When the battery is charged to 100%, why doesn't miles remaining give the full EPA range?

[doubletwist]

I don't see how doing math in your head is relevant. The miles that the car shows are not the miles you can travel. You surely need to be able to do some math in your head to estimate how far you can go from the EPA miles you are shown.

As it currently stands, yes, but that's why so many people would like a more accurate estimate of miles remaining.
Nobody expects it to be perfect, but other vehicles are capable of at least having a reasonably close estimate that adjusts for recent efficiency as it gets closer to empty. Even cheap cars have had that capability for decades, so it's not unreasonable for people to hope for that same capability in their high-tech $70-120k+ car.

Can I do it in my head? Yeah, sure but it's annoying and I'd rather let the expensive computer do the math (it's kind of what computers are for!) while I focus on the road ahead of me and enjoying my drive.

Again, just because YOU can do it easily in your head doesn't mean that everybody can.

 

[DeaneG]

As it currently stands, yes, but that's why so many people would like a more accurate estimate of miles remaining.... it's not unreasonable for people to hope for that same capability in their high-tech $70-120k+ car...

Gravity has a much-improved range estimator. We can hope that it will come to the Air some day.

 

[bfab]

I don't understand why people use the "miles remaining" configuration when it is nowhere close to reality anyway. Just switch to percents and stop worrying about that nonsense.

Some people have difficulty doing math in their head.

And before any snarky comments are made, it's NOT about intelligence. different people's brains are good at different things. For some people, mental math just isn't one of them.

Folks, I am just trying to understand how my new Lucid works vs the Bolt I've been driving for 7 years. The reason people use "miles remaining" is because people want to know whether they can cover a trip of a certain distance, not a certain KWh. And experienced EV owners realize this is an approximation given the impact elevation changes, weight, wind, temperature and other factors that contribute to energy use.

And as for the math comments, I work in a technical field and would do fine on any math test, such that I don't need to make comments that put down other people in order to raise my own status up.

 

[bfab]

As it currently stands, yes, but that's why so many people would like a more accurate estimate of miles remaining.
Nobody expects it to be perfect, but other vehicles are capable of at least having a reasonably close estimate that adjusts for recent efficiency as it gets closer to empty. Even cheap cars have had that capability for decades, so it's not unreasonable for people to hope for that same capability in their high-tech $70-120k+ car.

Can I do it in my head? Yeah, sure but it's annoying and I'd rather let the expensive computer do the math (it's kind of what computers are for!) while I focus on the road ahead of me and enjoying my drive.

Again, just because YOU can do it easily in your head doesn't mean that everybody can.

Yes, my Bolt surprisingly did a number of things better than the more expensive Lucid, including this. It also had great energy usage pie charts and bar charts to distract me while driving around. The Lucid has a big, dumb dial and no numbers so far as I can tell, unless I'm missing something as a new user. The energy data interface seems designed for people who don't want to get into the details.

 

[msaunders9430]

Another reason I prefer "percentage" is for normal around town use, I try to stay within the 30% - 80% SOC recommended in the manual. Doesn't always happen. Same when needing to DCFC (around 20% SOC recommended).

 

[knewman]

Yes, my Bolt surprisingly did a number of things better than the more expensive Lucid, including this. It also had great energy usage pie charts and bar charts to distract me while driving around. The Lucid has a big, dumb dial and no numbers so far as I can tell, unless I'm missing something as a new user. The energy data interface seems designed for people who don't want to get into the details.

This is something I really dislike about my Lucid. All the interfaces are so abstracted and smoothed down that we're left with very little real information. At least they left the API open for us to query (although I bet this is going to get cut off someday).

 

[tarator]

Folks, I am just trying to understand how my new Lucid works vs the Bolt I've been driving for 7 years. The reason people use "miles remaining" is because people want to know whether they can cover a trip of a certain distance, not a certain KWh. And experienced EV owners realize this is an approximation given the impact elevation changes, weight, wind, temperature and other factors that contribute to energy use.

And as for the math comments, I work in a technical field and would do fine on any math test, such that I don't need to make comments that put down other people in order to raise my own status up.

Since it is an approximation, how can you depend on what you see? If I wonder if I can get to a place, I always plug the address in one of the apps that can calculate the mileage much more precisely than the EPA value.

I have no idea why that guy started talking about doing math in your head. I probably can do that well, but I don't, at least for mileage estimation.

 

[j4gates]

thats interesting! flies in the face of the general advice to keep the car in the 20-80% range with ~50% being the optimal for longevity.

This recalibration, does it only account for how the BMS reports the capacity or does it actually extend the longevity. I personally have near 30K and i'v seen my 80% capacity drop from 336 when new to now 331. not enough for me to act on as its about 2% over 20 months, but enough for me to be be curious.

I'll preface by conceding I'm not an EV or battery nerd, but I do watch channels like Kyle @ OoS . The recalibration concept came from one of those channels.

From what I recall, after many charge/discharge cycles, the BMS loses the bubble on the HV battery's capacity calculation. My guess (purely a guess) is that the calculation uses only 1 or 2 digits after the decimal point and rounds the actual numbers. Over time the rounding error compounds and the BMS no longer has an accurate yardstick for the battery.

I would just add more speculation as to what actually occurs by allowing the car to "sleep" at a low SOC prior to running it through a full AC top off, but my general thought is it simply forces the BMS to realize the math is off and it needs to reset the calculation cycle.

All that said, this would only be something you'd do every few years if you care enough...not something to do weekly or monthly.

 

[skomarla]

I'll preface by conceding I'm not an EV or battery nerd, but I do watch channels like Kyle @ OoS . The recalibration concept came from one of those channels.

From what I recall, after many charge/discharge cycles, the BMS loses the bubble on the HV battery's capacity calculation. My guess (purely a guess) is that the calculation uses only 1 or 2 digits after the decimal point and rounds the actual numbers. Over time the rounding error compounds and the BMS no longer has an accurate yardstick for the battery.

I would just add more speculation as to what actually occurs by allowing the car to "sleep" at a low SOC prior to running it through a full AC top off, but my general thought is it simply forces the BMS to realize the math is off and it needs to reset the calculation cycle.

All that said, this would only be something you'd do every few years if you care enough...not something to do weekly or monthly.

Good to know. I’ll try it soon ovet the next few weeks and see if it helps at all.

 

[DeaneG]

From what I recall, after many charge/discharge cycles, the BMS loses the bubble on the HV battery's capacity calculation. My guess (purely a guess) is that the calculation uses only 1 or 2 digits after the decimal point and rounds the actual numbers. Over time the rounding error compounds and the BMS no longer has an accurate yardstick for the battery...
All that said, this would only be something you'd do every few years if you care enough...not something to do weekly or monthly.

It's because you can't determine precisely the state of charge of an NMC cell simply by measuring its voltage and temperature. BMS systems also monitor charge going into the battery and leaving. Some energy is lost to heat in the battery during charging and discharging, which is also modelled (estimated) by the BMS. As all of the measurements and models are fundamentally integrated into an estimate of the state of charge of the battery, small errors accumulate with time. Only by resetting the integration (going near 0% and/or 100%) can you come back to a present approximation of reality.

 

[bfab]

My understanding is that the miles remaining calculation is based on the actual energy the battery contains, not its charge percentage. I could be wrong.

The car's battery management system (BMS) keeps careful track of how much energy (kWh) goes into and out of the battery. It also knows the voltage of the battery's cells. With both of these, it can estimate the battery's total capacity and current state of charge.

This estimate may fluctuate up and down. A 6% loss after one year is higher than you'd expect for a modern EV. You could always ask your service center if anything is wrong.

EV Battery Health: Key Findings from 22,700 Vehicle Data Analysis | Geotab

Analysis of electric vehicle battery health of 22K+ EVs reveals a 2.3% average battery degradation rate. High-power DC fast charging is the top risk factor.

www.geotab.com

Forgot to say thanks for this explanation - I at first had the impression from discussions of this topic that miles remaining had no relationship to any actual measurement, but it sounds like that's not correct. I am following up with my service center....

 

[Aka-none]

If you want to get deep into the details of battery technology. Try cruisers forum and get to the systems posts. That site is where people live based on state of charge, how to measure it and what it really means.

 

[Adnillien]

If you want to get deep into the details of battery technology. Try cruisers forum and get to the systems posts. That site is where people live based on state of charge, how to measure it and what it really means.

Could you post a link to it? It sounds interesting.

 

[Aka-none]

Could you post a link to it? It sounds interesting.

Here is the root forum for lithium based systems

Lithium Power Systems - Cruisers & Sailing Forums

Lithium Power Systems - Lithium is a great option for extended life, energy dense charging systems.

www.cruisersforum.com

There is a lot there but these folks literally have to concern themselves with keeping a healthy supply of electricity for health and safety.

 

[Tym]

I am a new Lucid Air Pure owner with a used 2024 RWD with 20" wheels and a 394 stated EPA range.

why when my battery is charged to 100% does the miles remaining only say 370 miles, and not start with the EPA estimate of 394 miles?

The problem is the the EPA formula; it does not include the following:

• Driving behavior (speeding, hard braking, etc.)‍
• Weather conditions (extreme heat or cold)‍
• Elevation changes (hills and mountains reduce efficiency)‍
• Payload (passengers, cargo, roof racks)‍
• Charging habits (frequent fast charging or incomplete charges)

Your lucid is showing remaining mileage based on miles/kWh

 

[Aka-none]

Personally I would think something a bit more variable but possibly more accurate.
Take the current rate of consumption over time and compare against remaining power to come up with a range.

 

[Cosmo Cruz]

Who charges to 100% ?

Must be those folk who overfill their gasoline tanks and destroy the evaporation canister system = click, click, click click click ...

 

[borski]

Who charges to 100% ?

Must be those folk who overfill their gasoline tanks and destroy the evaporation canister system = click, click, click click click ...

I did today, for a long road trip where I didn’t want to stop to charge

 

[Aka-none]

I do for a long trip, daily 80%, trip 100% or as close as I can get. why? because I want all those electrons for myself. is it bad for the battery? sure if you charge to 100% and let it sit for days+
The folks in the cruisers forum spend a lot more time on power management and battery life than most of us ever will. if we loose power we get and walk, if they lose power it's a different story.

So yes I do charge to 100% for trips.

 

[mikecronis]

Big fan of the 70%-30% SOC range. Just ran testmycode.cc and I'm at 96% battery health after 3 years.