LPG Gas indicator

Slightly confused, is this normal for a van conversion!

In my Warwick XL I have a 25ltr lpg gas tank underslung, the LED indicator has 9 led's to show full, on our last outing it got down to 2 led's(<1/4 full) so we decided to fill up when we saw an lpg station assuming we had got down to less that 6ltrs, but to my surprise it only took 8ltrs instead of approx 19ltrs. So is this normal or is the calibration way out ? or am I just getting too old(probably).

TIA
Peter

I have a 25l tank on my Nuevo and have now filled it 3 times.

The first time it was down to 2 dots and took just under 12l.
The second time was a top-up at the start of this season, 8l.
And finally after a 6 week tour and a 1 week music festival with only the red led showing I got 13l in.

So my gauge isn't accurate either.

One thing to note though. Your tank has a capacity of 25l but is designed to not be filled over 80% so from empty to full is 20l.

Same here. The first time I found out that the gauge is wldly inaccurate happened to coincide with both a thread on the Forum about this, which included the advice to get the tank re-aligned as that affects the accuracy of the gauge, and with an iminent first hab service at Willersey. So my tank was realigned.

But I was much amused by the comment of my local Calor depot, just before we went away to France for a few weeks. The guage suggested I could take about 8 litres, but when the pump cut out at about £2.40 worth, he said that I wouldn't keep Calor in business for long...

The LPG guage is about as accurate as those of the water tanks!

I think it's a little misleading for AS to boast of a 25 litre tank then hide in the small print of page 7-5 of the manual that the float valve cuts off at 80% to allow space for the gas to expand so the maximum gas it can contain is 20 litres (as has been said already). It's a 20 litre tank in plain language.
Even given this, the gauge seems to read low. If yours took 8l then it should have been showing 60% (12l/20l)
I have noticed ours shows a reading when I turn the ignition on and then rises a few minutes later.
It would be best if it was accurate but I prefer it to read low rather than high.

I haven't done it but I understand you can fill up at fuel stations in Europe so I am not too concerned about running low on gas when touring.

Ours also reads low, 3 lights left takes about a fiver to refill, so its still about half full on 3 lights.. Also , the slope of the ground both front to rear and sideways has a dramatic impact on the reading. I'm sure I read somewhere that the tank rotation that Cymro mentions above has been sorted on later tanks and later vehicles by fitting tanks that cannot rotate and are therefore correct from the start.

Another connected minor issue with the gas that I have experienced, is that autogas is not the same mix all year round. It has a higher Propane content in the winter and a greater Butane content in the summer months. Twice, on an early frosty morning, our Truma panel has showed an error code, which when looked up has said " too much butane in the propane " or similar. To counter this I try to run the tank down through the late summer and early autumn and only refill it when we start to get colder weather.

AutoSleepyDon wrote:I think it's a little misleading for AS to boast of a 25 litre tank then hide in the small print of page 7-5 of the manual that the float valve cuts off at 80% to allow space for the gas to expand so the maximum gas it can contain is 20 litres (as has been said already). It's a 20 litre tank in plain language.
Even given this, the gauge seems to read low. If yours took 8l then it should have been showing 60% (12l/20l)
I have noticed ours shows a reading when I turn the ignition on and then rises a few minutes later.
It would be best if it was accurate but I prefer it to read low rather than high.

I haven't done it but I understand you can fill up at fuel stations in Europe so I am not too concerned about running low on gas when touring.

it is misleading but I came at it from the other direction. I knew I had to have a maximum of 80% lpg to be allowed in the channel tunnel and wondered how I could manage that. Knowing it cuts out at 80% makes getting on a train (and possibly ferry?) a lot easier.

You can get log in Europe but will probably need an adaptor, or several if you are touring. I needed a dish adaptor when I filled in Czech.

AutoSleepyDon wrote:I think it's a little misleading for AS to boast of a 25 litre tank then hide in the small print of page 7-5 of the manual that the float valve cuts off at 80% to allow space for the gas to expand so the maximum gas it can contain is 20 litres (as has been said already). It's a 20 litre tank in plain language.

It's a standard practice that tanks are only filled to 80% - my old VW T25 was exactly the same so nothing has changed in many decades.

Because most people know this, if they stated a 20L tank, people who know this would think they can only fill it with 16L, so they are just going along with the industry standard.

Greyhound wrote:

AutoSleepyDon wrote:I think it's a little misleading for AS to boast of a 25 litre tank then hide in the small print of page 7-5 of the manual that the float valve cuts off at 80% to allow space for the gas to expand so the maximum gas it can contain is 20 litres (as has been said already). It's a 20 litre tank in plain language.

It's a standard practice that tanks are only filled to 80% - my old VW T25 was exactly the same so nothing has changed in many decades.

Because most people know this, if they stated a 20L tank, people who know this would think they can only fill it with 16L, so they are just going along with the industry standard.

I agree that the max fill of 80% is standard practice. That is not unique to AS. But, is it standard industry practice to call a tank that can hold 20 litres of LPG, a 25 litre tank?

Isn't it industry standard to quote an LPG container in terms of it's LPG capacity rather than the volume occupied? e.g. a 6kg bottle of gas hold 6kg of gas (gas bottles also have the 80% max fill).

PS Yesterday at the motorhome show, the only other van I saw with an LPG tank was Murvi. I thought I would ask, out of interest, what the capacity was and they quoted it in kg 
I gather my Warwick Duos 25 litre tank, holding 20 litres of gas (and 5 litres of air), contains approx 10Kg of LPG. That's equivalent to a big (6KG) and a small (3.9KG) bottle.

I think if AS could call it a 10KG tank then that would be a fair compromise with my approval    or a 20 litre tank of course

AutoSleepyDon wrote:


I think if AS could call it a 10KG tank then that would be a fair compromise with my approval    or a 20 litre tank of course

But the flaw in your argument is that LPG can only be bought in litres and for a very good reason! 

The Ltr which is controlled under the SI system of units is the volume of a cube 10cmX10cmX10cm - this is the only way to regulate and ensure that you get the same amount from the pump each time you fill-up. 

As I understand it, (its a long time since I was in the school lab!!) but Pressure/Temperature (up a mountain or down at sea level - Boyle's Law I think) ) has an affect on a gas it would be impossible to accurately dispense the same amount each time by weight - this is why we also buy our fuel (Petrol/Diesel) by volume rather than weight.
I don't know why they sell the pre-filled canisters by weight - maybe because they are filled in controlled conditions and with a very accurate (before and after fill) weighing machine in the system - which of course would not be possible on a forecourt otherwise we would all be getting our vans weighed at the same time!!

Regarding the A/S stated tank size (I think you will find that A/S are only quoting the tank suppliers stated details) - is I believe to accommodate the 80% rule/regulations. In other words they have to quote the overall volume of the fitted tank and if it were to be tested from empty they could demonstrate that only 20ltrs would be accepted into a stated 25ltr tank. 
As you know this 20% additional space allows the gas to expand in the event of any ambient pressure/temperature changes - which can vary between 0 or below to in some place over 40C!
Liam

I always thought it was 20ltr, the practicaul Motorhome review of the 2014 Kemerton XL quote it as a 20 ltr underslung tank, and that’s what fits in
Problem solved, have fun

Liam wrote:Regarding the A/S stated tank size (I think you will find that A/S are only quoting the tank suppliers stated details) - is I believe to accommodate the 80% rule/regulations. In other words they have to quote the overall volume of the fitted tank and if it were to be tested from empty they could demonstrate that only 20ltrs would be accepted into a stated 25ltr tank. 
As you know this 20% additional space allows the gas to expand in the event of any ambient pressure/temperature changes - which can vary between 0 or below to in some place over 40C!
Liam

Quite correct Liam.

Contrary to what Autosleepydon said earlier, it is a 25 litre tank and it will hold 25 litres of liquid if filled to the brim. Therefore it is a 25 litre tank - Q.E.D.

If Messrs A/S referred to it as a 20 litre tank there would be other members on here complaining that it is in fact a 25 litre tank . . . . . . etc. etc..

Can't win, can they!!   Everyone who has read the blurb about any refillable tank will know of the 80% rule, so I can't see where there's a problem??

Gromit wrote:

Contrary to what Autosleepydon said earlier, it is a 25 litre tank and it will hold 25 litres of liquid if filled to the brim. Therefore it is a 25 litre tank - Q.E.D.

Yes the tank will hold 25 litres of liquid provided that liquid is cold tea or Beer etc but not LPG. When that liquid is LPG the capacity is 20 litres. A rather important consideration for an LPG tank. Therefore I contend it is a 20 litre tank. 
This standard is also adopted by Murvi and Practical Motorhome that I know of.

An alternative label for the 20 litre tank fitted by AS to van conversions is a 10kg tank.

Gromit wrote:

If Messrs A/S referred to it as a 20 litre tank there would be other members on here complaining that it is in fact a 25 litre tank . . . . . . etc. etc..

Can't win, can they!!   Everyone who has read the blurb about any refillable tank will know of the 80% rule, so I can't see where there's a problem??

I totally agree Dave - I just fill ours as I think it necessary, particularly if the fuel station has an LPG pump - not really bothered if its a little or a lot (the max I have managed to get in so far is 12 litres! We have been all through Europe and adopting the fill when you can philosophy, within reason, so far we have never run out of gas!

Some of the confusion over tank sizes may have arisen from the A/S brochure descriptions over the years, i.e. the 2014 brochure states "20 Litre Liquid Capacity LPG Gas Tank" whilst the latest 2017 brochure states (and probably legally more correct), "25 litre underfloor mounted LPG gas Tank". I believe A/S did increase the tank size in 2016/17 model range from 20 to 25 litres - so owners of newer models should get more gas into their tanks!
We have the original 20 Litre tank and it works fine for us and much better than lugging gas tanks around, making and breaking connections or finding storage for spares, worrying about being able to get the correct exchange refill, etc.. We carry the basic 3 Euro converter LPG connections (cost £19 at a show) with us in Europe and so far have always been able to fill up. 
The best modern recent addition to the Motor-home - IMHO.
Liam

AutoSleepyDon wrote:
Yes the tank will hold 25 litres of liquid provided that liquid is cold tea or Beer etc but not LPG. When that liquid is LPG the capacity is 20 litres. A rather important consideration for an LPG tank. Therefore I contend it is a 20 litre tank. 
This standard is also adopted by Murvi and Practical Motorhome that I know of.

An alternative label for the 20 litre tank fitted by AS to van conversions is a 10kg tank.

How do you come to that conclusion? Volume is volume, and if the tank will hold 25 litres of cold tea it will hold 25 litres of liquified petroleum gas - or any other substance for that matter.

Your maths seems a little suspect as well. This bit of illogic has me completely baffled, "An alternative label for the 20 litre tank fitted by AS to van conversions is a 10kg tank." ???

I still can't see what there is to complain about, specially since it has all been debated and explained many times over on this and most other motorhome forums.

A 25 litre water capacity tank (which is how the makers usually describe them) is allowed to contain only 20 litres (80%) of LPG, for safety reasons that I won't explain here. Seems pretty straightforward to me. 

AutoSleepyDon wrote:Yes the tank will hold 25 litres of liquid provided that liquid is cold tea or Beer etc but not LPG. When that liquid is LPG the capacity is 20 litres. A rather important consideration for an LPG tank. Therefore I contend it is a 20 litre tank. 
This standard is also adopted by Murvi and Practical Motorhome that I know of.

An alternative label for the 20 litre tank fitted by AS to van conversions is a 10kg tank.

Correct, but only if its a liquid that remains a liquid at ambient temperature!!!
But this is a gas that has been compressed (that's the way they make it a liquid) and for any given volume its capacity will depend on the ambient conditions. In some instance it will take up a larger volume then at other times - as I have described in my previous post.
Therefore A/S would have to say in their literature that the tank capacity could be between X and Y depending on a sliding scale of ambient conditions --- and I can see where that would lead in complaints from customers!
Liam

Thanks Peter.

Specsavers was closed when I went - or can I claim a "senior moment" now the ages are back in the profiles!!  

PLOUGHLIN wrote:
A litre of Liquid Propane weighs approx 0.5 kg. 20x0.5=10kg

Yes, that is how I see it too.

Also Justus2 raised a really good point about the blend of LPG which I had hoped to repeat but........
However, I gather LPG is 90% Propane in the UK.

AutoSleepyDon wrote:

An alternative label for the 20 litre tank fitted by AS to van conversions is a 10kg tank.

So, assuming one could purchase LPG by the Kg can someone tell me how do you monitor what you have remaining in your tank? 
Having dismissed the Ltr principal you cannot then have a gauge which measures volume (i.e. Ltrs) otherwise you are mixing apples and pears!! 
Go to the nearest weight bridge??
Liam

Bathroom scales Liam.

"But what about the tare weight?" I hear you cry! 

I think your earlier suggestion is the best I've heard so far, and it's what we do as well. Just top up whenever it feels about time, or when there's a pump handy.

Fortunately the gauges all seem to be fairly pessimistic, so there's usually more gas remaining in there that it shows on the dial.

I can beat you, but only just. When the gauge was down to 2 lights (mostly because I hadn't thought to look at it for a while) I still only got about 14 litres in. I don't think the gauge was ever intended to be spot on accurate, specially when considering how cheap it is, but when you are used to it's idiosyncrasies it gives a good indication when it's time to start idly looking for a garage with an LPG pump. 

Gromit wrote:Bathroom scales Liam.

Dave,
They would probably be just as accurate as the current gauge!!
Liam