Neither, at least on my Forester. I only use trip A, and I reset it at each fill-up (habit from a prior car that didn’t have a working fuel gauge), and yet I see the behavior I described on the range estimation. If it relied on the trip odometers, I’d see a consistent range after filling up.
Maybe it’s fuel economy over the prior 500km or so?
I had a Subaru guy tell me that the low fuel alert is volume-based, the equivalent of the reserve amount below “E” on some cars years ago. Indeed, sometimes I’ll get it before the range dips to 60, and sometimes a couple of miles after it reaches 60.
I want to say the low fuel alert more reliably coincides with being on the last block of the fuel gauge display, but since I tend not to go below a quarter-tank, that’s not something I’ve extensively tested.
Yes, that’s the conclusion I would reach from the owner’s manual, but in practice I observe close correlation with 60. Has it ever been before 60? Quite possibly, but I haven’t taken notice of it. Has it reached 60 without the light turning on immediately. Definitely, but usually not much delay, and I don’t think it’s ever reached 50 (and steps are 10).
I never intentionally switch between A and B, but sometimes do it carelessly when intending just to reset it. And again, reset is based on a prior car.
Nothing in the manual indicates the driving range is based average fuel consumption rate for the most recent _ distance, but it does say (in the section where it talks about different rates for A meter and B meter) that the average is not calculated until the car has traveled at least 1 mile (or 1 km) since the odometer was reset.
I’ve had the low fuel idiot light come on while showing a range of 70. It was on before getting to 50.
It’s probably a trigger in the 7-8 liter range.
This reminds me of one annoyance I have with my Forester’s fuel and temperature displays – I can’t switch between metric and American customary units. That complicated my effort a few years ago to train myself to think in metric as well as American customary.
Checks out.
I’m still figuring out my wife’s car’s range. Instead of beating it, the range number ALWAYS drops faster than how far we’ve driven. I’ve overfilled it and it comes up with 400+ miles in range, only for us to to get a "Miles Driven Plus Range To Go "around 350 or so. So, it knows how much gas is available at the start, and optimistically sets the range based on 45MPG or so. “Sure, you will drive the speed limit and go downhill both ways (it’s a hybrid).”
So, I give it a +/- of 10 miles.
I’ve also dropped it to 0 miles left. Still drove
When I turn on cruise control, it seems like the miles remaining drops incredibly slowly and then I turn it off and it seems to recalculate a new lower value very quickly.
I was using cruise control after the first 20 miles of the trip (and likely using it 0 during the original 215 miles on the trip odometer.
FWIW, I did not note the gas remaining number until odometer was at 260, so I don’t know if it was constant at 150 for 45 miles. (My guess is probably not, since it likely dropped driving about 15 miles averaging 40 on the interstate, even if no stops. And there was about 3 miles, with some traffic lights and even a stop at a store, before reaching the interstate.)
My Mazda always overestimated MPG by about 3, so the stated range was similarly off. My BMW was quite good at estimating by MPG, usually about +/- 0.5. My Tesla is dead accurate, zero miles on a gallon of gas.
But how is your Tesla at estimating the miles until it’s out of charge? Seems like that would vary a lot more than gasoline since it’s even more sensitive to factors like outside temperature and use of climate control features that ICE cars are.
I’m sure it’s accurate, but that is not the MPG number it would come up with.
Let me check my Excel… #DIV/0!
Now, as twig is asking, what about the range estimate, which is what is being discussed?
So you put in your destination, and it’ll tell you where to charge and how much battery you’ll have at each stop. Or if it’s a short-ish trip it’ll tell you your estimated charge upon arrival. I haven’t done any cold weather testing yet. Thus far it’s accurate usually within 1%, sometimes 2%. 2% is about 5-6 miles of range, which I’d call pretty good.
Does it not give you a range estimate? I mean, on a typical Saturday I probably have 6 or 8 destinations and I don’t want to fuss with inputting them all. When I’m on errand 5 of 8 I want to know if I have 100 miles to empty or 20.
It will, I have it set to % rather than miles but it’ll show miles. How accurate that is depends largely on city vs highway driving. I think it uses the EPA number to guesstimate range for this display.
I wake up every day with an 80% charge (160-240 miles) and don’t normally drive more than 60-80 miles and that’s if I go to Costco in Kansas City. Range only matters on road trips. Assuming you can charge at home.
Battery chemistry. Most batteries don’t like living at high states of charge, it degrades their capacity. Some batteries can be routinely charged to 100%, but I’ll get more longevity by charging daily to 80%, and only going to 100% for road trips.
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