NEMA 14-50 Supply cable heat data

[daveo4EV]

hmmmmm - math…

18.5 kWh power delivered
time: 1:56 minutes

18.5 kWh / 1.93 hours = 9.58 kW/hour

9.58 kW / 39.8 amps = 240 volts!!

Voltage is in line with expectations - hmmmmm

ambient temperature in the garage? is the wire in the porsche dock enclosure?

I'd love to know the actual wire temps - do you have meat thermometer? or perhaps an infrared temp measurement unit? like this?

https://www.amazon.com/gp/product/B07VSHR9M6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

it would be wonderful to get some actual temperatures!! like where I measured my units. Is the cord from the PMCC to the car too hot to touch? or perhaps the J-1772 plug in the car?

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[KenU]

partially

during the charging session - the center console battery-charge UI can show either miles/min or kW

what is the kW during the charge cycle?

since

watts = amps * volts

if I have watts and amps I can do algebra and get an estimate as to the Volts ;-)

I'm wondering if your voltage is particularly "high" causing additional load on Porsche's under-spec wire.

Other than what I showed you on the display screen where else would the kW be seen? I just ended the charge and the screen was at 24.3 kWh at 2 hours.
Not sure where I'd look other than what's on the display.

 

[daveo4EV]

post #136 - your voltage is inline with expectations - I was thinking if you were getting 260 volts that would be 39.8 * 260 or 10.34 kW - which would explain why your cable was getting so hot -but your numbers are indicating 240 volts which is appropriate - so much for that theory...

I think the cable just sucks - yours might have a defect making things worse - it's hard to say how much worse your cable thermals are with out actual temperature measures to compare to other's like mine on post #1…

in any case it's pretty clear to me Porsche has made a sub-optimal wire gauge choice for their NEMA 14-50 supply cable and they should probably fix it.

 

[KenU]

hmmmmm - math…

18.5 kWh power delivered
time: 1:56 minutes

18.5 kWh / 1.93 hours = 9.58 kW/hour

9.58 kW / 39.8 amps = 240 volts!!

Voltage is in line with expectations - hmmmmm

ambient temperature in the garage? is the wire in the porsche dock enclosure?

I'd love to know the actual wire temps - do you have meat thermometer? or perhaps an infrared temp measurement unit? like this?

https://www.amazon.com/gp/product/B07VSHR9M6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

it would be wonderful to get some actual temperatures!! like where I measured my units. Is the cord from the PMCC to the car too hot to touch? or perhaps the J-1772 plug in the car?

Cable to the car was very warm but not hot to the touch. I plan on going to Home Depot tomorrow to get the infrared temp thermometer. Garage temp is 91 degrees and wiring is inside PMCC enclosure.

 

[KenU]

Other than what I showed you on the display screen where else would the kW be seen? I just ended the charge and the screen was at 24.3 kWh at 2 hours.
Not sure where I'd look other than what's on the display.

Sorry, I ended the charge at 2 hours 36 mins. Not 2 hours.

 

[daveo4EV]

Garage temp is 91 degrees

that's warm - my wire temps were 120-162 in ambient temps of 67F - your ambient temps are 25F hotter - which means your temps could be 145-187F - which is quite hot - but still "safe" for 105C rated cable - but certainly a bad choice for a mobile device designed to be handled/touched by humans…

 

[daveo4EV]

105C = 221F

cable is rated for use in ambient temps of -22F to 122F - cable is rated 221F - which means the cable is safe for a temperature rise of 221F - 122F - or 99F temperature heat factor…

in my local conditions I saw a maximum rise of 164F - 68F - 96F when under a 40 amp load…

91F (@KenU ambient temps) + 96F temperature rise (like I saw in my testing) = 91F + 96F or 187F as a possible temperature for the supply cable.

wow - that's super hot but still 34F less than max rating for the cable.

 

[wmras]

Cable to the car was very warm but not hot to the touch. I plan on going to Home Depot tomorrow to get the infrared temp thermometer. Garage temp is 91 degrees and wiring is inside PMCC enclosure.

Ken,
The PMCC limits the current to 40 amps, so the input cable is radiating the same heat (power). The fact that you can touch it at all suggests the temperature might be lower. More importantly, the #4-gauge wire has less voltage loss and therefore delivers more kWh to your car battery.
Am very interested in seeing a temperature measurement. And your installation is safer.
Your efforts clearly demonstrate the problem with the Porsche input cable.

 

[wemct]

I got my car and charger back from the dealership but unfortunately my service tech left before I got there so I didn't get the dealer's temperature readings from the days the car was with them. They said they'll get it to me on Monday.

Before I brought my car in I took temperature readings at the plug, the top of the PMCC where the adapter cable comes out, and at my 50 amp circuit breaker. Here are my readings compared to @daveo4EV although I wasn't as comprehensive in logging my readings.. My temps are reflected in green (40 amp charging) and blue (32 amp charging). Most troubling to me is that my circuit breaker was 155F at its hottest point.

Although dealer said Porsche's position is that car and charger are "operating within normal limits" at least I got the WLG2 software updates while it was there.

I'll take more readings next time I charge but next step is for me to get my electrician back out to redo wiring in my NEMA 14-50 receptacle to reduce amount of bends in wiring per dealer's electrician's recommendation..

I took some temperature readings earlier today. The ambient air temperature in the garage was 89F (31.6C) in hot Atlanta. The PMCC was pulling between 39.7-39.9 amps. The temperatures were stable after 2 hours. The hottest temperature was the 14-50R plug where it met the outlet. I was still able to hand hold the supply cable.

 

[KenU]

Thanks for that! Love that color!!!

Standby for mine in an hour or so...just started charging, have the infrared thermometer on hand tonight!

Bringin’ the marshmallows too!

 

[KenU]

Ok, this is about 1hr 40 mins in (I don't have the graphic skills you guys have):

Double 50A breaker at panel: top half is 105* bottom is 96* (70 ft 4 gauge wire)

Garage temp: 91*

Receptacle: 122*

Plug: 145*+

Supply cable right above plug: fluctuated between 147-154*, when shot a few more times it was mostly in the 147-150* range

Supply cable at the top curve: 130*

PCCM: 112*

Cable directly underneath PCCM: 126*

Cable to car: 114*
Car plug: 110*

Are these in "Normal" range??

I'll check back there in about 20-30 minutes and re-shoot

 

[KenU]

Ok, this is about 1hr 40 mins in (I don't have the graphic skills you guys have):

After 2hrs 25 mins:

Double 50A breaker at panel: top half is 105*/ 104* bottom is 96*/ 97* (70 ft 4 gauge wire)

Garage temp: 91*/ same

Receptacle: 122*/ 128*

Plug: 145*+/ 150*

Supply cable right above plug: fluctuated between 147-154*/ 153*, when shot a few more times it was mostly in the 147-150* range

Supply cable at the top curve: 130*/ 121*

PCCM: 112*/ 109*

Cable directly underneath PCCM: 126*/ 127*

Cable to car: 114*/ 119*
Car plug: 110*/ 108*

Are these in "Normal" ranges??

 

[wmras]

These temperature measurements are lower than I expected, except for the plug. None are unsafe unless you try to unplug it immediately after turning it off. The high plug temperature suggests a poor connection inside or with the receptacle. Did not expect the middle of the cable to be so much cooler.
Was the dock door closed and 40 amps flowing the entire time (except when measuring)?

 

[KenU]

These temperature measurements are lower than I expected, except for the plug. None are unsafe unless you try to unplug it immediately after turning it off. The high plug temperature suggests a poor connection inside or with the receptacle. Did not expect the middle of the cable to be so much cooler.
Was the dock door closed and 40 amps flowing the entire time (except when measuring)?

Dock door open at all times, 40 amps entire charge. Are you saying the connection from the 4 gauge to the receptacle may be a poor connection or a poor connection somewhere else? And forgot to say the temp at the 4 gauge out of the wall into the receptacle was 104*, if that means anything. Thanks again

 

[wemct]

M

These temperature measurements are lower than I expected, except for the plug. None are unsafe unless you try to unplug it immediately after turning it off. The high plug temperature suggests a poor connection inside or with the receptacle. Did not expect the middle of the cable to be so much cooler.
Was the dock door closed and 40 amps flowing the entire time (except when measuring)?

My plug temp was also 145F (similar to @KenU). The flat portion was cooler. The biggest difference between our readings was the supply cable right above the plug. Mine was about 133F. In light of the fact that both garages are very warm, most of the temps don't seem too bad if the limit is 212F. You can hand hold 133F.

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