AJH wrote:

In the absence of a power supply problem would the ev charging be at a
constant rate

the EVSE* will tell the car how much it is allowed to take, this may be
a fixed setting, or it may vary depending on consumption elsewhere in
the house and/or your own solar generation.

or does the battery* dictate what power it can absorb and
turn it down?

The in-car charger will determine how much it wants to take, dependant
on how much it is allowed and things like battery temperature.



* the box on the wall that most people refer to as a 'charger' isn't
really, it's just a glorified relay and a bit of signalling