US Porsche PMC+ Tripping GFCI Breaker on 120v outlet

[AaranZombot]

to see if you're circuit for example you can take the EV/EVSE-charger to another plug at a friends house and see if it works there with out tripping the breaker

basically to isolate anything in life - you need to debug it - you debug things by swapping the one thing that may be the problem with another thing and see if the same problem occurs - there are 5 things that could be a problem here

1. the EV charger (EVSE) could be the problem - you need to try another non-Porsche EVSE to see if it's the Porsche charger that is the problem
2. the EV itself - can the Porsche EVSE charge a different EV - you can charge any EV with any EVSE - can your Porsche EVSE charge a different EV on the same ciruict/outlet?
3. the actual GFI plug in the wall (GFI plugs are notoriously finicky)
   1. I'd try another GFI plug
      1. NOTE: on some 120V circuit there are multiple GFI plugs (more than one plug served by the same breaker) - with GFI a weak/broken/finicky GFI plug _ANYWHERE_ on the same circuitcan cause a fault and the plugs to "trip" - this one of the hardest things about GFI it may not be the plug you're using that's the problem.
   2. I'd try a non-GFI plug - it may just be an interaction with GFI and the Porsche EVSE.
4. the circuit breaker could be problem (possible but unlikely)
5. the wiring on this circuit could be bad -try an entirely different 120V circuit (different breaker) in your home

with out isolation of the 5 elements and trying each different element in a controlled fashion you can not diagnose root cause of wht is the problem - this is a fact.

if I was a betting man the two most likely problems are:

1. the Porsche EV charger (the EVSE) - they are known to be finicky
2. the GTI outlet might be finicky and swapping it for a new one might

the other 3 elements are possible problems, but not typical and would be a surprise outcome.

start with getting the Macan to charge with another non-Porsche EVSE on the same outlet in your home _OR_ get the Macan to charge with the Porsche EVSE at a different 120V outlet (friends house or work) or even other breaker/outlet in your home (non-GFI is where I'd start).

good luck - but you'll need to test each element to find out what is the likely cause.

but remember Porsche really really doesn't like customer using 120V charging for daily use their own technical bulletin recommends against it…

Charges fine on another outlet in the garage (non-GFI) in a non-ideal location.

 

[daveo4EV]

Charges fine on another outlet in the garage (non-GFI) in a non-ideal location.

good news not the EVSE or the vehicle!

most likely the gfi outlet itself - replace with a commercial/garage/outdoor rated gfi outlet- easy peasy swap less than $40 at lowe’s/home depot

or just use the tesla charger to charge the macan

but porsche really doesn’t like owners charging on 110vokts as a common practice - see tech note i linked earlier!

 

[AaranZombot]

daveo4EV
has the right idea; if the actual circuit breaker is not tripping it is not an over current and is probably a issue with the GFCI itself or how the charger is interacting with the GFCI. If the GFCI is old or an off brand try changing it out for a Leviton.

Electrician came on Friday and when I plugged the PMC+ into the GFCI outlet it didn't trip the outlet and starting charging - arghh.... We did it about 4 times and it never tripped. He said it was likely a finicky GFCI, even though it's relatively new, and could replace with the highest quality. Charged the rest of the day before a roadtrip on that outlet with no problems.

Returned on Sunday, plugged in and immediately the GFCI tripped. The probably only happened about once a month or two months on the Tesla and it was always related to it raining outside.

The outlet in the garage without a GFCI is not a reasonable spot to use so I think I'm going to have a 220 installed. Additionally, the Porsche charges SO much slower on a 120v than the Tesla MY did. It only went up 10% plugged in from 7pm to 7am. The screen said 1.4kw, I think the Tesla charger did 5kw.

 

[Dragon Tourniquet]

Electrician came on Friday and when I plugged the PMC+ into the GFCI outlet it didn't trip the outlet and starting charging - arghh.... We did it about 4 times and it never tripped. He said it was likely a finicky GFCI, even though it's relatively new, and could replace with the highest quality. Charged the rest of the day before a roadtrip on that outlet with no problems.

Returned on Sunday, plugged in and immediately the GFCI tripped. The probably only happened about once a month or two months on the Tesla and it was always related to it raining outside.

The outlet in the garage without a GFCI is not a reasonable spot to use so I think I'm going to have a 220 installed. Additionally, the Porsche charges SO much slower on a 120v than the Tesla MY did. It only went up 10% plugged in from 7pm to 7am. The screen said 1.4kw, I think the Tesla charger did 5kw.

Couldn't have been doing 5kw, because that would be 41.7 amps pulled at 120V. At most, if it was a 20A rated circuit, it could have done 2.4kw.

 

[AaranZombot]

Couldn't have been doing 5kw, because that would be 41.7 amps pulled at 120V. At most, if it was a 20A rated circuit, it could have done 2.4kw.

Fair point. I am not sure I logged the kw but it was definitely faster than the Macan. I could usually get about 60 miles of charge in 12 hours (sometimes more) and the Macan only got around 20-30 in 12 hours.

 

[daveo4EV]

Fair point. I am not sure I logged the kw but it was definitely faster than the Macan. I could usually get about 60 miles of charge in 12 hours (sometimes more) and the Macan only got around 20-30 in 12 hours.

need to compare kWh's. - that's the only "fair/accurate" comparison - Tesla lies about miles added per-charge (miles per-hour of charge will vary based on actual consumption which depends on a lot of factors - so there is no actual accurate way to evaluate miles added per-charge) - Tesla's numbers are "inflated/optimistic" in terms of miles "added" (they have been successfully sued over this fact) - kWh is the "truth" - and all things being equal the Macan/Tesla are charging at the same rate from the same breaker/circuit - it can not be any other way…also battery percentage added is also apples to oranges - because the batteries are different sizes

10% of 75 kWh battery is 7.5 kWh (5.2 hours of charging at 1.44 kW)
10% of a 95 kWh battery is 9.5 kWh (6.59 hours of charging at 1.44 kW)

so yeah for 1 hour of charging at 1.44 kW you will add 2% battery to a Tesla and 1.5% battery to a Macan…

the charge rate is "fixed" it has to be - its how electricity works - but the miles added and percent of battery depends on the characteristics of the EV and it's battery…

1 hour of charging at 1.44 kW adds about 1.3 kWh to both the Tesla and Macan battery:

1.33 kWh is 1.77% of a Tesla battery and 5.32 miles of range best case
1.33 kWh is 1.44% of a Macan battery and 4.09 miles of range typical case

same amount of power, same bill on your electrical meter, same EVSE, same NEMA 5-15 circuit - but two different ranges and % capacities even though the charge rate and circuit are identical.

the formula for electricity is simple

watts = volts * amps

volts in North America is either 120V or 240V
amps is the number on your circuit breaker for the plug-outlet (typically 15 or 20 amps on Residential circuits)

120 volts * 15 amps = 1,800 watts (raw NEMA 5-15 circuit capacity) 1.8 kilowatts (kW)

NOTE: NEMA 5-15 outlets can be on on _ANY_ size breaker - and therefore are sometimes on 20/30 amp breakers - this will _NOT_ increase the "draw/current" for a NEMA 5-15 outlet - since the appliance/device plugged into a NEMA 5-15 outlet has no way to "know" it's has 20/30 amp breaker - having 20/30 amp breakers on 120V outlets is more about increasing the total capacity to be shared between multiple NEMA 5-15 outlets sharing the same breaker, but no single outlet will typically "draw" more than 15 amps - since that is the expected/rated maximum load for a single NEMA 5-15 outlet. If you have 120V circuit with 20/30/40 amp breaker - you should also have a different type of outlet NEMA 5-20, 6-20, 5-30, 6-30 - this indicates to appliance/devices that they can draw more power - but the plug shape is different and your normal plug type will not "fit" into this higher capacity outlets - this is by design and the source of much confusion.

EVSE's can only use 80% of the rated circuit capacity

80% * 15 amps = 12 amps capacity available for an EVSE (this is true for ALL EVSEs and is not vendor specific - it's electrical building code).

120 volts * 12 amps = 1,440 watts - or 1.44 kW raw capacity for charging an EV from a NEMA 5-15 outlet.

so both the Tesla EVSE and the Porsche EVSE plugged into a NEMA 5-15 outlet (GFI or otherwise) can provide a maximum of 1.44 kW to any EV they are plugged into - typically there is 7-12% loss in charging overhead (AC/DC conversion, heat, wire resistance, etc) - so typically 1.44 kW "raw" charging capacity ends up only providing 1.33 to 1.26 kW actual battery charge rate…

1.33 kW for one hour is 1.33 kWh (kilowatt hours) added to the battery for every hour charged.

 

[CandianPorsche83]

need to compare kWh's. - that's the only "fair/accurate" comparison - Tesla lies about miles added per-charge (miles per-hour of charge will vary based on actual consumption which depends on a lot of factors - so there is no actual accurate way to evaluate miles added per-charge) - their numbers are "inflated/optimistic" in terms of miles "added" - kWh is the "truth" - and all things being equal the Macan/Tesla are charging at the same rate from the same breaker/circuit - it can not be any other way…also battery percentage added is also apples to oranges - because the batteries are different sizes

10% of 75 kWh battery is 7.5 kWh (5.2 hours of charging at 1.44 kW)
10% of a 95 kWh battery is 9.5 kWh (6.59 hours of charging at 1.44 kW)

so yeah for 1 hour of charging at 1.44 kW you will add 2% battery to a Tesla and 1.5% battery to a Macan…

the charge rate is "fixed" it has to be - its how electricity works - but the miles added and percent of battery depends on the characteristics of the EV and it's battery…

the formula for electricity is simple

watts = volts * amps

volts in North America is either 120V or 240V
amps is the number on your circuit breaker for the plug-outlet (typically 15 or 20 amps on Residential circuits)

120 volts * 15 amps = 1,800 watts (raw NEMA 5-15 circuit capacity) 1.8 kilowatts (kW)

EVSE's can only use 80% of the rated circuit capacity

80% * 15 amps = 12 amps capacity available for an EVSE (this is true for ALL EVSEs and is not vendor specific - it's electrical building code).

120 volts * 12 amps = 1,440 watts - or 1.44 kW raw capacity for charging an EV from a NEMA 5-15 outlet.

so both the Tesla EVSE and the Porsche EVSE plugged into a NEMA 5-15 outlet (GFI or otherwise) can provide a maximum of 1.44 kW to any EV they are plugged into - typically there is 7-12% loss in charging overhead (AC/DC conversion, heat, wire resistance, etc) - so typically 1.44 kW "raw" charging capacity ends up only providing 1.33 to 1.26 kW actual battery charge rate…

1.33 kW for one hour is 1.33 kWh (kilowatt hours) added to the battery for every hour charged.

@daveo4EV YOU are the "truth"

 

[daveo4EV]

Fair point. I am not sure I logged the kw but it was definitely faster than the Macan. I could usually get about 60 miles of charge in 12 hours (sometimes more) and the Macan only got around 20-30 in 12 hours.

if you use 4 miles/kwh as the estimate factor

60 miles of range is 15 kWh
15 kWh @ 1.3 kW charger rate (1.44 kW * 90% charging efficiency) 11.5 hours

Macan Turbo just went 293 miles from full to 0% - and we know it's 95 kWh "usable" capacity

so 293 miles in 95 kWh is 3.08 miles / kWh efficiency

12 hours of charging at 1.3 kwh is 15.6 kWh added to the battery

15.6 kWh * 3.08 miles/kWh= 48.048 miles of estimate range…this is the Macan's expected range for 12 hours @ 1.44 kWh on a NEMA 5-15 outlet.

the Tesla number is optimistic/ideal - but both Model Y/Model 3 are close to 4 miles/kWh efficiency (they are great)
the Macan number is closer to reality and is inline with 3 miles/kWh consumption

in both cases 12 hours of charging added about 15 kwh of capacity to the battery - but the two cars have very very different rates of consumption and will therefore show different mile estimates for the same amount of "power"…

• the charge rate is constant for a given electrical circuit
• the amount of power added to the battery is also constant for the same amount of time - there is no radical difference in efficiency for battery charging
• but no 2 EV's consume kWh's at the same rate - so number of miles "added" will be wildly different

no different than gas cars and one gallon of gasoline.

 

[daveo4EV]

* - also I believe the PMC/PMC+/PUC default to 50% charge rate on 120V outlet (this is for safety given the wide range of residential circuits in North America) - that means if you plug in a PMC/PMC+/PUC with a NEMA 5-15 power supply cable (household outlet) you will not get the "full" 1.44 kW capacity (which is maximum power for an EVSE on a normal North American residential circuit) - you will get 50%. of 1.44 kW or 720 watts or 0.72 kW - this is a difference between different EVSE's - and again can skew the numbers - which as we've seen can already be hard to compare…

the Chevy Bolt will enforce 50% charge rate from _ANY_ 120V/L1 EVSE and therefore will charge even slower than possible when using any L1 (120V) EVSE - this is from painful experience for GM/Chevy with Volt and other EV's where they learned that not all residential 120V circuits/outlets/wires/breakers are equal - and sometimes expecting optimal/ideal behavior from your typical residential home outlet is a bad assumption…and can lead to bad outcomes…fires, breakers tripping

120V outlets in North America are typically shared (multiple outlets sharing a single breaker) and as we all know sometimes the microwave is on the same circuit as the dishwasher - and adding a max power EVSE to the same circuit will simply cause the circuit breaker to trip constantly because the EVSE is consuming 80% of the available breaker capacity (1.44 kW) and then if the microwave is also turned on while the EV is charing that's another 1000 watts (at least maybe 1,500 watts) which is a total of 1.44 + 1.2 kW or 2,600 watts total - which is over current for the max rating of the circuit breaker (1.88 kW) and the circuit breaker does what it's designed to do and trips - causing the EV to stop charging and the microwave to not finish the pop-corn.

residential circuits are fraught with problems for EV charging and most are 20+ years old and were never designed/installed to run for 12-72 hours at full capacity…if you plugged in a 0% Macan and charged to 100% on a NEMA 5-15 outlet it would take 70+ hours to fully charge…

I promise you most/nearly all of the existing 120V circuits installed in North America are not properly provisioned to run at a full unrelenting 80% capacity for 70+ hours straight…it just wasn't part of the thinking for that type of usage…

for that type of usage you need:

• dedicated outlet - no shared multiple outlets on the same circuit breaker
• commercial/industrial quality NEMA 5-15/5-20 outlet
• commercial/industrial quality breaker
• 12/10/8 gauge wire - most residential circuits are 16/14 gauge wire
• all copper wire - not aluminum
• dedicated ground
• dedicated neutral

few if any existing residential NEMA 5-15 outlets meet the criteria listed above - and therefore are quite dicy to use for EV charging that can last for 12+ hours at nearly full capacity with no reduction in capacity demand during the charging session…

I recommend installing a properly designed dedicated circuit for charging an EV at home - it's the only way to know that everything is "up to snuff" in terms of being able to handle the load with out failure…and failure here means a likely outcome is an actual fire while you're sleeping because you mostly charge your EV overnight when power rates are lower…

really honestly this is not what you want to wake up to in the morning because you're using an existing 120V circuit that is shared with 6 other outlets to charge your EV overnight

 

[daveo4EV]

read this document published by Porsche - it is their best advice for installing a circuit for charging your EV - they were late to the party with this advice, but they finally got there - and by the way, every other EV vendor also has similar recommendations/requirement…

so don't believe me - fine dont' believe me - but you if you respect Porsche's engineering (and I think we all do) this document is their advice for residential charging in North America…NOTE: they recommend against using 120V/L1 charging for daily use.

https://static.nhtsa.gov/odi/tsbs/2022/MC-10222530-0001.pdf

Caution

If the electrical receptacles/outlets are not of sufficient quality, higher temperatures can occur in the receptacle when charging the vehicle using the supplied charging hardware (e.g. Porsche Mobile Charger). This can result in thermal damage to the receptacle and associated wiring. Low quality NEMA receptacle use or improper installation are not an indication of a defect in the vehicle or Porsche charging hardware.

General Precautions on (125V) Supply Cable Use

The “domestic” (125V) supply cable is provided for emergency use only, and should not be used by customers for daily home charging. Please discuss installation and use of a suitable 250V circuit with all customers.

Information

Caution

The surface of the charger and associated equipment can become very hot under normal use. This is normal and not an indication of a defect in the charger. Observe the operating instructions provided with the charger, particularly the warnings and safety instructions.

When used, it is recommended to limit 125V charging to a maximum of approximately 12 hours. Charge only to a minimum needed get to a nearest High-Power Charger (HPC) or DC Charger for recharging.

also attached to this posting in cases the link does not work.

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