1kg of LPG equates to 1.96 litres of LPG at 15degC (fuels including LPG expand and contract with temperature changes, 15degC is the temperature at which pumps for petrol, diesel and LPG are 'normalised'). This means that there are 92.1 litres of LPG in a 47kg bottle.
I charge £2095 to convert Elgrands, £375 for the pump.
Usually an LPG tank will only allow you to fill it to 80% of capacity, this allows for a 20% headroom to allow for expansion of the liquid gas in case the tank is heated after filling. The fill limiter is automatic and works like a toilet cistern fill valve (when it rises on the liquid it closes the valve which stops any more gas entering from the pump), you don't need to worry about overfilling the tank because fill limiter is automatic. The 20% headroom is unnecessarily excessive so I modify the fill limiter on tanks I fit to allow them to fill to 90% of capacity, which gives gains of 10% capacity and range. I fit the biggest tank that will fit on Elgrands, this has capacity of 93 litres so would normally allow filling to 74 litres at the usual 80% limited capacity but allows filling to around 84 litres with the 90% fill limiter modification. I not only fit a bigger capacity tank than competitors but am also the only installer to do the 90% mod, the combination means Elgrands I convert have much better onboard capacity and range on LPG than competitors conversions.
If the Elgrand tank holds 84 litres of LPG and the red bottle holds 92.1 litres you can work out that the red bottle has enough gas to completely fill the Elgrand tank and still leave some gas remaining in the bottle. No problem, you could use a bit of gas from the vehicle full tank then pump the remaining gas from the red bottle into the vehicle tank. Or (though I haven't bothered myself) keep 2 red bottles, fill the vehicle tank when it's empty, next time you come to fill pump the remaining gas from one bottle into the vehicle first then pump some gas from the full red bottle into the vehicle tank. Order another red bottle as soon as you've emptied one and there'll never be a time when you don't have some gas at home to pump in.
There are a few types of LPG tank, by type I don't mean dimensions or capacity I mean design. Full toroidal (shape) tanks are fitted at the ELgrands spare wheel position. Of full toroidal tanks the vast majority are single hole, meaning they have a port to connect a single large valve block, the valve block has the output port that feeds the engine, the fill port, the fill limiter is built in, safety measures such as a pressure relief valve and thermal fuse are built in. Single hole tanks have an inlet port to accept an 8mm pipe, which seems narrow but the gas is forced in through pressure. Even at the higher pressure the 8mm fill port does slow filling compared to a different design called a 4 hole tank design. As you might expect 4 hole means there are 4 holes in the tank, one for gas inlet, one for a combined pressure relief valve / thermal fuse, one for the gas level sensor float, the other the output that provides gas to the engine. The 4 hole design uses a 12mm inlet and can fill at the same speed as filling with petrol but the 4 hole design are far more expensive and not often available. I am probably the only installer who has ever fitted a 4 hole tank on an Elgrand, only a few customers have been willing to pay the extra hundreds of pounds.
The pump I sell is slower than filling at a forecourt, it pumps at 3 litres per minute so takes 28 minutes to fill the 84 litre working capacity tank from empty, but you can be at home having a coffee etc while it's pumping.
