What am I missing....

[Not Sam]

Thanks everyone for the advice and insight. I put a clamp-on ammeter / power meter at the circuit breaker as @DeaneG suggested and it showed 60-62A, true RMS power of ~14.5 kW, and 235V (down from 236V at ambient). Apparently EVSEs typically have Power Factor Correction built in, so a PF of 1 is expected here.

So both the voltage and the amperage were lower than nominal.

Edit: As @Alex points out below, the power factor correction is done by the charger in the car, not by the EVSE.

 

[DeaneG]

Thanks everyone for the advice and insight. I put a clamp-on ammeter / power meter at the circuit breaker as @DeaneG suggested and it showed 60-62A, true RMS power of ~14.5 kW, and 235V (down from 236V at ambient). Apparently EVSEs typically have Power Factor Correction built in, so a PF of 1 is expected here.

So both the voltage and the amperage were lower than nominal.

I've watched charging voltage drop by about five volts at my Model 3 as the current ramps up from 0A to 48A. I think this is pretty much expected through the breaker and a 50' run of the standard wire gauge for a given ampacity. I used a 120V outlet on another circuit as a Kelvin contact to the panel's bus, and found that most of the drop was indeed in the breaker and wire run.

 

[Not Sam]

I've watched charging voltage drop by about five volts at my Model 3 as the current ramps up from 0A to 48A. I think this is pretty much expected through the breaker and a 50' run of the standard wire gauge for a given ampacity. I used a 120V outlet on another circuit as a Kelvin contact to the panel's bus, and found that most of the drop was indeed in the breaker and wire run.

In my case, at least at the breaker, voltage only dropped about 1V (from 236V to 235V) when charging from 0 - 60A. Don't know what it is at the EVSE, no easy way to measure it there. There's about a 30ft run to a J-Box adjacent to the EVSE, but they ran oversized cables there, and properly sized cables for the last 2ft to the EVSE. Then of course there's the 25ft of EVSE cable.

 

[Alex]

Apparently EVSEs typically have Power Factor Correction built in, so a PF of 1 is expected here

The EVSEs are just a glorified switch with a handshaking signal. The power line is effectively connected to your car. It's highly unlikely they do any active power factor correction. If anything is doing any power factor correction it's the car's charger.

 

[Not Sam]

I claim no expertise, but I read this on the Internet so it must be true :

"High-power devices like EV chargers – whether a compact onboard type rated for 3 kW or a CHAdeMO 100 kW monster – invariably use a boost converter (see Fig. 5) to perform active PFC."

A closer look at power factor correction - Charged EVs

Power Factor Correction (PFC) used to be something that electronics manufacturers only grudgingly added to a product – usually because of complaints about breakers tripping prematurely, or to meet regulatory requirements in the EU – but these days PFC is showing up in more and more products...

chargedevs.com

 

[Not Sam]

I claim no expertise, but I read this on the Internet so it must be true :

"High-power devices like EV chargers – whether a compact onboard type rated for 3 kW or a CHAdeMO 100 kW monster – invariably use a boost converter (see Fig. 5) to perform active PFC."

A closer look at power factor correction - Charged EVs

Power Factor Correction (PFC) used to be something that electronics manufacturers only grudgingly added to a product – usually because of complaints about breakers tripping prematurely, or to meet regulatory requirements in the EU – but these days PFC is showing up in more and more products...

chargedevs.com

which is about the charger, not the EVSE, I realize now

 

[Alex]

I claim no expertise, but I read this on the Internet so it must be true :

"High-power devices like EV chargers – whether a compact onboard type rated for 3 kW or a CHAdeMO 100 kW monster – invariably use a boost converter (see Fig. 5) to perform active PFC."

A closer look at power factor correction - Charged EVs

Power Factor Correction (PFC) used to be something that electronics manufacturers only grudgingly added to a product – usually because of complaints about breakers tripping prematurely, or to meet regulatory requirements in the EU – but these days PFC is showing up in more and more products...

chargedevs.com

Yes, these are onboard chargers for 3kW. EVSE is just a wall connector switch. The CHAdeMO 100kW charger is a DC charger.

 

[Not Sam]

Yeah, sorry, I managed to misread both your post and the article I quoted.