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

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bfab

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I am a new Lucid Air Pure owner with a used 2024 RWD with 20" wheels and a 394 stated EPA range. I understand that Lucid - unlike my old friend, my Chevy Bolt - just uses the EPA range-based efficiency to estimate miles remaining, and that I need to do a calculation with battery SoC and trip efficiency to get real-life range.

However, if this is true, then 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?
 
Dunno, it does in my 2025 AT w/20" wheels.
 
bfab said:
...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?
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Because your car's battery no longer holds as much energy as it could when the car was brand new. This happens with all EVs.
It now has about 370/394 = 94% of its original capacity. Capacity loss is faster in the first year or two, and slows down after that. Most EVs show about 90% of original capacity remaining at the 10-year mark.
 
But my understanding is that the "miles remaining calculation" is ignorant of not only driving technique, but also temperature and aging / lifetime that may also impact battery capacity. So I'm not sure I buy that the car "knows" the battery is a year old when it makes this calculation.

Also a decrease of 6% in battery capacity in one year sounds like an awful lot if this is true.
 
bfab said:
But my understanding is that the "miles remaining calculation" is ignorant of not only driving technique, but also temperature and aging / lifetime that may also impact battery capacity. So I'm not sure I buy that the car "knows" the battery is a year old when it makes this calculation.

Also a decrease of 6% in battery capacity in one year sounds like an awful lot if this is true.
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I'm far from an expert from from what I've heard, the worst of battery degredation tends to happen in the first year. After that the degredation slows down.
 
bfab said:
But my understanding is that the "miles remaining calculation" is ignorant of not only driving technique, but also temperature and aging / lifetime that may also impact battery capacity. ... Also a decrease of 6% in battery capacity in one year sounds like an awful lot if this is true.
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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.

www.geotab.com

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 www.geotab.com
 
Also verify your tires are set to the correct ones in the system? I assume it's using the tire setting to display the EPA number at 100%.
 
illopp00 said:
Also verify your tires are set to the correct ones in the system? I assume it's using the tire setting to display the EPA number at 100%.
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Yes, I did do that, and they are correct, but thanks for the good reminder
 
j4gates said:
Google "how to recalibrate EV battery"
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Thanks, this is very interesting, and I will try it. I might try talking to Lucid 1st - do you know if this is officially recommended by them?
 
I have a 2022 Touring with a rated 425, when fully charged it was 433 in the beginning and then started dropping around the 4th month or sometimes either after an update. I'm now down to 405 (404 after yesterday) at 100% which is a 6.47% loss after 3 years. Your car may be on the same track. I did ask for a battery check and was told it was in the +90% range still. You'd probably need to ask the original owner what they were originally seeing at fully charged and then work backwards to see if you're loose is with in reason.
 
tarator said:
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.
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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.
 
j4gates said:
Google "how to recalibrate EV battery"
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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 have to think ambient temperature, HVAC settings, and related has some effect on calculation of estimated range (which is all the number is).
 
doubletwist said:
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.
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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.
 
tarator said:
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.
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I kinda agree.
I don't think it's a matter of mathematical proficiency. More of a preference.

It's not so much about a calculation as it is more reliable data from which to make a decision (charge or not).

Those remaining miles are dynamic, based on various factors (speed, elevation, temp, etc ). Therefore, for me, they're not as reliable. The battery energy percentage minimizes the guessing. Early iny ownership, I even tried using the miles remaining. Then I saw the percentage; less than what I was thinking. I switched to percentage.

I like that the native nav app shows you the miles or percentage remaining at a travel destination. I prefer the percentage. Especially if I'm unsure how far to the next charger.
 
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