Percentage or Miles/Kilometers : which do you use and why?

[darth_vad3r]

But those all those posts where people say they "only get z miles" are saying that they car only SHOWS z miles. They aren't drive testing the vehicle.



Ahh yes I love this one...so you have two variations here...
1) If rated miles actually changes with battery degradation(and SOC stays at 100% for full charge) then "120 miles" would be accurate(IAW EPA testing cycle), and SOC % would be BS

2) If rated miles still shows 310(or 325) at 100% SOC with battery degradation then both rated miles, and SOC are BS

So basically we don't know which is true BECAUSE I haven't seen the people who show less than 310(or325) at 100%, prove that they have actual degradation.

I argue against the SOC % until someone can show me that they car with battery degradation only charges to less tan 100%.

I'm not saying rated miles is perfectly accurate but it gives a better immediate value. Also, if at 100% SOC you show 310 miles, and at 50% you show 155 miles, and 25% it shows 77 or 78 miles, then it is being just as accurate as SOC%.

Right, so as you say (1) SoC % is BS, and (2) both are BS. Which one do you think Tesla would choose to display, total bs or partial bs? They are going to choose the more accurate one. SoC % is not bs though, because if you charge to “100%” of a degraded battery it is still at “100%”.

I haven’t seen anyone say “my battery only charges to 97%”. Good point as well.

 

[edigest]

I use percentage because, for me, only percentage matters on a trip. Around town, who cares? You're not going to drive around town until you get to a certain miles or percent left and then recharge. You're going to drive around town and plug in when you get home.

On a trip, I charge to the percent I want at the next stop. Pilots will understand this mentality. You put on the fuel you need plus your reserve. Nothing more; nothing less.

Don't have to figure out how many miles to the next stop and then add how many miles padding I want. Also, don't care what my battery degradation is 6-months from now. Just charge to 10% remaining at destination and go.

Using this technique on my trip this weekend I charged to what was needed for an arrival SoC of 10% and arrived with 11% to 14% at every stop.

 

[ucmndd]

Judging by the number of paranoid new owner posts asking why they drove 150 miles and used 160 miles of rated range, switching the display to percentage by default from the factory would be huge in increasing owner satisfaction and changing the way people think about range.

It also eliminates the paranoia around degradation.

Percentage FTW.

 

[Rocky_H]

How about three previous polls on this question? It'll save time.
Poll - energy or distance

Range or Percentage...a Simple Poll

State of Charge: Percentage or Distance?

 

[darth_vad3r]

My phone doesn't say hours, it says battery %.

I missed this the first time. This is a great example. Wouldn’t it be better if your phone did display “hours” so you could tell how much your 3-yr old phone’s “100%” was compared to when it was new? Of course you’d know that “12 hours” would vary based on how much you used it, but it would be more reliable over lifetime of the phone. On day 1 you could go from “24 hours” to “8 hours” on a typical day, and now when you charge to 100% you see “16 hours” ... you know that roughly you’ll still last all day. Once 100% is <16 hours you need a new phone, or use it less, or take a power bank with you or charge during the day. “Hours” is more reliable and useful than %. “Miles” is more useful than “%” in a car.

Laptops can change % display to h:mm, at least I know I’ve done this on a MacBook.

 

[cpa]

I use percentage when I am home, and when I drive to common destinations where I know how much battery I need to reach the next Supercharger or my destination.

When I am traveling to distant lands, I switch to mileage. I keep the end point handy in the navigation to show me the estimated percentage remaining in the battery when I arrive. This way, I can compare the initial estimate of reserve when I depart to the potential changes (better or worse) as I drive down the road.

It is much easier for me to compare the mileage signs along the road to the estimated mileage remaining in the battery. When the sign says that City X with the Supercharger is 108 miles away, it is comforting to see that the battery reflects 148 remaining miles. To see 58% instead (about what 148/256 on my '14 S85) would be meaningless. I am not smart enough to do the mental arithmetic to convert 58% to miles or 108 miles to percent in my head.

If the margin of error gets too close (for example, if the mileage display had been 125 miles), then I would keep the trip tab open on the touchscreen to keep instant watch on the percent decline and adjust my speed accordingly.

 

[ucmndd]

“Hours” is more reliable and useful than %. “Miles” is more useful than “%” in a car.
.

You make an interesting point but I think I still disagree. The problem is that “miles” or “hours” requires an estimated rate of consumption that may be wildly inaccurate based on current conditions. It’s particularly useless with a phone because time remaining is so incredibly dependent on usage (2+ days locked in pocket, maybe 2 hours playing Minecraft on full brightness).

On the other hand, if I’ve noticed I’ve consumed 20% of my battery in the last hour (or X miles), that’s simple and intuitive to calculate relevant real-time consumption and adjust if necessary.

 

[TT97]

How about three previous polls on this question? It'll save time.
Poll - energy or distance

Range or Percentage...a Simple Poll

State of Charge: Percentage or Distance?

Thanks for these. I had only voted on two of the three polls beforehand. Funny they got different results, I starting to think these polls aren't statistically accurate.

 

[Snow Drift]

I missed this the first time. This is a great example. Wouldn’t it be better if your phone did display “hours” so you could tell how much your 3-yr old phone’s “100%” was compared to when it was new? Of course you’d know that “12 hours” would vary based on how much you used it, but it would be more reliable over lifetime of the phone. On day 1 you could go from “24 hours” to “8 hours” on a typical day, and now when you charge to 100% you see “16 hours” ... you know that roughly you’ll still last all day. Once 100% is <16 hours you need a new phone, or use it less, or take a power bank with you or charge during the day. “Hours” is more reliable and useful than %. “Miles” is more useful than “%” in a car.

Laptops can change % display to h:mm, at least I know I’ve done this on a MacBook.

I guess, but since we get new phones each year, or so, it's not as important. Unless battery life drastically drops within 12 months.

So far, I'm not seeing a drastic drop in battery life from other owners. Tesla has a 70% warranty for 120k miles (or 8 years) on the M3 LR.

I have over 5k miles on our M3 and the SOC% and Rated Miles match a 310 mile range. (It did imbalance after we were charging under 90%, but then it fixed itself when we changed our charging habits).

 

[darth_vad3r]

BTW, lifehack to see both distance and percent ... use “distance” to see miles or km in main display, then nav to dest and leave the energy app “trip” screen up. The current % display on the graph is actually theoretically more accurate than the normal % display because you can, for example, see if it is “80%+” or “80%-“ based on where the current dot is relative to the 80% line

 

[darth_vad3r]

I guess, but since we get new phones each year it's not as important.

I'd really rather know based on my average usage how long it would last. That gives me an idea of how I utilize the energy. We all use the phone a different amount of time/different apps.

Ok, but you are adding a 3rd choice. “Your usage”. We are talking choosing between “%”, and “rated usage”. Given those two choices, and degradation/changes over the lifetime of a device, especially apparent in a phone, “rated usage” would be more reliable (aka “consistent”, “able to be trusted”).

The energy app shows a distance estimate based on last x, y, z distance of your actual driving, but that varies a lot so IMO it’s not a better choice since I’d be wondering how it’s detemining “my” usage and if it has adjusted recently or not. At least “rated” miles are consistent.

If I know it takes me 60 rated miles to drive 40 miles to work in the summer at my typical speed, but only 50 to get home, that should stay consistent. Then I can also calibrate expectations in the winter.

If it’s trying to be “smart” and adjust for my driving, what happens when I get back from, a long road trip and it has recalibrated? The numbers might be off.

Rated miles seems most consistent, reliable, trustworthy to me. They DO NOT equate to actual miles driven, but there is a relationship there that you can figure out for your use cases.

 

[Snow Drift]

I'd like to hear from someone with a lot of miles that doesn't have an imbalance. Did the car show less range due to degradation, or still show based on EPA.

My screen's SOC% = Rated Miles based on 310 miles, after 5k+ miles lifetime odometer.

 

[darth_vad3r]

You make an interesting point but I think I still disagree. The problem is that “miles” or “hours” requires an estimated rate of consumption that may be wildly inaccurate based on current conditions. It’s particularly useless with a phone because time remaining is so incredibly dependent on usage (2+ days locked in pocket, maybe 2 hours playing Minecraft on full brightness).

On the other hand, if I’ve noticed I’ve consumed 20% of my battery in the last hour (or X miles), that’s simple and intuitive to calculate relevant real-time consumption and adjust if necessary.

Of course people know that “hours” would be highly variable. Typically stats advertise massively different times for standby time, talk time, media playback time, etc. Everyone should know that “hours” will vary based on use. Same with “miles”. If you crank the heat and drive like a maniac your consumption will go way up. If you have no HVAC and are driving slow your consumption will be lower.

For 20% in the last hour of a trip you aren’t worried about degradation affecting your math for the next 20%, but if your commute takes “20%” in year one in the summer it might take “22%” in year 10.

But beside that, if you dislike the EPA’s estimated rate of consumption on “miles” why choose to do your own estimated rate of consumption on “%”? ... why not do the same with “miles”. Just think of them as “energy units”, not miles. I used 100 energy units in the last hour, I have 130 left, I might get down to 30 in an hour. You have more granularity with miles, even more with km, and you have the added side-effect that you can easily convert from energy units to distance because they are closely related.

 

[darth_vad3r]

I'd like to hear from someone with a lot of miles that doesn't have an imbalance. Did the car show less range due to degradation, or still show based on EPA.

My screen's SOC% = Rated Miles based on 310 miles, after 5k+ miles lifetime odometer.

How do you think average people without stats app or canbus access discover they have degradation?

If Tesla showed you a range of 310 miles at 100% SoC on a degraded battery I would say there would be grounds for a lawsuit.

 

[ucmndd]

But beside that, if you dislike the EPA’s estimated rate of consumption on “miles” why choose to do your own estimated rate of consumption on “%”? ... why not do the same with “miles”. Just think of them as “energy units”, not miles. I used 100 energy units in the last hour, I have 130 left, I might get down to 30 in an hour. You have more granularity with miles, even more with km, and you have the added side-effect that you can easily convert from energy units to distance because they are closely related.

Agree on this, they are both just “energy units”. I personally find energy units normalized to base 10 / percentage easier to mentally manipulate and infer real meaning from vs. some arbitrary conversion to distance or time. YMMV (pun intended)

 

[Snow Drift]

How do you think average people without stats app or canbus access discover they have degradation?

If Tesla showed you a range of 310 miles at 100% SoC on a degraded battery I would say there would be grounds for a lawsuit.

I hear ya.

 

[Rocky_H]

Agree on this, they are both just “energy units”.

They're not both energy units, though. The percentage is a "fullness" unit. Even if a battery has degraded to garbage levels and only holds half as much energy as it did when new, the battery will still report 100% full when the charging system has put in all the energy it is able to.

 

[Snow Drift]

They're not both energy units, though. The percentage is a "fullness" unit. Even if a battery has degraded to garbage levels and only holds half as much energy as it did when new, the battery will still report 100% full when the charging system has put in all the energy it is able to.

Will the Rated Miles decrease or continue to show the old range?

 

[jerry33]

Will the Rated Miles decrease or continue to show the old range?

Rated and Ideal miles decrease. The algorithm for miles remaining is something like current estimated usable kWh in battery times SOC% times Ideal or Rated consumption factor.

Edited for correctness.

 

[darth_vad3r]

They're not both energy units, though. The percentage is a "fullness" unit. Even if a battery has degraded to garbage levels and only holds half as much energy as it did when new, the battery will still report 100% full when the charging system has put in all the energy it is able to.

Right. It’s “fullness” or unreliable inconsistent energy units

I mean over one trip it’s consistent, but not over a lifetime.