mikem33

HI,

If your charger plug gets very hot when charging at 40A, read on.

I have seen a number of discussions about the charger plug getting hot during charging. Mine was getting really hot. I was about to change the outlet (from discussions recommending Hubbell), but before that I decided to take some measurements. The outlet was not getting that hot; it was the plug.
I bought a ChargePoint Flex, and connected it and took some measurements as well. Both units were connected to the same outlet.

The short story:
Etron charger plug reaches close to 75 degrees Celsius in 10 minutes; after 20 minutes, the temperature is over 90 celsius; too hot to touch for more than a couple seconds! Cable close to plug is 65C, cooling to about 45C on the EVSE side. Charge cable is about 42.
ChargePoint charger reaches 42 celsius after a full hour and was warm to the touch. Charge cable is about 40 c; so is power cable right at the plug.

Both chargers were charging at 40A; car read 8.6KW for the Etron, and 8.8KW for the Chargepoint. Garage was at about 84F. (about 30C).

90C is unsafe. Romex NM/B 6AWG is rated at its limit to 60 C, carrying 55A. I could not find max temp ratings for outlets, but I did find specs for the outlet I have; the spec was temp at contacts < 30C rise over ambient after 50 insertions at 150% rated current, or 75A. My Audi charger is permanently mounted and was not plugged in and out at all; outlet probably has 10 cycles on it.

I am planning to take the charger to Audi; hopefully they agree I have a bad cable and they will replace it instead of saying 'performs similar to others'. But I am not willing to risk a garage fire over it, so I will most likely keep the ChargePoint; added benefit: I don't have to remember to push the timer button every time I get out of the car to charge at low rates.

Pictures attached. These were taken with a FLIR Infrared camera; I also checked the temperatures with one of those IR thermometers with a laser. Readings were similar if I placed the IR thermometer very close to the outlet; since those thermometers average across their field of view, they have to be very close to read the peak temp. From the pictures, you can see how quickly the temp gradient changes over a short distance. I took a lot more pics, but these are illustrative. When using the Etron charger, the temp at the outlet was over 60 C; with Chargepoint, about 40C, just like the plug.


Audi after 10 minutes







Audi after 20 minutes







Chargepoint after 60 minutes

moderntech18976

I had been using my Audi portable charger while I had been awaiting the arrival of my new JuiceBox Pro 40 for the last couple of weeks. As you know, the thing draws 48A on a 14-50 NEMA plug. I have to say I agree with the concern surrounding the temperature on the actual plug. After an hour of charging I can't put my hand to the head of the plug for more than a second. The charging cable from the box to the e-tron is much cooler, slightly warm to the touch but acceptable. The thing is Audi just replaced the cable while the car was in for an update. I didn't even know it was a problem, but they handed me a new one... so I don't think you have a problem with your charger (although next time you're in for service they may well replace it due to the 50%/100% issue that's been detailed on this website).

Anyhow, I installed my very sharp looking JuiceBox (BTW I installed it outside my garage, but pulled the plug inside by installing a RV cable hatch/door into the wall). It draws at 40A and it was SO MUCH BETTER! I just feel better that the plug is slightly warm to the touch and I don't have to worry about overheating, fire hazzard (eg. jerry cans, cleaning fluids, etc normally kept in garage). Plus if you have kids, they touch stuff!

For the minor bump up in charging performance when going from a 40 to 48 I don't think it's worth the worries. I don't know that running it hardwired alleviates the worry! Still a lot of energy flowing through them wires! I spent $1,000 upgrading my wiring to 6 gauge (100 feet) so I am safe according to code to draw close to 48-50A.... BUT I THINK I SLEEP BETTER with cooler running charging equipment!

FINAL VERDICT ON CHARGERS? Thanks to Amazon I actually tried and returned several chargers this summer before arriving at JuiceBox:

1) Primecom Tech - they're not ready for the big show; the 40A unit with 50 foot cable kept short circuiting and the internal circuit temperature read 149 F ! Returned item. Don't buy this for anything that pulls more than 40 A !
2) ChargePoint - really sharp looking item. After setting device to 40A I had no problems, runs very cool (temperature wise). Two "wishes" that were determinants in my decision: a) cable from box to plug was extremely short (outlet literally has to be right next to box); b) charging cable itself is about 2 feet shorter than competitors;
3) Grizzl-y - Being a Canadian I felt I had to look at this item at the suggestion of one of the forums contributors here! Really nice looking design. Apparently its claim to fame is it holds up well in harsh temperatures (the box itself for weatherproofing and assumably the cable flexibility in extremely low temperatures). When I sent product questions through the Amazon seller function, someone almost immediately returned a reply! Some might like the flexibility of changing the output amps on this device, but max is 40A;
4) JuiceBox Pro 40 with NEMA plug - came down to this or the ChargePoint. Three advantages over the CP I feel: a) longer NEMA plug cable so that while the box is installed outdoors, the plug is kept inside by installing a RV cable hatch into my garage wall; b) charging cable is a full 25 feet long; c) the WiFi app is more sophisticated and more functional than CPs. Pairing was a bit trickier than CP but once set up works great. Loads vehicle specific specs into the app so really helpful info!

My final comment about charging ..... I got my e-tron in June but soon discovered that my 3-4 year old 32A charging station was antiquated, it kept getting shorted by the e-tron trying to pull 48 A. That's what led me through a summer long trial with various chargers. My advice? Go with a national, reputable name with long history of quality product development. Don't buy from China! And no new kids on the block. I'm assuming all the new generation of devices can deal with vehicles that will try to pull more than it can deliver so you shouldn't run into short circuiting problems with the well known brands. And NEVER, NEVER buy Primetech. You'll regret it.

newmanium

Minor note - for the Chargepoint or JuiceBox plug-in version, the plug portion is supposed to be indoors. For exterior mounting, they specify to hardwire-only so the connections can be liquid-tight. Routing the plug cable indoors like you did in the garage I'd assume is satisfactory.

For longterm use, hardwiring seems like much better option no matter what as the connections can all be tightened thoroughly. I know people talk about taking it with them when they move, but as EV becomes more popular having a installed charging station in the garage will be an amenity people will want to come with the house.

ThomasW

After installing my outlet, I measured the temperature during my first charge using the Audi EVSE at various spots to make sure things are working properly. I had googled around beforehand to find some data on what temperature to expect. The limit for the components should be 185 degrees Fahrenheit which is when the plastic components start to melt. At 90C you are getting close to that limit.

In my case, both the plug and breaker were around 90 degrees Fahrenheit, everything else was significantly cooler. This was with an ambient temperature in the 60s. So I would concur with your conclusion that something is probably wrong with the plug on your EVSE, probably a bad connection between the plug and the wire.

WetEV

90 F is 32C, very reasonable.

IR thermometer is a useful tool for verification of lots of things, from electronics to wiring to air conditioning and heating to windows and doors. I first got one in the later 1990's, was very expensive. They are dirt cheap now. Yes, you may need to get very close and move the IRT around to find hot spots. Especially when you are looking for a hot 0603 component on a PCB.

Infrared camera is better, and is on my "I want one" list. Do you like the FLIR? Which model?

Bill33525

My plug shows # E152635 it gets up to about 145 degrees in the area where the blades go into the socket. Little bit less on the face of the plug.
Do I have the most recent plug version? Wonder if there is a hardwire adapter for this charger, thus eliminating the plug & socket?

Fan cooling Nema 14-50 plug. Blades of plug were 150 degrees before fan cooling after fan added temperature down near 100

WetEV

145F is 63 C, which is too hot. I'd set the cable to 50% power as well as the fan, and tell Audi they got a problem.

Bill33525

Thanks for the tip. Had intended to "text" my service advisor.

WetEV

Might a good idea to start there. Several of the updates have involved the charging cable. I don't know if any of the updates replaced a part, might have.