weird % battery used during long drive

[ckyr]

Hi.
I have a 2023 Taycan GTS, never any issues with charging, battery etc.
I am attaching a photo of the trip computer after yesterday's drive: drove about 134 miles and car says it consumed 40.8kWh/100mi (it was less than -10C the entire drive and car was pretty loaded). If this consumption number is accurate, car should have consumed about 55kWh, or about 65% of the usable capacity of the HV battery (about 84kWh if I am not mistaken). However, the car from 80% down to 5%, with only 9 miles of range left.
Any idea for the cause of this significant discrepancy between the two numbers? I almost ran out of range yesterday...
Thanks.

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[Jasper4S]

IMO opinion, three factors, and nothing to worry about:

- Average speed indicates you took the highway. Higher speed higher consumption
- Weather, cold, thus less efficient and energy is used to warm up your vehicle instead of driving
- Weight, thus less efficient

the range indicator is a estimated range, since this trip is probably not a normal one for your vehicle the calculation/indication is a (in your eyes) weird guess.

 

[ckyr]

Thanks Jasper.
I am not worried about the increased consumption, I agree with you, temperature and weight aren’t your friends…
My concern is the discrepancy between the % battery loss (75%) and calculated battery capacity consumption (close to 65%). Shouldn’t these numbers match? And yes, range is an estimate, but kWh should be able to be measured accurately.

 

[Jasper4S]

That is weird indeed. The numbers are not adding up. My take is Porsche is really bad at math ?

5% battery and 9 miles range means you get 180 on a full battery. You did 133 on 75% battery, which adds up. So that explains the range calculation.

The consumption is weird, maybe somebody here knows if the shown consumption is the consumption used for driving, so no energy used for ac/heater and loss of energy? If so, that number tells us drivers nothing and is useless

 

[SpaceMaster]

Every couple of weeks I do a drive which is exactly 182km long on roads that don’t allow for much variation in driving style. I use this trip to gauge different setups and external conditions and their effect on consumption. Since 2022 all these trips have been extremely consistent differing by no more than a % between previous drives on the same tyres and outside temperature.

I also do the same calculation that you did and no matter the consumption, it always added up to every 1% battery be around 0.85KWh. -/+ 0.02KWh

After getting the battery diagnostic software recall and check, which it passed, I’ve done this trip twice and in both cases I’ve experienced the same consumption as before but higher drop in percentage of the battery, as you did. Doing the same calculation it now comes up to 1% of battery used to be 0.64KWh. As if my battery has degraded 25% overnight. The SOH says 94.3% so I strongly suspect that with the new diagnostic software in the BMS, Porsche has decreased the usable capacity of the battery until they find a proper fix with the data collected from ARB7.

 

[Gru]

the discrepancy between the % battery loss (75%) and calculated battery capacity consumption (close to 65%). Shouldn’t these numbers match?

in my experience.... no.

I attach below a screenshot of a long highway trip. Porsche app reports 28.5 / 33.2 / 26.7 kWh / 100km for 3 legs of the trip, while Car scanner gave me 31.8 / 37.6 / 29.6 . So about 3kWh more than Porsche. Heater wasn't working much, battery was already at more than 30°

Some can't handle money, Porsche can't handle numbers...

 

[chun]

Every couple of weeks I do a drive which is exactly 182km long on roads that don’t allow for much variation in driving style. I use this trip to gauge different setups and external conditions and their effect on consumption. Since 2022 all these trips have been extremely consistent differing by no more than a % between previous drives on the same tyres and outside temperature.

I also do the same calculation that you did and no matter the consumption, it always added up to every 1% battery be around 0.85KWh. -/+ 0.02KWh

After getting the battery diagnostic software recall and check, which it passed, I’ve done this trip twice and in both cases I’ve experienced the same consumption as before but higher drop in percentage of the battery, as you did. Doing the same calculation it now comes up to 1% of battery used to be 0.64KWh. As if my battery has degraded 25% overnight. The SOH says 94.3% so I strongly suspect that with the new diagnostic software in the BMS, Porsche has decreased the usable capacity of the battery until they find a proper fix with the data collected from ARB7.

If this is true, and it can be proven, Porsche will have a massive lawsuit happening. Any lawyer would take this class action lawsuit. Intentionally downgrading the quality of an already sold product and not disclosing it is highly illegal.

 

[Sace]

Are we sure that the energy used for heating is included in that number? Mine have always been off when looking at trips in the app and I have attributed that to not including auxiliary consumption in the numbers.

 

[ckyr]

Every couple of weeks I do a drive which is exactly 182km long on roads that don’t allow for much variation in driving style. I use this trip to gauge different setups and external conditions and their effect on consumption. Since 2022 all these trips have been extremely consistent differing by no more than a % between previous drives on the same tyres and outside temperature.

I also do the same calculation that you did and no matter the consumption, it always added up to every 1% battery be around 0.85KWh. -/+ 0.02KWh

After getting the battery diagnostic software recall and check, which it passed, I’ve done this trip twice and in both cases I’ve experienced the same consumption as before but higher drop in percentage of the battery, as you did. Doing the same calculation it now comes up to 1% of battery used to be 0.64KWh. As if my battery has degraded 25% overnight. The SOH says 94.3% so I strongly suspect that with the new diagnostic software in the BMS, Porsche has decreased the usable capacity of the battery until they find a proper fix with the data collected from ARB7.

Interesting. I am doing exactly the same. I drive the same 130 mile distance every week back and forth between November and March and occasionally the rest of the year and keep a log with the computer trip consumption and % battery loss to see the effect of temperature, summer vs winter tires etc. The numbers have been very consistent; what I calculate is within a couple of % from what the car shows as % battery drop during the drive.

The drive I am describing in my first post is the first with the huge discrepancy, 10% difference between the numbers, but also the first drive after the ARB7 recall, and the first in such cold weather.

I will be driving back the same distance in a couple of days and then again back and forth next weekend, so will report back if this is still an issue after the ARB7, or a one-off because of the weather.

@SpaceMaster , if you don't mind, please provide your updates as well.

 

[Gru]

Are we sure that the energy used for heating is included in that number? Mine have always been off when looking at trips in the app and I have attributed that to not including auxiliary consumption in the numbers.

I checked in another trip (early Nov.) where heater was constantly off (and no air co either):
28.8 (Porsche) vs 32.5 (Car scanner)

 

[ckyr]

I checked in another trip (early Nov.) where heater was constantly off (and no air co either):
28.8 (Porsche) vs 32.5 (Car scanner)

Which car scanner are you using?

 

[Gru]

that one, with an OBD2:
https://www.carscanner.info/

 

[McgR]

Did you precondition the car before departure without being plugged in? That could be a reason to use more energy than predicted. And maybe some longer down hill stretches with negative consumption.

For me the predicted range was always very accurate. I think the kwh/100 miles is a calculation. Like the total kWh /100 decreases gradually to numbers that are not correct either.

 

[SpaceMaster]

@SpaceMaster , if you don't mind, please provide your updates as well.

I will do this route tomorrow evening and report back.

Tonight I will charge to 100% this time to see if that will help the BMS get its bearings and see what I get for C*D/BP=NBC

C = Consumption (KWh/100km)
D = Distance (km)
BP = Battery Percentage used
NBC = Nett Battery Capacity (KWh)

 

[SergeyIndy]

I think you are overestimating usable battery capacity. I am at 14k miles and I lost 12% of SoH but leveled up to about 10% overall loss after rebalance. This means that my usable battery capacity is about 78kWh. I think this is may be your 10% you are not accounting for. Looking at your trip dynamic, I see nothing unusual in the overall range achieved. I had a similar experience on a recent 200 mile stretch with warmer temps, but rain, and 80 mph highway speed, and just myself in the car.

I recommend you reference the Baseline thread, get the OBD reader with the CarScanner app to get a read on your actual usable battery capacity, then cross reference car consumption numbers.

You can reference my post below on how to read and checksum your net usable capacity considering SoH degradation.

https://www.taycanforum.com/forum/t...ation-data-by-taycan-owners.12815/post-350013

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