Option7

Thanks for the input from your experience with 120v charging. It definitely will be extremely slow but I hope I can better understand why Porsche warns customers only to use the 120v charger in emergencies and never for more than 12 hours. If I will only get 4-6 miles per hour charging at 120v, that is understood but I hope to find out from a Porsche factory engineer why they don't want customers to leave their Taycan on the 120V charger for more than 12 hours. That makes no sense unless Porsche believes it will damage the charger, the main battery or the 12V auxiliary battery that runs the electronics in vehicle. So far the main battery showed zero charge loss after 2 weeks of sitting while were on vacation connected to nothing. We left at 76% and 163 miles and returned at 76% and 163 miles. So far my Taycan is perfect so I will follow Porsche's guidelines just to be safe.

flygdchman

Digging into it a little further I think that the concern is not with the car but the house. The concern is pulling a sustained load on a circuit that might be sharing other loads.

https://cleantechnica.com/2023/01/27...ant%20you%20to

Our Niro draws 12 amps which would be the full 80% allowed on a sustained basis for 15 amp circuit.

In my garage I have 20 amp circuits. Which are fed by a 240v circuit that has 40 amp capacity (8-3 NM-B) running through the house.

Haven't set up the 220V charger yet because I want to increase the house's wiring to have 55 amp capacity (6-3 NM-B) (I dumbly thought the 8-3 had 50 amp capacity)

The other reason to not run 120v is that it is inefficient.

Option7

I have a dedicated 20A circuit in my garage which only has the garage door opener on it.
If sharing this circuit was considered a problem to Porsche then the breaker would trip any time I open or close the garage door during charging.
If you are using the correct NEMA 20A plug with a 20amp breaker & 12/2 wire then this is not an issue but Porsche doesn't say this. Porsche says not to use their 120V charger for anything but emergencies and never for more than 12 hours. Porsche must say why this is the case. I expect there is something that extended charging at 120V causes damage to the main battery which risks battery fires, the auxiliary battery drains too much during charging in excess of 12 hours or it damages the onboard charger or the external Porsche charger. If they were worried the Porsche 120V charger would be damaged with extended daily use greater than 12 hours then they would be saying a better 120V charger from a 3rd party is better than Porsche unit. I doubt this. There is something Porsche is not saying that had them concerned to change their low voltage charging rules two years after introducing the Taycan. If they say there is a problem with their 120V charging not being as safe as originally marketed so rather than paying big for a recall of the onboard chargers, battery packs or Porsche 120V external chargers. They simply said it's still ok to use the 120V charger as long as you don't use it more than 12 hours, do not charge at 120v daily and only charge at 120V in emergencies to get just enough charge to get to a 220v charging station. I still smell an underlying issue Porsche is hiding.
I will eventually find out if I have to analyze the design and circuitry being used in the onboard charger, the auxiliary battery and its charging methodology or the high voltage battery pack from LG. I may have to speak with LG battery design engineers to understand the potential issues with long term low voltage charging of their batteries. Obviously Porsche does not want us to know this or they would be more forthcoming...

usctrojanGT3

That's interesting that you haven't lost charge leaving the car for a few weeks. I've sometimes lost 2-3% after not driving the car for 24-48 hours.

flygdchman

Well there may be something unique to the Porsche. Been charging our Kia Niro EV nearly exclusively on our 120V for the last 9 months and 10K miles.

Option7

I wonder if leaving the car outside in the sun where it can heat up or get cold in the winter that the car uses energy to keep the batteries at the optimum temp. Maybe your keys are too close to your car when it's parked so the keys & the car constantly talk to each other which would use battery power a bit.
I was told not to communicate with the car while you away since this will wake up the electronics in the vehicle and drain power from the auxiliary battery which will in turn get charged by the main battery as long as you are above 50%. I think below 50% charge the auxiliary battery will drain a few percent per day if the cake gets woken up multiple times per day. How many miles on your Taycan? Mine has 30K so I was surprised it didn't drop the range after 2 weeks.

Option7

I'm sure Porsche has good reason to tell customers 120V charging is only for emergencies and to charge no more than 12 hours when you do...

usctrojanGT3

I'd say that the keys are above 30-40 feet from the car. I have over 17k miles on my Taycan in less than a year as I use it for my realtor duties. I'm picking up my GTS ST on Thursday from PEC LA and I'll be selling the GTS in Jan as I took full bonus depreciation on it in 2022 so it'll be sitting no racking up anymore miles until I sell it.

Option7

I can afford new cars but I like to keep my cars indefinitely. I have 6 cars in my collection and looking for more. I buy beautiful cars that I don't put many miles on and keep them maintained perfectly, not a scratch or dent on any of them. I have the space to collect cars so it's important to know the cost to replace/rebuild engines or to replace batteries if the unexpected happens. EVs are a wildcard at this point. Luckily it doesn't really matter to me if used Taycan's drop in value significantly because the batteries end up $50K to replace or Porsche stops supporting their batteries. ICE vehicles can be repaired forever. A buddy of mine has a 1986 911 which is in mint condition and valued more than what he paid back in 1986. I don't expect this for the Taycan since I'll be dead in 25-30 years or I won't care. People that put a lot of miles on their vehicles during the warranty period usually need to keep turning over their vehicles since they can get beat up with heavy use. I'm happy I don't need to drive that much since I am fly for business 75% of the time. I drive mostly rental cars so when I get home driving the vehicles in my collection for a few days is a treat.

whiz944

I suspect the reason is that Porsche has no control over the receptacles their customers plug into. I've had old receptacles and switches literally crumble in my hands.

If you ever hold in your hand a cheapo "residential spec" receptacle, and compare it to a "commercial spec" (or industrial or hospital spec) receptacle, you'll immediately see and feel the difference. The residential quality come in 10-packs for like $5, whereas the commercial quality receptacles are like $5 each. So it is obvious which ones a typical home builder will use - the cheapest possible. They also do things like use the back stab holes for the wires, which have little knives that cut into the conductors, instead of proper screw down clamps. Saves a good 30 seconds per receptacle during installation.

If anyone is doing 120V charging on a regular basis, I strongly recommend using a commercial spec receptacle, and make sure it is wired using screw down clamps.

Option7

You are definitely correct about typical cheap plugs used by contractors. I'm an electrician & electrical engineer so I can add a few more pieces of information. Only 15A residential plugs have the quick connects. Leviton makes both commercial and residential grade NEMA 5-20 receptacles which only have screw terminals and both are rated for continuous use on a 20A circuit using 12/2 Romex, Bx or single conductors with a ground in EMT.
Commercial grade plugs are a bit stronger to take more physical abuse but are no different in terms of electrical performance.
If Porsche wanted to insure their customers only used the right receptacle they should simply spec NEMA 5-20P receptacles since you can only use a NEMA 5-20P plug in these outlets.
If a customer is using a NEMA 5-15 receptacle on 14/2 wiring with the quick connects or the screws they will have a problem even with a dedicated circuit because these plugs are designed for 15A not 20A.
I asked Porsche specifically if I could use their 120v charger on a dedicated 20A circuit with a NEMA 5-20 receptacle for continuous 120V (trickle charging my Taycan since it's so slow). The Porsche 3rd party electrical service installer they connected me with said "no", the service bulletin issued by Porsche in late 2021 does not mean you can use a commercial grade receptacle, wiring & breaker to charge daily or for more than 12 hours. I asked why but he said he didn't know. This statement by Porsche clearly means they are protecting their product, not the customer's potential lack of quality electrical components in their garage.
I will be going to Porsche in Germany in early 2024 for some technical discussions on other advanced technology development topics. Hopefully I will get to the bottom of this once and for all so I know why this policy was put in place several years after the first vehicles were delivered without this new policy.
I am hoping you are correct and they are just being very conservative and the local service & sales people are just being given simple instructions to educate customers to follow.
My local dealership did not remember ever seeing this service bulletin and said they simply don't recall any Taycan buyer not having a dedicated 220v circuit installed in their garages to charge only at 220V.
This is understandable but unfortunately my home is in an association with a detached garage across a driveway controlled by the association. The association will not allow homeowners to run a dedicated 220v line to their garage so I'm stuck with a dedicated 120V line and the hope I can change the association's mind or decide to buy another home sooner with 220V in the garage for my Taycan and park only my ICE vehicles in my current garage which is closer to the airports I fly in/out of every week or two.
I love my Taycan but as an engineer I still have a few questions to get answered...

MaxLTV

Battery manufacturing costs are going down by 10%-20% annually. I've seen dept of energy numbers of $153 per kwh in 2022 and is expected to reach below $100 per kWh sometime in 2025, all while improving the quality - size, longevity, etc. So the cost of the battery being under $10K in less than two years and continuing to drop after that is reassuring. Of course, we don't know what markup Porsche will build in, but anything crazy will get wide negative publicity - there are plenty of journos ready to stoke battery replacement cost hysteria. So I suspect/hope it will be reasonable, as in under $20K in today's money. Also, 8 year warranty does not mean the battery will fail in 8 years. We've seen teslas with older batteries be fine, and newer batteries and their temperature control systems are better, so should last even longer.

Option7

I do hope you are right. Porsche will charge more but I believe not to the point they turn every Porsche EV into a disposable vehicle no matter how well kept, low mileage and great looks these cars will continue to be. I used to always say a vehicle that is still beautiful when it's shape, even with a coat of dust or dirt on it still evokes emotion. Porsche has this beauty thing in spades. I get stopped every time I go into town by people who love my Taycan, my Boxster, my 911, all because they love the car, the paint, the details regardless if it is new or 20+ years old. That's hard to do but Porsche does this with style & performance over time. I don't expect they want their EV's to be any different.

whiz944

Commercial quality receptacles have a steel band from the top mounting hole, down the back of the receptacle, and to the bottom hole. Plastic quality is better. Wire clamping is better. And internally there are more "wipes" contacting the plug blades. So they are definitely more robust both in terms of continually plugging/unplugging, and in electrical reliability.

Most 120V EVSEs tell the car to limit current draw to 12 amps - which is 80% of 15 amps. This derating to 80% is a NEC requirement for continuous loads. If you want to pull a continuous 16 amps from a 5-20, you'll need a different EVSE. (The Tesla Mobile Connector is one such example. It has an optional NEMA 5-20 adapter available for this purpose. I think @daveo4porsche has tested this with his Taycan and a TeslaTap adapter.)

daveo4porsche

there is NO power supply cable option with Porsche PMC+/PMCC for a NEMA 5-20 powersupply cable (20 amp 120V circuit for 16 amp charging rate 1.92 kW) - I have tested my 2020 Taycan with a Tesla UMC Gen1 with a NEMA 5-20 plug and a NEMA 5-20 outlet - the Taycan charged at the expected rate for a 20 amp circuit with a 16 amp charge rate (if memory serves it was about 1.68 kW reported by the vehicle center screen vs. teh 1.92 kW "raw" charge rate). I have also tested Taycan with a NEMA TT-30 (120V 30 amp 24 amp charge rate - 2.88 kW raw)- and it worked with that as well. Based on my limited testing the Taycan will charge at most any rate as appropriate for 120/240V based on the AMP's reported by the EVSE

this is as opposed to my 2017 and 2019 Chevy Bolt which is limited to 12 amp maximum charge rate on any/all 120V EVSE's - the Bolt also defaults to 8 amps for _ALL_ 120V EVSE's and must be manually overridden and configured to do 12 amps…I haven't owned a Bolt since 2020 - so I have no idea if Chevy has recently changed this limitation.

if you have an EVSE that offers power - Taycan seems ready and willing to take any amount of power as reported by the EVSE - YMMV.