Just bought our FL2 and came from the dealer with a "full tank" and OBC saying range of 385 miles. Two things I thought - 1) it probably isn't really quite full 2) been on a load of short runs around the dealer, so it's using the last "n" miles as it's reference. Because 385 range is 26MPG for a full tank.

So yesterday we went on a 425 mile round trip and got back with range showing 50 miles left. Computer said we averaged about 36mpg, so this is all consistent. So when I re-filled, I expected the range to show about 550. But no, 385 again !

Is this normal?

(MPG looks fair given the values in the MPG thread - auto sD4, Cruising in lane 3 with the rest of 'em (70 mph that is))

not sure if its normal but my DTE when filled sohws 999kms. Every now and then it itself and indicates something else but I don't worry about it. Sometimes the gauge only reads 1/2 full but sorts itself out in time, if not, I pull the + lead off the battery to reset and all is good.

g

Did you reset the trip before leaving fuel station?
If so distance to empty will be calculated on the short trip from the time
You leave service station to the time the trip has collected enough info to set parameters in trip. Will show "--" in
Display until such time it has calculated variables and is based on that short trip. MY15
Tyre Pressure Monitoring System (TPMS)
Surround Camera System
InControl Apps soon to be replaced with CarPlay (WIP)
Meridian Premium Surround Sound
Digital Audio Broadcast
Timed Climate
Cruise ECO Data
Follow Me Home Reverse
Extra Features Menu
Picture In Motion
4x4i screen (WIP)
Digital Broadcast TV
Meridian Rear Media with WIFI
Factory Powered Tailgate
Blind Spot Monitoring (BSM)
Reverse Cross Traffic Alert (RCTA)
Electrochromatic Wing Mirrors (WIP)

Mine being petrol, I carry around a handful of spare 10L tanks!

Click image to enlarge

There are too many unknown variables for it to give anything more than an approximate estimation. These include; no actual measure of the amount of fuel put into the tank, fuel slopping around in the tank making it difficult to estimate the quantity, historic mpg achieved and current mpg which of course is also very variable depending where when and how you drive. I've had mine running when the indication has fallen below zero but I usually fill up until the pump stops when the fuel gauge shows 1/4 full. One one recent fill it indicated around 390 miles but after a 10 or so miles on a really easy run it went up to over 600 miles. Once back to normal driving and traffic it went baack to the usual indications.

J

as with anything else in this technological era such as various apps on phones etc... they are just really intended as a guide and not intended to be taken as 100% true. But everyone thinks they are totally accurate. The same goes with range calculators on all cars now.

My old Vauxhall Antara (please don't slate me too much ) showed as having IIRC 360 miles range when I reset after filling up and before I pulled away from the pump to start a drive from Mansfield to Newquay. The car was fully loaded with 2 adults, camping gear, roof box, and dog in the boot.
When I arrived at the campsite several hours later the range was showing 420 miles IIRC.......

The trouble with all these "predictive" features, is that unless you know and understand how their calculations are made, they are virtually useless. I find the ETA feature on the satnav annoying as it seems to factor in your journey to date as well, which might seem like a good idea, but just complicates things so much that you are better making your own judgements

I suppose the "range" feature is more use as you get towards the end of your tankful. I have never really bothered with it after filling

Steve

common sense to be applied at all time I guess. Do you really want to turn right down that 1 way street because your sat nav tells you to? do you really believe that there are actually only 5 miles left in your tank but its only 2 miles to the nearest garage so you don't worry ?

I never take these as gospel, but in my 5 series, it takes a much more long term view, so while it can clearly vary and be wrong, especially if you move from short to long journeys and vice versa, in doesn't adjust wildly.

Just a question of getting used to it, but your answers have been helpful as it seems to be more short term and more based on the usage since you started rather than, say, the last 500 miles.

It is more useful at the end of the tank and was reasonably accurate assessing what fuel was left when I filled up - I don't like visiting fuel stations so I like to leave to under 50 miles to go, but in our Astra, for example, this is a risk - and it has run out twice before the estimated miles gets to zero - once queuing for the pump, luckily and once not so lucky, 3 miles out. (20 miles to go showing that time!). That now gets filled up at 50 to go and we carry a can in it. Whereas my 5 series I can happily run to zero, knowing I have at least -50 miles on their estimate, always. Knowledge is power.

Lightwater wrote:

Mine being petrol, I carry around a handful of spare 10L tanks!

Click image to enlarge

When I fill up at my local station & reset the data when I get home the figures are off the chart due to the very short trip. Most trips are short, together with waiting at intersections, hills & AC the car uses a fair bit!

Same with mine, it has only once gone above 385 range to 420 for a very short time, where as on a VW Passat estate I once owned was very accurate to within 20 miles distance covered to indicated start range. REME .. Rough Engineering Made Easy

Been shopping; had been parked for over an hour in a nice flat car park, got back in the car and started the engine and the range indication was 398. Was about to start off when SWMBO "lost" something and had to search her handbag before I was allowed to set off. So I sat there for over ten minutes with the engine running (I know I shouldn't have left it running but it was the only way to show I was ready and we were wasting time) and during this time the range indication increased several times eventually getting to 409. Eventually we set off and everything worked as normal with the range indication falling by about 30 miles over the journey home which was 30ish miles.

If anyone is interested I don't know what was lost in the depths of the handbag or if it was ever found.

J

The algorithm is as follows:

Average Fuel Consumption
Every 200 meters of vehicle travel the instrument cluster re-calculates amount of usable fuel in the tank to determine how much fuel has been used.
This value is then averaged over the last 31 miles (50 kilometers) of travel and displayed in the trip computer.

Range
The range value is calculated using the average fuel consumption value (see above) and the fuel tank level value.
By dividing the fuel tank level value by the average fuel consumption value, the instrument cluster can calculate the distance the vehicle can travel with the current amount of usable fuel in the tank.

Thanks all - the last post sounds highly plausible - it's very biased towards recent consumption rather than, say the last 100 or 150 miles. Pro's and cons, but the main thing is 1) to understand it and make best use of it, knowing it's limitations 2) I know it's not faulty.