OpenEVSE charge regulation – A possible improvement?

[pb66 (Paul)]

@BrianD

I would like to simplify the problem by starting with MartinR removed. During any testing I shall simply switch him OFF.

I hope to achieve the goal of regulating the power flow to the EV based on the simple rule of:

EV = PV – H2

Where EV is power diverted to the car via OpenEVSE

PV is power from solar

H2 is power to Henley block 2 as measured by CT4

This part would have worked fine with the original Henley block arrangement as it was so that H2 doesn’t include EV because to expand your equation above it would become

EV = PV – (House CU + EV)

when in actual fact it should be

EV = PV – House CU

As the HB’s were (EV on HB1), then yes CT4 can be used directly to ascertain the available power for EV charging which is what I’ve been saying,

Originally 8 days ago on the other thread

@pb66

I think you need to create a “available_excess” feed which is pretty much PV minus regular non-diverter consumption.

. . . and in this thread 3 days ago

@pb66

You simply need to subtract your normal consumption from the PV and use that “available PV” value to drive your EV charger

Alternatively you could move CT4 to between HB2 and the house CU or maybe some form of feedback value could be used, for example available for EV = PV – (HB2 - used by EV). Whether the EV is removed from the “normal use” by changing the wiring, moving the CT or in the maths, EV must be removed from the basic PV - USE equation.

Otherwise when there is 2KW of spare PV the EV will be told to use 2kW at which point there is no spare PV so the EV will be switched off and then the 2kW spare reappears so the EV is told to use the 2kW etc etc etc

Do you agree with this part before we reintroduce the diverter?

[edit] Looking closer at the diagrams, moving the CT not the wiring seems the easy choice, the change of diagram style confuses comparison between what you had originally and what you have now.