Extremely Slow Charging Speed at EA

[sor]

I would still let it sit at low SoC for a few hours because this fixed slow DC charging for me, after it being a garage queen for a few weeks seemed to cause this. The dealership will probably just start with the recalibration anyway.

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[Paris92]

I would still let it sit at low SoC for a few hours because this fixed slow DC charging for me, after it being a garage queen for a few weeks seemed to cause this. The dealership will probably just start with the recalibration anyway.

Mine definitely sits in the garage for weeks at a time.

 

[sor]

Spent a few weeks just doing maybe one or two short trips a week. After I experienced slow dc charging, I let it sit for a few hours at ~25% and SoC jumped to 40% (rebalance made more cells available). Then I charged it at home to 85% and a few hours later it went to 75% (more space to charge). After that fast charging was back to normal.

I realize the official rebalance procedure is more extreme than what I observed but this was enough for me to cancel my appointment.

I would still choose it over any other EV on the market today.

 

[Paris92]

Spent a few weeks just doing maybe one or two short trips a week. After I experienced slow dc charging, I let it sit for a few hours at ~25% and SoC jumped to 40% (rebalance made more cells available). Then I charged it at home to 85% and a few hours later it went to 75% (more space to charge). After that fast charging was back to normal.

I realize the official rebalance procedure is more extreme than what I observed but this was enough for me to cancel my appointment.

I would still choose it over any other EV on the market today.

Thanks for the advice. Will try it out.
And your avatar... nice LM, and latte art. I use an ECM Synchronika.

 

[rcomeau]

Spent a few weeks just doing maybe one or two short trips a week. After I experienced slow dc charging, I let it sit for a few hours at ~25% and SoC jumped to 40% (rebalance made more cells available). Then I charged it at home to 85% and a few hours later it went to 75% (more space to charge). After that fast charging was back to normal.

I realize the official rebalance procedure is more extreme than what I observed but this was enough for me to cancel my appointment.

I would still choose it over any other EV on the market today.

Does anyone have an idea of what goes on during re-balancing? One might expect a % or so in changes, not 15%. Cells are not tuned off and on individually. Re-balancing tries to get all cells to the same state of charge so they can charge and discharge in a similar way as a group so they all provide the same voltage as they discharge and all charge equally when exposed to the charging voltage.

 

[SergeyIndy]

100% Macan problem. You did everything right as we asked, you ran it down low with 22% low enough, then you can clearly see your battery temp is in ideal range (right bracket of the left tube temp indicator is inside that bracket), so you should be getting speeds well over 200kW. Something is wrong with the onboard DC charger or the Battery itself -- no question, but strangely no errors.

Then the range is way down for the temps you are in, as you are basically at 180 miles, that is crazy low, as if half of your battery is basically dead.

Home AC charging is as expected, so all good there.

Please keep us posted on the findings and resolution!

 

[SergeyIndy]

Does anyone have an idea of what goes on during re-balancing? One might expect a % or so in changes, not 15%. Cells are not tuned off and on individually. Re-balancing tries to get all cells to the same state of charge so they can charge and discharge in a similar way as a group so they all provide the same voltage as they discharge and all charge equally when exposed to the charging voltage.

We have the data about it on the Taycan forum. We see anywhere between 1%-3% what I call temporary increase in the reported SoH. This is due to the fact that the battery cells get I call it chemically rinsed as they go low and stay there and then go high and stay there. This allows exactly as you say to align them on SoC, Temp, and Voltage. The main benefit is that the rebalance is the only way for the bad cells to come forward and the way we detect them is via Cell graphs in the CarScanner as you look for outliers. You only need 1 cell to go bad in the Taycan for it to be dead with what we call Red Circle of Death.

 

[sor]

Does anyone have an idea of what goes on during re-balancing? One might expect a % or so in changes, not 15%. Cells are not tuned off and on individually. Re-balancing tries to get all cells to the same state of charge so they can charge and discharge in a similar way as a group so they all provide the same voltage as they discharge and all charge equally when exposed to the charging voltage.

My uninformed idea of this (for all EVs not just Macan) is that if you have some cells with maybe 50% SoC and some cells with zero, your overall SoC is zero because it needs to be able to pull energy from multiple cells to have enough power to operate. When it sits in this state and there’s actually room to rebalance it can transfer energy from cells with energy to empty cells, which actually restores SoC since none are at zero and it can now draw energy in parallel again.

similarly on the top end I think there are artificial limitations to how it can charge if some cells in a bank are full and others are not, it cannot necessarily top off all cells and has to stop charging when some are full.

It also limits your charging speed because it can only put energy into some cells and not others.

I suspect the 800v architecture and split pack (capable of 400v charging) makes this a bit more complicated and difficult for a BMS to keep things balanced. Especially with minor draws like short trips or sitting idle that might not demand energy from every cell.

 

[chrisk]

Todays update.

Decided to put some miles on the car to drain the battery. Lunchtime trip from San Francsico to Cupertino for lunch with a friend, then back.

Arrival in Cupertino:

.

After lunch I set the Porsche Trip Planner to head to the EA Flagship in SF as a first stop, then home:
(note also "only" 86-mile range at 50% charge on a bright sunny mid-70-degree day)

Arrival at EA SF: Battery at 90-degrees. Battery SOC at 22%. Ideal for fast charging, or no?

There were only seven (7) cars in the 22-bay facility while I was charging.

Charging Speed at EA: Charged for five minutes. Speed never increased past 37kW.

There is an EVgo location two blocks away from this EA location, so I went over there to try charging.

First Charger at EVgo: Charged at 35-36kW.

Only charged at 35kW or lower, so I tried a second charger at EVGo:

This one only charged at 35kW or lower.

On my way home I stopped at the Porsche Dealership and scheduled an appointment to have it looked at on March 5th.

Charging on the home charger afterwards:

Charge your car to 95%. Then unplug and leave undisturbed for 10 hours to balance the battery.
I bet this will solve your problem. I had exactly the same issue as you 3 times and this resolved it.

 

[craz8]

As I'm doing a BMS reset cycle at the moment, here's my discharge data. I missed 60 miles as I was driving, but the rest of the data is all from the last 3 weeks.

Notice how high my Miles/1% gets - yay, 450 miles of range at 100% in this thing! And then when I got it down to 4% today with 2 miles of range, giving me a 100% range of 50 miles

SOC %	Displayed Range in Miles	Miles Per 1%	Miles of Range at 100%
80	359	4.5	449
70	269	3.8	384
60
50	170	3.4	340
40	119	3.0	298
30	81	2.7	270
20	40	2.0	200
10	15	1.5	150
4	2	0.5	50

I think a common theme is that people who drive little, or many short trips, hit a bug in the software where the car loses track of charge, and the BMS overnight balancing never gets it back.

I have so many 6 mile trips in my system, but these are mostly actually a pair of 3 mile trips, close enough together to be recorded as one. Last week I drove a trip of over 50 miles for the first time in many months, and the BMS dropped 5% extra SOC overnight down to 40% in the table above where the 100% range actually dropped to a value that matches my miles/kwh rate.

Tomorrow, I charge to 95%, and will document that. (I'm worried about 100%, as all my recent charge sessions have all rebalanced to a higher SOC after the session). Internet lore suggest limiting to 32amps/7.6kw too, which I have time for, so why not (this might have been a limit of the hardware used by the reporter of their reset).

The last DC charge I did was a month ago at 80kw at the dealer for about 10% of charge after the software update. Before that might have been November at EA? So I can't tell if I had any slow charging limits with that process since that time.

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