[eluded]

I filled up a few miles after the range went to ----

Added 14.8 gallons into the 15.8 gallon fuel tank.

[xlover]

Bit of a buffer... what else is new

[donkey]

Only problem I see is you're not in sport mode

[reyoasian]

Range is based on your driving style for the last 20 miles

[Billfitz]

Originally Posted by reyoasian

Range is based on your driving style for the last 20 miles...

The sample rate is much higher than that as you approach an empty tank. The only time I ever got below 50 miles remaining was in hill country, where after going uphill the range estimate dropped very low, due to the high rate of fuel consumption going up the incline. Coming down the hill on the other side the range estimate literally doubled. It repeated this pattern, with the range fluctuating from around 10 miles to around 40, updating the results every mile or less. The updates were much more frequent when going up or down a hill than when on a flat stretch.

[SsixHiMod]

been there

[HighlandPete]

Originally Posted by Billfitz

The sample rate is much higher than that as you approach an empty tank. The only time I ever got below 50 miles remaining was in hill country, where after going uphill the range estimate dropped very low, due to the high rate of fuel consumption going up the incline. Coming down the hill on the other side the range estimate literally doubled. It repeated this pattern, with the range fluctuating from around 10 miles to around 40, updating the results every mile or less. The updates were much more frequent when going up or down a hill than when on a flat stretch.

Yeah, a rolling calculation, ('during' the last 20 miles driven), seen it continuously adjusting and updating the range in all my BMWs.

Typically in my 535i, I'll lose 6 miles from a cold start for the first 3 miles of driving, then gain up to 12 miles on an easy drive for the next 9 miles down to sea level. Coming home is different, can lose 20 miles, driving 12 miles.

Filling at the end of the outward journey gives a superb range on a full tank.

One of the best was with the 540i where it could swing dramatically from free running to stop-start traffic.

Say it was indicating a range of 80 miles, a bit of heavy stop-start traffic and it could drop by up to 60 miles in a couple of miles. Then when free running again, back up to ~75 miles range.

[Wires]

It's how mfr's avoid backlash from drivers expecting exactly the mileage shown the display.

Just a FYI though... running the tank that low causes the in tank fuel pump to run hot which eventually destroys it.