https://www.veletron.com/dometic-9-series-fridge-burning-12v/

 

Nigel

[Derek Uzzell]

The User Manual for my Thetford fridge/freezer warns

 

“In Europe it is only allowed to run your refrigerator on gas while driving if a gas system with break protection is installed and local regulations are respected”

 

It’s my understanding that the use of ‘break protection’ systems (eg. Truma CS regulators and anti-rupture gas hoses) only allows gas-fuelled HEATING appliances to be legally operated in a moving vehicle (and only then if the ‘break protection’ system had been installed in the vehicle originally).

 

Consequently, if a country has a national law forbidding gas-fuelled appliances being operated in a moving vehicle, although a suitably certified gas-fuelled HEATER may be operated in a moving vehicle in that country if that vehicle has a ‘break protection’ system, it is still not legally permissible to operate a fridge, hob, stove, gas-lights, etc. Merely because a gas appliance is technically capable of operating in a moving vehicle does not mean that one is allowed to operate it.

 

There are 44 countries in Europe, but I don’t know how many have national laws regarding operating gas-fuelled appliances in a moving vehicle. France certainly has such a law, but there may well be others.

 

[aandncaravan]

Veletron, I totally agree that the Fridge 12v installations have not kept pace with the Refrigerators being installed the last 5+ years, especially the big Fridge/Freezers which we have seen draw 17amps.

 

We now advise Hymer/Burstner vehicles to swap the 20amp Fridge fuse by the Starter battery for a 25a component after seeing many melted 20a fuses.

 

But too many Motorhome Electronics manufacturers are using 20 amp rated connectors to run Fridges, only recently have some started to adopt 40a rated connectors.

 

The biggest risk is from those Dealers fitting high power 12v Elements, or complete new Fridges, to older Motorhomes without uprating the 12v circuits.

 

 

 

Derek, there is no law that an impact triggered gas shutoff valve must be fitted to vehicles in the UK, or most of Europe, if a gas appliance is used on the move.

It is 'advised', but not Law.

 

Given the extremely low number of accidents in the UK where 'Gas started' fires followed a collision, I know of only one and no one on the thread had provided any other figures, it doesn't seem sense to me to make it law.

 

In anycase just shutting off the supply at the gas valve still leaves the gas cylinder/tank and pipework to the 'shutoff' valve vulnerable to splits and crushing.

A big impact on a Gas cylinder or tank will almost certainly lead to Gas release, regardless of all other safety measures.

 

While there might be a the very, very smallest risk of running with the Fridge on gas, the real and tangible evidence of a Fridge 12v electrical fire clearly presents a whole lot more real risk. That risk is growing, not diminishing.

 

We got a call last week about a new Dometic Fridge 'smelling of burning' when on 12v operation, so we referred them to Veletron's Thread with advice to contact Dometic.

 

 

 

 

 

 

 

 

[aandncaravan]

For those who think Gas on the move is too much of a risk, but want to avoid 12v problems, another possible option to running the Fridge on 12v on the move is to consider this method 'invented by Weldted' : http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Technical-Alternator-or-Inverter-charging-/48365/

 

It is an unorthodox solution that uses the Fridge 230v operation while the vehicle is moving, but note the Inverter should be connected to the Starter battery only, NOT the Habitation battery.

 

 

This solution also provides better/faster Habitation battery charging from the Alternator without the battery damage that can result from some Battery to Battery chargers.

.

 

 

 

 

[monique.hubrechtsgm]

Running a fridge on the move is normally on 12 volt from the car battery.and car generator. You may have the gascontainers valves open if you have a crash detection shut off device. That in case of a auto energy selector fridge.

[teccer1234]

I was talking to a mate that uses the Portsmouth to Bilbao ferry and he told me that nearly all the MH owners he spoke to left their gas fridge on for the whole trip (2 nights and 1 day,) later I rang Brittany ferries and asked if it was normal to do so, I was told that when booking they are informed to have the gas off but no checks are made at the docks to see if they have done so !!!!, so imagine a car leaking fuel down in the hold !!!!

when I travel on the tunnel I am stopped every time and they check to see that the gas is off at the bottle

[colin]

Herald of Free Enterprise, they will keep doing unsafe things without checks until it all goes wrong.

[Charles]

Allan shows many examples of failed burnt circuit boards and connectors, I'm sure a gas engineer will have many stories of things going wrong on the gas side too. The photographs would probably be of a burnt out vehicle or house rather than just a circuit board.

 

I think I'll use our fridge how it's designed to be used. It will work reliably for many more years. Allan has a skewed view of electrical reliability because every week he sees them burnt out.

[StuartO]

This Thread started a long time ago when Alan (aandncaravan) raised the possibility of using a fridge on gas all the time, including when driving, as the alternative to expensive repairs to the 12v fridge system, which he suggested was pretty inefficient anyway.  It was an interesting idea and certainly one which I've tucked away just in case.  There were lots of contributions from people worried about having a  naked flame burning while using a petrol station and I would probably switch the fridge off in that situation, to avoid any risk of igniting petrol fumes, even if there would need to be a major spill of petrol for that risk to be present.  After all they want you to switch your mobile phone off before entering a petro station, don't they?

So I'm struggling to see any value in resurrecting this thread, many months later,when it has been given a three page airing already.  May I suggest that before anyone else posts here they should at least read the Thread throiugh from the start, to make sure they are contributing something new and worthwhile.

[Billggski]

This thread generated enough hot air to run my fridge for the summer!

 

But the point about gas left on when on ferries is relevant. The Tunnel doesn't like lpg because it's heavier than air and would settle at the lowest point. Having seen what happened to a boat when lpg leaked into the bilge ( the rudder was found two fields away) I am very sensitive to safety issues.

[Alanb]

StuartO - 2017-11-20 3:53 PM

bigparkie - 2017-11-21 6:20 AMExcuse my ignorance but how many litres of gas are in a kg of liquid propane?Regards Richard.

 

Where LPG is propane, 1kg of LPG has a volume of 1.96L. Conversely, 1L of LPG weighs 0.51kg

I have not previously followed this thread in its entirety, so may I make a belated correction to Stuarts statement above.The figure of 1.96L given by Stuart relates to liquid propane and not to propane gas.At 15C and an atmospheric pressure of 1013.25 mbar (metric standard conditions), 1kg of propane will have a volume of 540L. (Source: An ancient Calor leaflet dating from 1976.)However in use the gas is at 30 mbar above atmospheric. At this pressure the volume will be reduced by the ratio 1013.25/(1013.25+30), which gives us about 524.5L.Alan

[colin]

Forgot about this thread, last weekend my fridge started playing up on gas, had to rely on ice packs and driving with 12v.

[stevec176]

This is a bit like reinventing the wheel, it's got so long it keeps repeating its self. Contributors seem to be just rearranging the words to say the same thing. Time to move on.

[Derek Uzzell]

I can ‘freeze’ this thread if it’s generally believed that it has run its course.

[aandncaravan]

Derek, yes please to the Freeze, good idea.

 

(Your wish is my command ;-) )