Apart from the obvious of running out of gas is there any way of knowing how much gas is left in a bottle? I don't want to waste cash by exchanging the bottle if there's still a few hours of gas left!
Yes, I feel the same way - it's expensive enough without taking it back when it's not empty.
I carry a large bottle (CalorLite 6kg propane) and a small 3.9 propane as a standby for when I run out. I wouldn't have room for two of the 6kg bottles.
When I had a weeny campervan, I did the same as Francais above. The campinggaz bottles are a lot smaller, yet still seem to go a long way. You need different regulators for different types of gas.
Most garages etc.. sell Gas - i dont use the 907 as its too expensive - we have a 4.5kg gas bottle - give it a shake and if it sloshes around then its good for a weekend. The propane / butane 4.kg bottles are cheaper but heavier / more bulky to carry. Even when i run the fridge and the cadac or double grill off gas i use a gas splitter "T" piece and only carry one bottle.
You can buy a gauge which will tell you how much gas is left in the bottle or, get a gas bottle for a bbq they come in all sizes with a gauge on them,you only have to change your regulator.
To be honest,I wouldn't bother to much about getting a gauge because we've tried most,the magnetic type,a Calorlite bottle with in-built gauge and currently a Gaslow gauge on our 13kg bottle and none are what you'd call accurate..
The only real way to check,is to weight the bottle(..and subtract it from the empty weight..usually on the ali neck collar,in lbs and ozs).
We always have a couple of suitcase stoves with us for flexible cooking so we just resort to using one of these if the cannister for the double burner runs out and then source a refill the next day. Our gas cannister tends to last several seasons anyway before needing a refill so its hardly a hassle...
I like the hot water test though - just don't do it with the regulator fitted as that is supposed to be kept dry according to Calor.
------------- Love our set-up and need no more tents or gear, so trying to stop looking!
We carry two 3.9kg bottles in our folding camper as then can take one out to use with the Cadac and leave one to run inside the camper. unlikely both will run out together so usually a backup until you can refill