Having hard time using percentage over miles

[TomServo]

Why doesn't Tesla take the "mileage" number from the hidden Energy screen and place it by the battery ICON that is always displayed? Displaying the "EPA" estimate is goofy and servers no purpose given all the better data the car has.

 

[PACEMD]

I always take along a Cambridge University professor of theoretical mathematics as my navigator and guide. You know, so I can concentrate on not having to steer, change lanes, accelerate, brake, and such. "How we doin' Charlie?" As I stare intently ahead. "Talk to me Charlie".............Charlie is bent forward, chewing on what was once a pencil, frantically scribbling on his sleeve with only his brain........wild hair sidetracked on a peasant revolt.......

 

[PACEMD]

Oh, and I've tired professors of theoretical mathematics from other universities. Not worth it.......
I once tried a professor from the Sorbonne. Oh la la, what a disaster that was.........

 

[user212_nr]

I always take along a Cambridge University professor of theoretical mathematics as my navigator and guide. You know, so I can concentrate on not having to steer, change lanes, accelerate, brake, and such. "How we doin' Charlie?" As I stare intently ahead. "Talk to me Charlie".............Charlie is bent forward, chewing on what was once a pencil, frantically scribbling on his sleeve with only his brain........wild hair sidetracked on a peasant revolt.......

This...

After these last few comments the OP will be scared stiff to use percent.

 

[shinytop]

The energy screen (option) shows range left based on your driving and mine seldom matches the range on the battery icon. It is not unusual for energy screen showing range 50-100 miles more than the range above the battery icon. I have read many posts suggesting use of the % rather than miles. Not my cup of tea but good for those who believe it works for them.

 

[noshadow]

The majority of my driving will never take me very far. To me, the battery indicator is really just to let me know when I need to charge the car, kind of like when I need to fill up a gas tank on an ICE car.

On longer trips (over 50 miles) I'll always use ABRP or something similar just to make sure.

I feel like it's almost a non-issue to think about the charge at all until I go on a longer drive, and in those cases, just let ABRP do the thinking and planning for me.

I switched to miles a couple days ago, and I realized that I was then trying to think about what the percentage was, because I had gotten use to that. LOL.

 

[hgmichna]

I wish the mile display would always use EPA or WLTP ratings, but it obviously doesn't. My miles display varies widely. I don't think my battery has already degraded by 12.5%, and neither does ABRP, which estimates a degradation of 1.2%. So the miles are rather unreliable.

Percent, however, is also, even more, meaningless, because when you change between Tesla cars, let's say between an SR+ and an LR car, the percentages tell you nothing about how far you will be able to drive. You have to have your battery capacity and your consumption in mind and calculate all the time.

I wish the car would always simply display the miles according to either EPA or WLTP, because then I could simply say, I will in normal road conditions be able to drive this far at 65 mph. Lacking this I would at least want to know how those miles are calculated, i.e. what they actually mean. But nobody knows, as you can discern from various discussions around here. Tesla doesn't tell. I wonder why not.

The miles display comes closer to this ideal, so I will probably switch to miles (or kilometers in my case) again, which I had already used for a while with reasonable results. The only time I would prefer percent is when setting the charge limit. I'll miss that.

 

[spokey]

I think there should be an option to remove it entirely with just a pop-up if the car thinks you're getting uncomfortably low.

In a gas car where you usually start the day with the gas tank at a randomly non-full state it is very easy to run out of gas if you don't have a gauge constantly reminding you of the fuel remaining.

But in an electric car, most people will be plugging in every night in their garage. So every day you start with a full battery. Unless your daily commute is pushing the limits of the car's range, there is no need to ever look at the battery gauge on a normal day.

You'll want to pay close attention to your state of charge on road trips, but the rest of the time the battery gauge is just clutter on your screen.

Our '59 Volkswagen Microbus didn't have a fuel gauge. Never ran out of gas

 

[frankvb]

I wish the car would always simply display the miles according to either EPA or WLTP, because then I could simply say, I will in normal road conditions be able to drive this far at 65 mph. Lacking this I would at least want to know how those miles are calculated, i.e. what they actually mean. But nobody knows, as you can discern from various discussions around here. Tesla doesn't tell. I wonder why not.

It does, however there is one (massive) caveat. It shows the EPA range remaining for what the BMS thinks is your current battery capacity.

It's clear that the BMS can be off a lot. For me e.g. it's showing 301 miles for 100% battery, and there is absolutely no way that my battery has lost 7.5% of its capacity after 3000 miles (326 would be shown with 0% degradation).

BTW: my current average consumption (mix of city and freeway) is around 300 Wh/m, so the real range is around 250 miles. Easy to display the battery percentage and multiply by 2.5. And for road trips just rely on ABRP and/or the built-in navigation.

 

[popc0rnx]

Look at it this way, do you set your phone to show how many hours of run time it has left?

 

[spokey]

Look at it this way, do you set your phone to show how many hours of run time it has left?

Makes no sense to look at it that way. Apples and Pears

1. My phone doesn't go from 100% to 0% by using it for 5-6 hours
2. My phone can be charged almost anywhere I am. And if I think I'll be somewhere where I can't (say camping), I bring a battery pack that will give me hours of use until I can get back to civilization to charge.
3. The consequences of my phone charge going to 0% is (generally) of little significance. Not true of my car.

The closest SC is about 15 miles. The closest level2 is 5 miles and only open at certain times (closed all today for instance)

 

[masotime]

Look at it this way, do you set your phone to show how many hours of run time it has left?

My phone can be charged almost anywhere I am. And if I think I'll be somewhere where I can't (say camping), I bring a battery pack that will give me hours of use until I can get back to civilization to charge.

This is the most critical point. There’s no practical way to charge the car if you aren’t near a charging station and you run out of energy. With a phone power packs are both portable and aplenty, which makes running out of battery on a phone far less inconvenient.

 

[Raechris]

I'm having a hard time using the percentage left. I'm constantly trying to do the calculation in my head of miles. I know everyone talks about using percentage and how it's better, but it's just such an arbitrary number to me still, even at about 3,000 miles driven on the car.

I know the mile range is an estimate, but it seems to be better than the estimate I can come up with in my head while driving.

Does anyone have thoughts about how I can think about percentages better? How do you do it?

Think of your smart phone, it doesn't tell you minutes left. The miles remaining is great but not indicative and can be disconcerting when climbing a hill to watch miles drop off quickly. Use nav and you will always know remaining at destination. Follow energy graph during trip mode. Finally each 10% = 30 miles range

 

[PACEMD]

Look at it this way, do you set your phone to show how many hours of run time it has left?

No, I set mine for miles of run time...........

 

[jcanoe]

Our '59 Volkswagen Microbus didn't have a fuel gauge. Never ran out of gas

Our '58 Beetle did not come from the factory with a fuel gauge; my father had an aftermarket fuel gauge installed that would sometimes get stuck so you never knew how much fuel remained. I would just keep track of the miles I had driven, fill the tank about once a week or every 200 miles. The '58 Beetle had a fuel reserve feature. You would drive until you sensed the engine begin to be starved for fuel, then use your foot to flip a lever located in the driver's foot well near the clutch, brake and accelerator pedals to the right (I have forgotten the exact location of this control lever.) This lever, normally in the vertical position, would control a valve within the fuel tank. The valve controlled the flow of fuel from two feeder pipes; one being taller than the other. When flipped to the right the valve would allow fuel to flow from the shorter pipe that accessed fuel from lower down in the fuel tank. This lower pipe provided access to an additional ~1 gallon of fuel and approx. 25 miles of driving range. After filling the Beetle's fuel tank (8.5 gallon capacity as I recall) you had to remember to flip the fuel reserve lever back to the upright position or else the next time you ran out of fuel you would have no reserve.

 

[spokey]

yeah, that's pretty much the bus. We were told it's 'reserve tank' was actually a flapper in the tank that held up that gallon, but maybe that was a tale for we country bumpkins. Our lever pulled out from kind of below the seat. Right in the middle behind the shift lever is how I recall it. Just a rod with a knob I guess connected via a cable to the tank. And yes, there were a couple cases of being stranded for not pushing the lever/rod back in when filling. Fortunately there were plenty of super chargers gas stations near by.

We bought this sort of manual odometer from (I think) JC Whitney. It was maybe an inch high and 3 or 4 inches long. Had 4(5?) wheels with digits 0-9. A little window at the top of each disk let you spin the wheel and 'set' a digit displayed in the window. Interesting that we also used 200 miles. So we'd take the current odo, add 200 and set this manual odometer thing. True you'd have to subtract to get your remaining miles, but it worked. Also had two little spring clips on the back. I think we had it clipped to some vertical slots/vents to right of the steering wheel.

The '63 beetle had a gauge. Thoroughly modern except of course for no heater fan. Could get pretty nippy sitting at a light in the dead of winter.

 

[filotej]

I learned to drive on my grandfather's beat up 1965 Toyota Crown. Fuel gauge didn't work so I used the midrib part of the palm leaf as a dipstick to measure how much fuel left. Gas was measured in inches.

 

[GlmnAlyAirCar]

I know everyone talks about using percentage and how it's better, but it's just such an arbitrary number to me still, even at about 3,000 miles driven on the car.

Percentage is not better. In fact, it is objectively worse. It throws away information and leaves you less certain as to the amount of energy in your battery. Those who advocate percentage often knowingly accept this loss of information in order to provide a degree of separation from "range anxiety." It's akin to burying your head in the sand, and most of the time it works out ok. If you're alright with this, go ahead and use percentage.

Rated miles are directly proportional to the amount of energy in your battery. For each model of car, the constant varies but for an individual model it is always the same. For my car (2015 S 70D), the factor is 290wh/mile. Multiply this by the number of rated miles shown, and this is the amount of usable energy in wh. Simple.

Now, think about percentage. Your battery contains a certain amount of energy. If you knew what this number was, percentage would be useful, because you could simply multiply and find out how much usable energy remains. But you don't know this (at least not without some careful measurements that involve using....rated miles). So with percentage you are simply guessing how much energy you have.

Percentage is worse. Objectively.

 

[jcanoe]

Percentage of battery charge remaining works just fine for me on my iPhone.

 

[nyghthawk]

I'm having a hard time using the percentage left. I'm constantly trying to do the calculation in my head of miles. I know everyone talks about using percentage and how it's better, but it's just such an arbitrary number to me still, even at about 3,000 miles driven on the car.

I know the mile range is an estimate, but it seems to be better than the estimate I can come up with in my head while driving.

Does anyone have thoughts about how I can think about percentages better? How do you do it?

I don't know if this was said, but I think of it this way.

In an ICE car, you have your FUEL Guage. It is

E ' ' | ' ' | ' ' | ' ' | ' ' F

This never tells you "you have 350 miles left" or "125 miles left" it tells you
You have Full Tank (100%), 1/4 tank gone (75%) or you are running on E "5%<" etc etc.....

I know modern cars have "miles left", but I have seen/used that and it says "60 miles left" I drive to the next light (300feet) and it goes down to "50 miles left". So you cannot follow that. So why does having "miles left" matter? It is an arbitrary number that should never have been included. It was only included to SHOW the EPA range etc......

When I am down to whenever my "yellow light" turns on, I know I have about 2 gallons left. I know my "average" mpg, so I "know" how far I can drive, REGARDLESS of what my ICE CPU is telling me.

So if I can figure out that 5% uphill gets me 20 miles that is essentially my "mpp" or "miles per percentage".

I hope this helps.....