Clarity drawing more than normal Amps

[clarityowner12]

I plugged in my Clarity and went inside, Came back out and heard a “hissing/electric noise” (I have a video I can upload if someone wants to hear it)

What I noticed was on my L2 charger, I normally draw around 29.5A, when I checked it it was reading 37A!!!! I’m curious if it has happened to anyone else and get any insight because it’s my understanding that the car tells the charger what it needs and or would limit current based on what the charger in the car needs... any thoughts?

One last thing, I immediately pulled the plug and waited 5 minutes and reinserted and have charged 10 times since and the problem has not duplicated

 

[lordsutch]

I think technically both had an issue - the EVSE and car negotiated a max charge of 32 amps, so the charger shouldn't have supplied more than 32 amps and the car shouldn't have drawn more than 32 amps. Ultimately I think the EVSE should have cut off if it was drawing more power than it was designed to handle to protect its wiring, however.

 

[The Gadgeteer]

Is your ESVE a 40 Amp or more unit?

Odd that a rate greater than 32 Amp was negotiated.

 

[JCA]

I'd actually suspect the charger's measurement circuitry before the car's. The charger itself is generally pretty simple -- the high voltage part of the EVSE (charger) is just a relay on the 240V line between the wall and the car; there's no special filtering or transforming being done there. The control circuitry is a low voltage handshake where the EVSE "advertises" how much current is available via the frequency of a wire going to the car. The car puts resistance on that wire to tell the EVSE when it's connected and ready to charge, at which point the EVSE turns on the relay. The car limits its charging draw rate to the advertised value.

Even if the EVSE falsely advertised more than 32A or the car thought it did, the car's equipment maxes out at 7.2kW (30A) so there'd have to be something really badly wrong with the car side to exceed that.

The display on the EVSE is most likely just a current sensing coil around one of the wires going to the car, connected to some cheap electronics. It's much more likely that coil or electronics is bad than that the carefully engineered equipment in the car, but anything's possible. Could you tell if the noise was coming from the car or the EVSE? I could see a loose coil or wire in the EVSE resulting in both noise and a false reading.

But having the dealer check out the car next time you're there wouldn't hurt (well, assuming the service department has any idea how to test the car's charging equipment!)