What kind of variable load does an EV car present to the EVSE?

[fcb]

Is there a way to query the car's existing energy state (how full the 'tank' is) ?.

Also, do most EVSE & most cars use the digital protocol? I guess it's "analog alone" or "analog & digital" (but never just digital), analog being the fall-back.

Nope.

AC. All EV's with the exception possibly of Tesla, are solely 'analog' as far as I'm aware. So no SOC from the vehicle. As Mike said, you could detect the taper-off, but this will vary depending on how the vehicle is setup, temperature, initial  SOC, etc...

There is a PLC (power line comms) protocol for V2G though, but largely irrelvant as no car has production V2G as far as I'm aware.

If you want to tap into OLEV grants then their are a whole heap of other things you should do - OLEV distorts the market..

[DBecker]

What kind of frequency content & phase shifts does the current draw from an EV car have?

For the purposes of power calculation is some kind of DSP indicated, or does the car's charge current stay pretty constant (slowly smoothly varying)?

I'd like to make a semi-realistic LTSpice model of what one might realistically see during the charge process on an EV car.

There are a wide range of chargers.  There are few general statements that you can make.
At this power level you can expect that the in-vehicle chargers are high quality with good power factor correction and filtering.  Even the conversion market from a decade ago had reasonably good designs.

Are you planning to calculate real and apparent power in your EVSE "by hand"?  Rather than using a proven solution such as a CS5463?  You are going to need quite a bit more in-depth expertise than you'll get from a few questions on a message forum.

Charge strategy varies.  No EV charges to 100% capacity, or even 100% of nominal capacity.  They typically terminate far enough away from fully charged that the battery charge acceptance rate is easily above the EVSE Level 2 maximum.  So it wouldn't be unusual for charging to end with no taper down.

[NiHaoMike]

Many (if not most) modern EVs have networking, is there a standard way to query the current charge level?

[mikeselectricstuff]

Many (if not most) modern EVs have networking, is there a standard way to query the current charge level?

Pretty sure each manufacturer does their own thing

[741]

You are going to need quite a bit more in-depth expertise than you'll get from a few questions on a message forum.

Do you mean things like DSP?