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I have purchased several OpenEVSE stations over the years, but today I am referring to my first, Order #4254 06Aug2017 "Model P50A "Advanced" - 40A Charging Station Powered by OpenEVSE".

I use this one with a 2014 Toyota RAV4 EV, which can draw 40A.  I have the EVSE configured for 40A max (240v) on a 50A supply circuit, with a ~20' run from the EVSE to the breakers panel.

I normally plug in when I arrive home, the vehicle has a timer set such that it calculates when to begin charging so that the vehicle is fully charged when I am about to depart the next day.  So, I'm normally handling a "cold" nozzle.  Today, I had occasion to need to charge during the day, so I set the vehicle to "charge immediately" and plugged in.  I was starting from around a 50% SOC.  I unplugged at around 85% SOC because I needed to move the vehicle.  Immediately, I noticed that "hot electrical/hot plastic" smell we come to recognize.  I found my cheap Raytec IR thermometer and was able to obtain a momentary reading of 200°F !  To me, that is a hair-raising temperature for an electrical connector.  By the time I got my phone camera ready to document, the highest reading I could obtain on the J-Plug was 189°F (see pics).

I see no discoloration/corrosion or melted bits on either the J-Plug or the vehicle's inlet nozzle.

What is a normal temperature for the J-Plug that's been run about 1.5 hours in 50°F ambient?  Should I replace this J-Plug?

Pictures are both attached, and links below:

http://asavage.dyndns.org/Toyota/RAV4/EV/Owners_Rigs/Al's_2014_blue/Inlet_Nozzle/IMG_2295.jpg

http://asavage.dyndns.org/Toyota/RAV4/EV/Owners_Rigs/Al's_2014_blue/Inlet_Nozzle/IMG_2298.jpg

http://asavage.dyndns.org/Toyota/RAV4/EV/Owners_Rigs/Al's_2014_blue/Inlet_Nozzle/IMG_2299.jpg

http://asavage.dyndns.org/Toyota/RAV4/EV/Owners_Rigs/Al's_2014_blue/Inlet_Nozzle/IMG_2300.jpg

Unless you are an expert, never solder high-current conductors.  Crimps can be QC'd, solder connections can't, and there are so many ways to solder large conductors and large cross-section wires incorrectly that chances are much higher of a soldered connection failure than a mechanical crimp failure.

I've probably soldered tens of thousands of connectors & joints, but I'd never solder, say, house wiring, even though that was the standard -- 100 years ago!  Mechanical connections for high-current joints are the standard not because it's cheaper but because it's more reliable.

It's just too easy to under-heat or over-heat a large conductor.  You don't want solder wicking up the wire, either, only into the connector, and that's difficult to control.

This is a failed crimp (I believe) but I'd never suggest it wouldn't have failed if it had been soldered.

Oof. This is one reason why I like soldered connections.

I've replaced the nozzle and cable with new.  The crimp connection of one of the high-current leads' sockets to the twin 12ga wires had failed:

I'm disappointed to see this, as the use was light (nightly charging at home of one vehicle, generally five days/week).

There is evidence of corrosion to some of the screws in the nozzle.  I'm surprised non-corrosive fasteners (eg stainless steel) weren't used.  I'm near Seattle, everything is wet most of the year, it's not reasonable to expect a nozzle to only be used in a dry environment.

I'm glad I was able to detect this failure prior to damaging the inlet socket on the vehicle.

I am aware of those nozzle failures of Schneider and Blink charging stations from a decade ago.  Note that the failures were not of the charging inlet/socket, but of the nozzles containing the female/spring contacts.

I have ordered a replacement nozzle & cable from the the OpenEVSE store (order #9011), SAE J1772 Type 1 - EV Cable 25 (48A) and will replace the nozzle and associated cable.