Actual charging time almost 2X longer vs predicted.

[krissrock]

it's really kinda impossible for the car to make an accurate estimate. things change...the temp of the batter for example... as you get more charge, its slower overall... Going to 85% was probably the biggest factor

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[Petzi]

I had my first charging session in the wild yesterday on the free EA network. I plugged into a 350kw charger with 25% and target of 90% trying to burn up as much of my 30 free minutes as I could. It was in the wee hours of the morning so so one was waiting on the chargers for me to squeeze out those last few drops. The charge started at 195kw and dropped to 70.6kw by the time my 30 minutes was up and only made it to 87%. Since the charge started at "only" 195kw from the 350kw capable charger, is it of much benefit to seek out the 350kw charger vs a more common 150kw? If it is more about the car's ability to take a charge than the charger's ability to give it, is there a benefit to chasing the higher powered chargers?

macan is capable to charge from 10% - 80% in 21 minutes as often tested. you charged from 25% - 87% in 30 minutes. as the same tests show, the speed is not the same over the whole time it starts quite slow reaches a peak and gets slower to the ende, very slow above 80%.

 

[Was87911]

macan is capable to charge from 10% - 80% in 21 minutes as often tested. you charged from 25% - 87% in 30 minutes. as the same tests show, the speed is not the same over the whole time it starts quite slow reaches a peak and gets slower to the ende, very slow above 80%.

All true. My question/curiosity which I can solve myself in a couple of weeks is if the search for a higher kw charger is worthwhile given the 350kw charger I used gave (or the car only accepted) only 195kw to start. The charge had dropped to 126kw by minute 15 of the session so I might have been in the range of a 150kw charger within 10 minutes if a 150kw charger would really give me 150kw. I slept through the question when I charged it at home but maybe I'll bring graph paper with me on the next go.

 

[seabird]

All true. My question/curiosity which I can solve myself in a couple of weeks is if the search for a higher kw charger is worthwhile given the 350kw charger I used gave (or the car only accepted) only 195kw to start.

Any additional amount of time spent driving to find a 350kW charger would probably be better spent charging at the 150kW station.

Yes, the 350kW stations are faster when they're working fully--I've seen as high as 262kW in my Macan and charged up 75kW in 20 minutes. But a 150kW station is still going to get you 75kW in a 30 minute session. It might be "50% longer" but it's a single digit number of minutes and not a daily occurrence. It's when the 150 is de-rated to 50-60kW that I get annoyed.

Personally, I'm just going to the one that is nearest my route and has an empty bay. If it's 350kW, then great. But I'm not skipping a 150 to find a 350.

 

[Petzi]

All true. My question/curiosity which I can solve myself in a couple of weeks is if the search for a higher kw charger is worthwhile given the 350kw charger I used gave (or the car only accepted) only 195kw to start. The charge had dropped to 126kw by minute 15 of the session so I might have been in the range of a 150kw charger within 10 minutes if a 150kw charger would really give me 150kw. I slept through the question when I charged it at home but maybe I'll bring graph paper with me on the next go.

it is a well tested fact and my own experience that the macan can charge at a good fast charger a bit more than 270kwh. that is peak which can be reached between 10-50/60%. Average speed when charging 10-80%. is 150 kwh. conclusion: charging at a fast charger speeds the charging up by 5-10 min. charging at a fast charger speeds up significantly when charging 10-50%.

 

[sor]

This can be because your battery isn’t warm enough, or too warm.

It can be because the charger itself is throttling due to its own factors - the cabling is liquid cooled and has its own limits. A 350kw charger is not always primed and reliably going to provide 350kw. Ideally it would if it is in good repair.

It can be because your battery isn’t empty enough to take the higher speeds.

 

[ColdCase]

Mine seems to consider a number of factors like SOC, battery temp, charger capability when estimating time. It seems to initially under estimate the time it takes from 80-90% and revises it as it approaches 80%, however. I think sometimes the charger doesn't meet its commitment, unexpected and hard to predict.

 

[sor]

it's interesting to note the original posting was about the "Macan's on screen predicted" charge time being 2x "wrong" - not how long the actual charging took…

the actual charge time was inline with expectations and appropriate performance given conditions - the charge session took "2x" minutes - but right after plugging in the Macan's estimated charge time to reach the target SOC was 10 minutes…

that original 10 minute estimate proved to be over 2X wrong!!

so I believe the feedback was "why is the car predicting" 10 minutes when it should know that's not going to happen - Porsche engineers and their software should know from 30-80% is NOT linear and you shouldn't promise 10 minutes when you know getting to 80% takes 22 minutes…

it does seem laughable that Porsche does not know their segmented taper curve charge rate maximum's to adjust their estimate to be more accurate…

so why did the car estimate 10 minutes to complete a charging session that was never expected too be complete in 10 minutes by Porsche's _OWN_ standards.

I thought the OP showed 15 minutes. 15 minutes from 37% to 85% seems totally reasonable estimate for this car which Porsche claims can go from 10% to 80% in 21 minutes.

That’s why it seems like the station was underperforming in this case, which is also fairly common. The car was continuously optimistic because it was estimating on the assumption the charger would kick up to what it is supposed to deliver.

 

[Petzi]

I thought the OP showed 15 minutes. 15 minutes from 37% to 85% seems totally reasonable estimate for this car which Porsche claims can go from 10% to 80% in 21 minutes.

That’s why it seems like the station was underperforming in this case, which is also fairly common. The car was continuously optimistic because it was estimating on the assumption the charger would kick up to what it is supposed to deliver.

perfect explanation @sor .

 

[ChrisFromUK]

It would be very useful if Porsche would display the charge rate requested alongside the actual charge being supplied. Then we could easily see situations where the charger isn't able to supply what the car is asking for and so the charging session will be longer.

 

[Petzi]

It would be very useful if Porsche would display the charge rate requested alongside the actual charge being supplied. Then we could easily see situations where the charger isn't able to supply what the car is asking for and so the charging session will be longer.

the car “requests” the optimal charge rate which depends on the charging status of the battery. its a misconception that the car “decides” to take less charging than possible. actually a lot of chargers fail to provide the requested charging rate. how could the car “predict” this ?

 

[ChrisFromUK]

how could the car “predict” this ?

I can't predict it but it would be useful to be able to show that the car isn't able to charge as fast as it would like to due to the charger not being up to the job.

 

[Petzi]

car meets charger, says “hi i am an macan, i can
charge with up to 270kwh” charger says: “hi, nice to meet you, i can charge up to 350 kwh”.car thinks: “thats fine, we will be on our way in 20 min”.
tragedy: charger did lie. owner blames the car…

 

[SteveInKirkland]

I bet if 50 of us provided charge curves for a few weeks, I could build a parameterized model which more accurately predicted an actual charge time. I wonder how close it would be to just using my observed charge curves as the data to learn the function.

 

[seabird]

that original 10 minute estimate proved to be over 2X wrong!!

The charging station delivered less than 50% of the requested power...taking a 15 minute estimate to 28 minutes, which was correctly calculated within a minute of the charge starting. This is not "over 2X wrong".

so I believe the feedback was "why is the car predicting" 10 minutes when it should know that's not going to happen - Porsche engineers and their software should know from 30-80% is NOT linear and you shouldn't promise 10 minutes

It was showing 15 minutes from 37 to 80%, which is the correct estimate if the 350kW station was operating normally.

so why did the car estimate 10 minutes to complete a charging session that was never expected too be complete in 10 minutes by Porsche's _OWN_ standards.

...it didn't.

I bet if 50 of us provided charge curves for a few weeks, I could build a parameterized model which more accurately predicted an actual charge time. I wonder how close it would be to just using my observed charge curves as the data to learn the function.

No need: https://evkx.net/models/porsche/macan/macan_4/chargingcurve/

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