Level 2 charging rate with a 50 amp capacity

[tonykara]

I installed the latest software update yesterday. Here is what I got just afterwards:

What were you getting before the s/w update? What did the update specifically address?

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[daveo4EV]

This is the info I've been looking for. I don't have enough history with my car, but reading here that NA cars do 11kW and my '22 is down at 9kW has been bugging the crap out of me for the few months that I've owned the car. Your post confirms something has changed (before I got the car), and no one really knows why it changed. Damn.

Porsche "knows" what changed - so far they have refused to disclose:

1. that this is being done
2. the reasons it needs to be done

it's a "silent" downgrade…

one can reasonably speculate as to their motivations to do this - but it's much much much more difficult to get them to admit they are doing this and why they are doing it.

 

[RAHRCR]

What were you getting before the s/w update? What did the update specifically address?

Mostly 10.3 or 10.4. No idea on the SW update.

 

[daveo4EV]

this now closed thread documents another case of a Porsche software update nerf'ing a 2024 Taycan

prior the update car charged at 11 kW just fine
after the update max charger rate is 9.6 kW

as to why/how Porsche targeted this VIN that's undisclosed…

https://www.taycanforum.com/forum/threads/i’ve-been-nerfed-slower-charging-after-ota-software-update.34083/

posts # 5 & 6 show charging session from the EVSE point of view prior to the update and after the update - the Taycan is clearly requesting less power from the EVSE after the update…the EVSE is simply too dumb to make this change on it's own - it's the car/OBC/Porsche-software that's changed.

thread was closed because it has no new contributions to this topic, but is a solid "me too" piece of data…

 

[RED!]

this now closed thread documents another case of a Porsche software update nerf'ing a 2024 Taycan

prior the update car charged at 11 kW just fine
after the update max charger rate is 9.6 kW

as to why/how Porsche targeted this VIN that's undisclosed…

https://www.taycanforum.com/forum/threads/i’ve-been-nerfed-slower-charging-after-ota-software-update.34083/

posts # 5 & 6 show charging session from the EVSE point of view prior to the update and after the update - the Taycan is clearly requesting less power from the EVSE after the update…the EVSE is simply too dumb to make this change on it's own - it's the car/OBC/Porsche-software that's changed.

thread was closed because it has no new contributions to this topic, but is a solid "me too" piece of data…

Yeah, that was me f-ing too...

 

[daveo4EV]

Yeah, that was me f-ing too...

yeah Porsche seems to want to downgrade all the North American Taycan's to 9.6 kW max charge rate - no disclosure as to why…

 

[RED!]

is someone able to calculate the average time lost for charging?
I understand it's not a simple linear equation since the battery charge varies at the bottom and top of charge - Its clear that I wasted a few thousand dollars installing two 60A circuits and chargers when 50A plug-a-cheapies (and the one that came with the car) would have been ARE all I can now use

 

[daveo4EV]

is someone able to calculate the average time lost for charging?
I understand it's not a simple linear equation since the battery charge varies at the bottom and top of charge - Its clear that I wasted a few thousand dollars installing two 60A circuits and chargers when 50A plug-a-cheapies (and the one that came with the car) would have been ARE all I can now use

it's a 20% loss in charging speed - for all practical considerations 240V 48/40 amp AC charging _IS_ linear - 11 kW vs. 9.6 kW doesn't really taper off until greater than 98/99% battery SOC - only above 98/99% do we start to see maximum charge rates that are less than 9.6 kW - and at that point in time you have less than 1% of battery capacity remaining which is less than 0.8 kWh or less than 843 watt-hours…the battery can run flat out linear at 11 kW (hell even 22/19.2 kW) from 0% to 98/98%. before needing to taper off…

it's very simple

take a daily distance of 60 miles driven
@ 3 miles/kWh that's 20 kWh's of battery that needs replenishing
10% charging loss overhead is there 22 kWh that needs to be restored to the battery

22 kWh / 11.52 kW = 114 minutes of expected charging time back to 80%
22 kWh / 9.6 kW = 137 minutes of expected charging time back to 80%

difference in charging time is 137 minutes - 114 minutes or 23 minutes longer

a 10% to 95% charging session for a Taycan is 85% battery - 85% of 83.4 kWh is 70.89 kWh - let's call it 71 kWh

71 kWh * 1.1 =78.1 kWh

so we need 78 kWh to charge a Taycan from 10% to 95%

78 kWh / 11.52 kWh = 406 minutes
78 kWh / 9.6 kWh = 487 minutes

487 minutes - 406 minutes =81 minutes longer to charge at 9.6 kW

* - I would estimate these calculations are accurate +/- 3% in terms of estimated actual charging times - also the times are based on "ideal" voltage - normal grid voltage varies from about 216 volts to 250 volts - so grid voltage higher or lower than the ideal numbers used in these calculations will cause a difference in charge time

** - during charging some power may be used by the vehicle in tasks other than charging the battery - this is in addition to the 10% factored overhead - that usage by the vehicle during a charging session may elongate a charging session due to increased power usage by the vehicle - only Porsche engineering could provide a more accurate estimate because only they know the policies during charging that may come to play and cause additional consumption during charging session…YMMV

any charging session that doesn't charge to 100% SOC is 20% slow at 40 amps vs. 48 amps…the taper curve plays no role in charge rates this slow…

it's a 20% loss in charging speed - 48 amps vs. 40 amps…

I'll stand by my estimates as being close enough as to not matter and highly accurate in a vast majority of cases.

 

[Briguy]

here is what i have filed as part of a complaint against Porsche on this issue.

 

[MaxPlastix]

I feel like this is confusing to discuss as "kW" because that depends too much on the voltage at the EVSE, and it seems Porsche doesn't scale charging to the voltage.

I have an 11kW charger ("9.6kW" AC/DC OBC) but it seems what they actually did is cut the current the car would request from the EVSE.

Most commercial L2 chargers in the US are from 3-phase, 208v, so where I used to be able to charge at 48A, I'm now getting less current (40A?). This means I don't get ~9.8kW any more, but closer to 8.3kW from the same car and EVSE.

That is so very not-cool to shove into a software update.

 

[MaxPlastix]

My car charges consistently at 10.3 or 10.4 Kw....

If you have a J1.1, I'd be curious to know what you find after today's OTA update.

 

[daveo4EV]

I feel like this is confusing to discuss as "kW" because that depends too much on the voltage at the EVSE, and it seems Porsche doesn't scale charging to the voltage.

I have an 11kW charger ("9.6kW" AC/DC OBC) but it seems what they actually did is cut the current the car would request from the EVSE.

Most commercial L2 chargers in the US are from 3-phase, 208v, so where I used to be able to charge at 48A, I'm now getting less current (40A?). This means I don't get ~9.8kW any more, but closer to 8.3kW from the same car and EVSE.

That is so very not-cool to shove into a software update.

I think you're making this too complex and confusing some things…

208V in North America is not 3 phase coming out out the EVSe - there are not enough physcial -electrical pins in the J-1772 connector to delivery 3-phase AC power…it only has two high voltage pins/connectors L1/L2 and in the case of 120V L1/L2(neutral) - 3 phase power would have L1/L2/L3 electrical connections in the J-1772 connector - and J-1772 connector lacks any L3 connector in the connector's physical design.

while the EVSE may be powered by 3-phase it only delivers single phase to the vehicle since that is all that is physically allowed by the J-1772 connector (NACS also)…

but mostly 3 phase power is NOT a thing in North America for EV charging - since there no accommodations for 3 phase power in the SAE EV charging specifications.

there are two limits at play

1. the limit of the Onboard charger (OBC) - which is either 11 kw or 9.6 kW depending on when/where/how you're meassuring it and what version of Porsche software your vehicle has installed…
2. the limit of power offered by the EVSE itself.

11 kw requires 240V @ 48 amps - 60 amp breaker
9.6 kw requires 240V @ 40 amps - 50 amp breaker

Porsched vehicle charging software has _NEVER_ reported the raw power delivered by the EVSE inside the vehicle - it's alwasy been the effective charge rate the battery is experiencing

my 2020 Taycan when plugged into a 48 amp EVSE (60 amp breaker) would show 10.4 kW inside the car, and the EVSE would show 48 amps being delivered "raw"

my 2020 Taycan plugged into the Porsche mobile charger on a NEMA 14-50 outlet (50 amp breaker) 40 amp charge rate shows 8.3 kW inside the car and 9.6 kW/40 amps at the EVSE…

it really quite simple - Porsche is and has been updating Taycans to limit the North American vehicle's OBC's to max of 40 amps - this _IS_ a change in behavior for 2020-2024 Taycan's which used to happily handle a full 48 amps…

Porsche's OTA updates and service software being installed in North American Taycan's is setting the charging limit of the OBC to 40 amps - empirical and observed behavior demonstrate a higher limit prior to the latest factory software versions - this factual and beyond dispute - and there are posts on this forum dating back to spring of 2020 demonstrating 11 kW charging for Taycans with non-Porsche EVSE's and Porsche Wall chargers…

don't over think it

 

[RAHRCR]

If you have a J1.1, I'd be curious to know what you find after today's OTA update.

Oh boy.....this note makes me want to hold off! I haven't received notice of an available OTA update via the PCM though.....I will ping the chat once I charge after the update.

 

[MaxPlastix]

The installed L2 chargers at our (US) business center have 208v (commercial 3-phase source).

The EVSE advertises 80% Duty Cycle at the J1772 Pilot Signal (80x0.6), for 48A available. They are hardwired to 60A breakers.

Last week, my '24 Taycan 4S would draw over 9kW from this. Now, if they have limited the car OBC to 40A draw (?) my charge rate will max out lower than 8.3kW at the same ports.

Is the net change from this OTA that they reduced the max current from 45A to 40A?

 

[MaxPlastix]

I think you're making this too complex

208V in North America is not 3 phase coming out out the EVSe - there are not enough pins in the J-1772 to delivery 3-phase AC power…

Right? I think most people know that. What I mean is that most commercial EVSE provide 208v because they are two taps off the 3-phase Wye. And 208v vs 240v is not relevant to the car/EVSE negotiation.

Porsched vehicle charging software has _NEVER_ reported the raw power delivered by the EVSE inside the vehicle - it's alwasy been the effective charge rate the battery is experiencing

Agreed. I have to use an external monitor or information to see what the car and EVSE negotiated.

it really quite simple - Porsche is and has been updating Taycans to limit the North American vehicle's OBC's to max of 40 amps - this _IS_ a change in behavior for 2020-2024 Taycan's which used to happily handle a full 48 amps…

don't over think it

I will now have extra time to overthink it, as it represents a significant reduction in charging speed from my most-used chargers.

Was the old OBC's max really 48A? It seemed like the car took 45A, but I never checked the current on these faster L2 chargers (where 48A was offered).

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