[ANNOUNCED] - PMCC tech advisory : charging rate amperage lowered for "normal" usage of the PMCC (rate reduced by half)

[DerekS]

I've said this before but...just get a Wallbox.

It plugs into the same NEMA 14-50 outlet as Porsche's EVSE, and in the same orientation.

It has a good app and it will interface with my forthcoming Chargey app to automatically ingest your home charge costs.

I am super happy with mine.

Sponsored

 

[JimBob]

It should be clarified as there appear to be at several issues with respect to the PMCC.

The supply cable which gets hot.

The pins to the car which show signs of excessive heat. This appeared in the NHTSA report. This would likely be caused by either a faulty connection of the wire to the connector or wear on the pins where they connect with the car.

I have not seen any evidence that the unit itself is causing problems (just reporting them).

And one additional one which I have noticed. I have the cabinet and very occasionally when the door is shut and the garage is hot, it may show an error due to overheating. This is probably heat from the supply cable that is trapped by the cabinet. When the door is open, I don't get this error.

In any event, none of this should be happening in a properly functioning unit which should be able to handle all temperature ranges.

 

[daveo4EV]

In any event, none of this should be happening in a properly functioning designed unit which should be able to handle all temperature ranges.

the PMC+/PMCC units are functioning correctly given their designs -the problem here is the design is lacking…

these issues are not a defect that can be addressed by Porsche as a warranty issue - the North American PMC+/PMCC have design/specification issues that leave them subject to these limitations - the only solution is to either run them at lower settings or obtain a properly designed EVSE from another vendor.

the PMC+/PMCC are lacking in design thoroughness to allow them to operate reliably in a wide range for foreseeable circumstances - this is a disappointing shortfall from a company with Porsche's reputation but clearly demonstrates their lack of experience in the EV market segment.

my and other recomendation is to obtain a quality product for your Taycan from another EVSE vendor.

 

[OhRichman]

LOL

you have purchase a $120+++ EV capable of charging at 11 kW (48 amps)
Porsche includes an EVSE that should do 9.6 kW (40 amps)
but they recommend you charge at 30 amps 7.2 kW or 4.8 kW (20 amps - 50% PMC+)

because Porsche can't design their cables or EVSE's to handle the proper electrical loads…

this is just pathetic…

if anyone has doubted the North American PMCC/PMC+ sucks as an EVSE - this tech bulletin should clear up their confusion.

Interestingly enough, I have a Taycan GTS with the PMC+ that was delivered in July of this year. It charges at 8.4 kW, which seems to imply 30 amps. Looks like they made an adjustment for new deliveries.

 

[daveo4EV]

Interestingly enough, I have a Taycan GTS with the PMC+ that was delivered in July of this year. It charges at 8.4 kW, which seems to imply 30 amps. Looks like they made an adjustment for new deliveries.

8.4 is the amount of power "hitting" the battery as reported by the center console inside the vehicle

9.6 kW is the "raw" amount of power the PMC+ is pulling from your electrical feed (240v @ 40 amps) - the Taycan does not show the "raw" power -it shows the power being added to the battery after "overhead".

the difference is the loss due to charging overhead and running other electronics in the vehicle…

8.4 kW is "inline" with expectations for a 40 amp feed from a 50 amp breaker @ ~230 volts… (9.2 kW)
9.6 kW raw is the "ideal" for 40 amps @ 240 volts…voltage varies so read on for gory details…

I personaly get 8.68 kW from my 9.6 kW EVSE - the difference between 8.68 and 8.4 can easily be explained by expected and normal variance in power grid voltage - North American ideal voltage is 240 volts - but in reality the power grid delivers anywhere from 210 to 250 volts depending on time of day, other loads on the system, age of the transformer on your pole, distance to the EVSE from your main panel, quality/gauge of the wire used, etc…

since watts is volts * amps

250 volts * 40 amps = 10,000 watts - 10 kW
240 volts * 40 amps = 9,600 watts - 9.6 kW
220 volts * 40 amps = 8,800 watts - 8.8 kW
210 volts * 40 amps = 8,400 watts - 8.4 kW

all of these voltages are inline with expectations for the North American grid and therefore can cause lower readings in your center console even though your EVSE is running at a full 40 amps

given your 8.4 kW reading I'm going to suggest your home voltage is running in the 220-230 volt range which is nominal and no cause for concern but not the ideal 240 volts that is modeled for planning purposes

there was a thread on this forum where it was discussed a Taycan owner was not seeing hte full 64 amps expected from a 80 amp charger (80 amp breaker = 64 amp charge rate) - and thought his Taycan was defective. Turns out the charger was installed on a commerical power feed in a shared HOA/Condo garage - commerical feeds in North America are typically 208 volts (rather than the residential 240 volt ideal) - the difference in 240 volt vs. 208 volts perfectly accounted for the "short fall" in charging speed - and once he plugged the vehicle into a full 240 volt feed at a family member's house the charge rate was "as expected" given the difference in voltage. No problem with the vehicle, but there can be wide variance of actual power delivery based on voltage which can vary for a wide variety of expected and normal fluctuations…

I can see as much as 10 volts higher voltage when charging early in the morning due to reduce load in the neighborhood vs. mid day…this kW stuff varies due to a number of factors.

 

[JimBob]

these issues are not a defect that can be addressed by Porsche as a warranty issue

I don't think this is right. Bulletin #: 2104.4 from NHTSA reporting overheating and discoloration at the charging socket is a potential warranty issue as it could be a safety issue. The bulletin itself reports that this is under investigation so you cannot preclude that it is not warrantable.

 

[OhRichman]

8.4 is the amount of power "hitting" the battery as reported by the center console inside the vehicle

9.6 kW is the "raw" amount of power the PMC+ is pulling from your electrical feed (240v @ 40 amps) - the Taycan does not show the "raw" power -it shows the power being added to the battery after "overhead".

the difference is the loss due to charging overhead and running other electronics in the vehicle…

8.4 kW is "inline" with expectations for a 40 amp feed from a 50 amp breaker @ ~230 volts… (9.2 kW)
9.6 kW raw is the "ideal" for 40 amps @ 240 volts…voltage varies so read on for gory details…

I personaly get 8.68 kW from my 9.6 kW EVSE - the difference between 8.68 and 8.4 can easily be explained by expected and normal variance in power grid voltage - North American ideal voltage is 240 volts - but in reality the power grid delivers anywhere from 210 to 250 volts depending on time of day, other loads on the system, age of the transformer on your pole, distance to the EVSE from your main panel, quality/gauge of the wire used, etc…

since watts is volts * amps

250 volts * 40 amps = 10,000 watts - 10 kW
240 volts * 40 amps = 9,600 watts - 9.6 kW
220 volts * 40 amps = 8,800 watts - 8.8 kW
210 volts * 40 amps = 8,400 watts - 8.4 kW

all of these voltages are inline with expectations for the North American grid and therefore can cause lower readings in your center console even though your EVSE is running at a full 40 amps

given your 8.4 kW reading I'm going to suggest your home voltage is running in the 220-230 volt range which is nominal and no cause for concern but not the ideal 240 volts that is modeled for planning purposes

there was a thread on this forum where it was discussed a Taycan owner was not seeing hte full 64 amps expected from a 80 amp charger (80 amp breaker = 64 amp charge rate) - and thought his Taycan was defective. Turns out the charger was installed on a commerical power feed in a shared HOA/Condo garage - commerical feeds in North America are typically 208 volts (rather than the residential 240 volt ideal) - the difference in 240 volt vs. 208 volts perfectly accounted for the "short fall" in charging speed - and once he plugged the vehicle into a full 240 volt feed at a family member's house the charge rate was "as expected" given the difference in voltage. No problem with the vehicle, but there can be wide variance of actual power delivery based on voltage which can vary for a wide variety of expected and normal fluctuations…

I can see as much as 10 volts higher voltage when charging early in the morning due to reduce load in the neighborhood vs. mid day…this kW stuff varies due to a number of factors.

Thanks for the explanation. This makes sense.

 

[daveo4EV]

I don't think this is right. Bulletin #: 2104.4 from NHTSA reporting overheating and discoloration at the charging socket is a potential warranty issue as it could be a safety issue. The bulletin itself reports that this is under investigation so you cannot preclude that it is not warrantable.

you are correct - for that issue it's a warranty issue- the overheating and lack of compatibility with non-Porsche EV is more in the category I was discussion

I think however we're splitting hairs besides identifiable warranty issues (that you note) we have a range of functional design issues that will not be addressed by an NHTSA bulletin

the PMC+/PMCC product line is irredeemably lost to me personally and a failed product in my opinion - nothing short of some new designs for a VW/Audi/Porsche EVSE is what is required - because even if/when we get an issue addressed such as the NHTSA bulletin we are still left with other issues as noted

there is more than enough evidence in my mind to suggest that the PMC+/PMCC is not a quality product and we should look elsewhere for our EVSE needs.

but I stand corrected @JimBob you are correct in addition to warranty issues as you note we also have design issues.

 

[XLR82XS]

FWIW I have 2 recalls getting taken care of in a couple weeks. Dealer advised to bring charger with me for one of the recalls. Doubt it will fix the overheat issue on 100% setting - fingers crossed.
('21 RWD)

 

[Deleted member 7736]

After reading through all of this I must say that even though I've only had my PMCC for a month or so and I've not had any problems with it so far, I'm still a bit disappointed to hear about all the problems others are experiencing. If I knew at the time of order config what I know now, I wouldn't have ordered a PMCC.

That said, I decided to reduce the charging amperage on my PMCC to 30 amps to give it a try, as it's been obscenely hot here recently and the temps in the garage, even in the middle of the night, are still in the 80's. First go last night. Car was at ~30% when I plugged it in. It's on a timer to start charging at midnight (cheapest time of use). When I woke up this morning the car was at 85% as specified, and ready to go. So in the real world, I'm not sure that reducing the charging amperage, either by choice or by reprogramming by the dealer, is something I'm going to lose any sleep over.

 

[daveo4EV]

FWIW I have 2 recalls getting taken care of in a couple weeks. Dealer advised to bring charger with me for one of the recalls. Doubt it will fix the overheat issue on 100% setting - fingers crossed.
('21 RWD)

no it won't fix the overheating problem - but they will attach a sticker to the charger suggesting you no longer run it at a full 40 amps and adjust the AMP settings lower to "fix" the problem…

this is like Porsche reporting the top speed of the Taycan is 163 mph - but when you encounter problems at that speed (say it overheats) the simply suggest driving at 1/2 speed instead - that the top speed really isn't 163mph -it's much lower.

 

[XLR82XS]

no it won't fix the overheating problem - but they will attach a sticker to the charger suggesting you no longer run it at a full 40 amps and adjust the AMP settings lower to "fix" the problem…

this is like Porsche reporting the top speed of the Taycan is 163 mph - but when you encounter problems at that speed (say it overheats) the simply suggest driving at 1/2 speed instead - that the top speed really isn't 163mph -it's much lower.

F a sticker! I wonder if they will ever release a new charging unit? As you and others have stated, it's not a great piece. ?

 

[daveo4EV]

After reading through all of this I must say that even though I've only had my PMCC for a month or so and I've not had any problems with it so far, I'm still a bit disappointed to hear about all the problems others are experiencing. If I knew at the time of order config what I know now, I wouldn't have ordered a PMCC.

That said, I decided to reduce the charging amperage on my PMCC to 30 amps to give it a try, as it's been obscenely hot here recently and the temps in the garage, even in the middle of the night, are still in the 80's. First go last night. Car was at ~30% when I plugged it in. It's on a timer to start charging at midnight (cheapest time of use). When I woke up this morning the car was at 85% as specified, and ready to go. So in the real world, I'm not sure that reducing the charging amperage, either by choice or by reprogramming by the dealer, is something I'm going to lose any sleep over.

you are correct - given sufficient time you can charge at any rate- and for most daily driving duty the charging difference between 30 amps and 40 amps is inconsequential since the car is still ready in the morning when you wake up.

some people on this very forum charge via household outlet and swear they are happy…

but it _IS_ a failure of design that the Porsche EVSE can not be used at it's rated/published/specified maximum rate - and should you need the vehicle to charge faster the PMCC/PMC+ are admittedly now and officially (according to Porsche) not capable of meeting their specifications reliably.

if you want a 40 amp EVSE Porsche has no offering - but the $200 Tesla Mobile Corded Connector will do the job and won't overheat.

it's also not hard to find a 40 amp EVSE that does this task with out overheating - in fact there are $200 units that do this day in and day out with zero issues - so this is a fairly public fail for something that is easily handled by "lesser" companies…this is not nearly has complex as the Taycan's blended braking, well understood, and easily fixed with some minor design changes, and yet Porsche has decided to reduce the units specifications rather than address the core issue…disappointment abounds for me personally and makes me question Porsche's commitment to this whole EV thing.

people laughed and me and accused me of being a troll when I suggested the PMCC/PMC+ sucked two years ago - well we've come full circle now - and Porsche's official answer in writing is a sticker and a new default AMP setting and an implied admission the PMC+/PMCC really aren't that great, but no actual fix or alternative product.

 

[Edward]

the difference is the loss due to charging overhead and running other electronics in the vehicle…

8.4 kW is "inline" with expectations for a 40 amp feed from a 50 amp breaker @ ~230 volts… (9.2 kW)
9.6 kW raw is the "ideal" for 40 amps @ 240 volts…voltage varies so read on for gory details…

Dave, you must be an EE. I studied EE and once upon a time could explain all about op amps, MOSFET circuits, etc. Nowadays, deriving 9.6 kW from Ohm's Law (240 V * 40 A = 9600 W) is about all I can do! ?

But you're right -- a 40 A load on a 50 A circuit is exactly in line with safety guidelines. A load should not exceed 80% of the max amp rating of the circuit breaker.

[EDIT] 8.6 kW is about the max my Taycan can draw from the EVSE also. I assumed parasitic or other carrying losses, as there's a lot of heat dissipated. It might start out at 9.6 kW from the wall side, but there's some serious thermal dissipation through the EVSE-to-car cable (expressed as x W or BTU of heat -- I forget the conversion.)

 

[Deleted member 7736]

(snip)…disappointment abounds for me personally and makes me question Porsche's commitment to this whole EV thing.

I'm at the point in my life that I choose not to worry about things that are essentially of no consequence to me. The car is awesome and the charger does what I need it to do. If/when the PMCC ever fails to meet my needs, the solution is just a couple hundred bucks for a new EVSE. Not sure I'm going to throw the baby out with the bathwater and start questioning Porsche's commitment to "the whole EV thing" because they didn't nail the design of the PMCC on the first go-round.

Sponsored