Trip Computer efficiency is wrong and here's my proof

[Solomente]

I have a 2025 Air Pure with 20 inch wheels. My lifetime efficiency after 4k miles was 4.11 m/kwh but lately it's been dropping and I've struggled for weeks to have any drive get past 3.7 m/kwh. I live in the Southeast and still have most days where the temp is in the 50s-70s, and since I have summer tires, I drive a backup ICE car when the temperature infrequently drops into the 30s, so I'm not getting a huge winter-weather efficiency crash that might happen with other drivers. I charge my car nightly in my garage (originally to 80%, but now to 75% since 2.8.7 broke regen in my car) , using a standard Level 1 (110v) outlet, and the Lucid charging cable. Here's what is happening...

If I get in my car and drive to work, I will get efficiency in the mid 3s, maybe 3.75 if I'm lucky. My drive is mostly 45mph roads.

If I open the Lucid app and wake up my car a few minutes before I leave, the car will signal that it's starting to charge and then anywhere from 10 seconds to a minute later it will finish charging, since it was basically full already.

IF I DO THAT SECOND STEP WHERE I WAKE THE CAR AND "CHARGE" RIGHT BEFORE LEAVING MY EFFICIENCY RATING IS ALWAYS WAY HIGHER.

I noticed this anecdotally for some time but now I've started to specifically test it. For the past two weeks I have not woken the car with the app and have never gotten into the 4's a single time on m/kwh. Yesterday I did the trick opening the Lucid app 5 minutes before I left my house and my efficiency rating after my whole day (approx 40 miles to/from work, plus going out to lunch) was 5.0 m/kwh. This morning I just did it again and came to work and got 5.2 m/kwh. Conditions are the same - it's been upper 50s to low 60s every morning this week and I haven't used the HVAC at all.

I'm fully prepared to hear that it's in my head , but I would urge you to try this. I drive the same way to work every day and am now at 5k miles. I know what my efficiency averages are, I know what the weather conditions are, I am extremely cognizant whether I'm running HVAC... the difference in efficiency is not explainable by any of those things. It is 100% caused by this weird trick.

Why? I don't know but my best guess is the car is mis-measuring the amount of kwh onboard after the brief top-up charge so it thinks you've used less energy than you actually have, thus showing a higher efficiency rating. To be clear, I am NOT stating that the car is actually more efficient. I am saying this little trick of opening the app confuses the car as to how many kwh or power it actually has, thus throwing the trip computer efficiency calculation off.

 

[Northpointe]

If I agonized over things such as this my ownership experience would be miserable. Clearly your car always has plenty of range to get you where you need to be as evidenced by your charging habits and low miles.

 

[Solomente]

If I agonized over things such as this my ownership experience would be miserable. Clearly your car always has plenty of range to get you where you need to be as evidenced by your charging habits and low miles.

Where did I say I was agonizing? I'm not complaining about it, I'm pointing out that the calculation is wrong. Tons of people post comparisons about that efficiency calculation all the time so it's pertinent to know whether it's accurate or not. It also is freeing to know I'm not crazy, and that there's a tangible explanation why my efficiency will go from 3.2 to 5.2 for the same drive in the same conditions. That's not a minor difference, BTW, it's like going from 25mpg to 40mpg.

 

[tjhappel]

I have a 2025 Air Pure with 20 inch wheels. My lifetime efficiency after 4k miles was 4.11 m/kwh but lately it's been dropping and I've struggled for weeks to have any drive get past 3.7 m/kwh. I live in the Southeast and still have most days where the temp is in the 50s-70s, and since I have summer tires, I drive a backup ICE car when the temperature infrequently drops into the 30s, so I'm not getting a huge winter-weather efficiency crash that might happen with other drivers. I charge my car nightly in my garage (originally to 80%, but now to 75% since 2.8.7 broke regen in my car) , using a standard Level 1 (110v) outlet, and the Lucid charging cable. Here's what is happening...

If I get in my car and drive to work, I will get efficiency in the mid 3s, maybe 3.75 if I'm lucky. My drive is mostly 45mph roads.

If I open the Lucid app and wake up my car a few minutes before I leave, the car will signal that it's starting to charge and then anywhere from 10 seconds to a minute later it will finish charging, since it was basically full already.

IF I DO THAT SECOND STEP WHERE I WAKE THE CAR AND "CHARGE" RIGHT BEFORE LEAVING MY EFFICIENCY RATING IS ALWAYS WAY HIGHER.

I noticed this anecdotally for some time but now I've started to specifically test it. For the past two weeks I have not woken the car with the app and have never gotten into the 4's a single time on m/kwh. Yesterday I did the trick opening the Lucid app 5 minutes before I left my house and my efficiency rating after my whole day (approx 40 miles to/from work, plus going out to lunch) was 5.0 m/kwh. This morning I just did it again and came to work and got 5.2 m/kwh. Conditions are the same - it's been upper 50s to low 60s every morning this week and I haven't used the HVAC at all.

I'm fully prepared to hear that it's in my head , but I would urge you to try this. I drive the same way to work every day and am now at 5k miles. I know what my efficiency averages are, I know what the weather conditions are, I am extremely cognizant whether I'm running HVAC... the difference in efficiency is not explainable by any of those things. It is 100% caused by this weird trick.

Why? I don't know but my best guess is the car is mis-measuring the amount of kwh onboard after the brief top-up charge so it thinks you've used less energy than you actually have, thus showing a higher efficiency rating. To be clear, I am NOT stating that the car is actually more efficient. I am saying this little trick of opening the app confuses the car as to how many kwh or power it actually has, thus throwing the trip computer efficiency calculation off.

Honestly best guess would be your waking the car’s systems on “shore” power and takes a considerable amount more energy then any of us know. Getting pack up to normal temps etc. Just a theory but I’d bet I’m close.

 

[Solomente]

Honestly best guess would be your waking the car’s systems on “shore” power and takes a considerable amount more energy then any of us know. Getting pack up to normal temps etc. Just a theory but I’d bet I’m close.

Thanks for weighing in. This is definitely something I thought of, but my experience tells me it's not what's happening for a few different reasons. First, my car is in a garage and doesn't need much battery conditioning. This morning it was 67 degrees in my garage when I got in the car to leave. Second, this behavior is the same whether I wake the car up 10 minutes or 1 minute before I leave my house. It's not enough time to precondition. Third, the app indicates charging started, then completed, within a very short window. On a 110v plug, I don't think the car can do much in that amount of time. For example, if I turn the heat on in the car via the app, the charge percentage actually goes down while it's plugged in because the HVAC uses more power than the 110V can deliver. I have to assume battery preconditioning is at least somewhat similar.

 

[tjhappel]

Thanks for weighing in. This is definitely something I thought of, but my experience tells me it's not what's happening for a few different reasons. First, my car is in a garage and doesn't need much battery conditioning. This morning it was 67 degrees in my garage when I got in the car to leave. Second, this behavior is the same whether I wake the car up 10 minutes or 1 minute before I leave my house. It's not enough time to precondition. Third, the app indicates charging started, then completed, within a very short window. On a 110v plug, I don't think the car can do much in that amount of time. For example, if I turn the heat on in the car via the app, the charge percentage actually goes down while it's plugged in because the HVAC uses more power than the 110V can deliver. I have to assume battery preconditioning is at least somewhat similar.

While I agree with all that you’re saying…. I too live in a climate that’s basically always between 61-73, I notice a difference if I take it off the charger “fresh” and when I take it off when it’s done charging in “sleep” mode. I guess another lucid mystery!! Enjoy the car, luckily we have a decent amount of range.

 

[Aka-none]

You do consider that
%-1 < % charged as displayed < %+1
I think what you see is the difference between displayed charge and actual based on however it decides to round the charge.
Lithium batteries are cool in that the output voltage barely changes as the battery discharges

 

[Solomente]

You do consider that
%-1 < % charged as displayed < %+1
I think what you see is the difference between displayed charge and actual based on however it decides to round the charge.
Lithium batteries are cool in that the output voltage barely changes as the battery discharges

I'm sorry you'll have to translate that for me as I don't understand what you're saying. I'm not talking about the displayed charge. I'm saying when I charge to 80% (or whatever limit I set) every day and drive the same route in the same conditions, the efficiency (miles per kilowatt hour) varies drastically based on one factor alone. And that factor is whether I use the phone app to wake up the car right before I leave the house.

 

[tarator]

Which efficiency numbers are you looking at? "Since last charge"? Reset one of the trips in the morning before you drive off and compare those instead.

 

[socktucker]

charge my car nightly in my garage (originally to 80%, but now to 75% since 2.8.7 broke regen in my car)

What does this mean?

 

[socktucker]

If I agonized over things such as this my ownership experience would be miserable.

Same, I have no idea what efficiency I get. It cant change enough for me to matter. But I don't even know how much money I have either so, I'm just kinda that way.

 

[Solomente]

Which efficiency numbers are you looking at? "Since last charge"? Reset one of the trips in the morning before you drive off and compare those instead.

Yes, "since last charge" but the lifetime efficiency goes up or down relative to what I'm seeing on the "since last charge" efficiency anyway. I'll reset one and replicate the test

 

[Solomente]

What does this mean?

After update 2.8.7, regen acts like I charged to 100% when I'm only at 80%, so I changed my nightly charging limit to 75% to get some of my regen back

 

[Takeshi]

IF I DO THAT SECOND STEP WHERE I WAKE THE CAR AND "CHARGE" RIGHT BEFORE LEAVING MY EFFICIENCY RATING IS ALWAYS WAY HIGHER.

You are allowing a charge on the car via waking it up from the app, and this is exactly what helps you achieve the better miles per kWh each morning.
The battery and car is warmed up now via the electricity energy from your outlet and is not counted towards your miles per kWh since last charge. This means you will not start off with a cold battery leading to the worse miles per kWh you see on your other documented efficiency numbers.
If you did not wake it up, it would retain the stats from when it was done charging previously along with however much energy in the pack it took to keep the pack in optimal battery operating conditions.

 

[Solomente]

You are allowing a charge on the car via waking it up from the app, and this is exactly what helps you achieve the better miles per kWh each morning.
The battery and car is warmed up now via the electricity energy from your outlet and is not counted towards your miles per kWh since last charge. This means you will not start off with a cold battery leading to the worse miles per kWh you see on your other documented efficiency numbers.
If you did not wake it up, it would retain the stats from when it was done charging previously along with however much energy in the pack it took to keep the pack in optimal battery operating conditions.

I understand that concept but it's not what's happening. I am on a 110v outlet, level 1 charging. This trick works if I wake the car 60 seconds before I leave. That outlet can't produce enough power in 60 seconds to heat the battery a single degree

 

[socktucker]

You are allowing a charge on the car via waking it up from the app, and this is exactly what helps you achieve the better miles per kWh each morning.
The battery and car is warmed up now via the electricity energy from your outlet and is not counted towards your miles per kWh since last charge. This means you will not start off with a cold battery leading to the worse miles per kWh you see on your other documented efficiency numbers.
If you did not wake it up, it would retain the stats from when it was done charging previously along with however much energy in the pack it took to keep the pack in optimal battery operating conditions.

This makes perfect sense.

 

[Solomente]

This makes perfect sense.

In a bubble, yes it does. But it doesn't apply to my scenario, so my initial hypothesis holds. I am only waking up my car sometimes a minute or two before I leave. A cell phone can't even get 1% charge in that time, so my car on a 110v plug is not preconditioning in 2 minutes.

 

[socktucker]

I understand that concept but it's not what's happening. I am on a 110v outlet, level 1 charging. This trick works if I wake the car 60 seconds before I leave. That outlet can't produce enough power in 60 seconds to heat the battery a single degree

And now I’m lost again.

 

[jedwin]

My understanding is that the “since last charge” line/calculation includes kilowatt hours that are lost while you are parked – headlights staying on before it gets locked or goes to sleep, any HVAC that may be left on again until it goes to sleep, etc. Plus whatever energy it takes waking up. All this is not much necessarily, but it’s likely to give you slightly or notably lower efficiency numbers, especially on short drives (40 miles counts as short).

So when you do a quick top off charge, even one that adds next to nothing, it resets that, and the “since last charge” is a more accurate measurement of the energy used on the subsequent drive

Conversely, other threads here have left the impression that the trip A or trip B lines really do only count energy used while driving. (including energy used on HVAC while driving).

So for your testing, it might be interesting to try one of your morning drives with one of the Trip lines freshly reset, and compare that to both the “since last charge“ line when you do top off just before leaving, and another day when you don’t…

 

[Solomente]

My understanding is that the “since last charge” line/calculation includes kilowatt hours that are lost while you are parked – headlights staying on before it gets locked or goes to sleep, any HVAC that may be left on again until it goes to sleep, etc. Plus whatever energy it takes waking up. All this is not much necessarily, but it’s likely to give you slightly or notably lower efficiency numbers, especially on short drives (40 miles counts as short).

So when you do a quick top off charge, even one that adds next to nothing, it resets that, and the “since last charge” is a more accurate measurement of the energy used on the subsequent drive

Conversely, other threads here have left the impression that the trip A or trip B lines really do only count energy used while driving. (including energy used on HVAC while driving).

So for your testing, it might be interesting to try one of your morning drives with one of the Trip lines freshly reset, and compare that to both the “since last charge“ line when you do top off just before leaving, and another day when you don’t…

That's really great feedback, thank you! It does make sense to me that it's about when the data is reset versus how much power my 60 second charge is adding. I will reset Trip A and test this again a few times.