question

I see what you mean. You almost want to spoof absorption/float mode without being at 100% SoC (VIctron EV charger might be a cleaner way to go but pricey)

You've set DVCC charge limit to 0, is DC coupled PV feed in excess also enabled in ESS also? If it is and it's not working then see hacky solution below if not enabling it might solve it:

It's a bit of a hacky way around it but maybe using node red and grid set point?

Needs to be a dynamic calculations so node red might be ideal This is far from a clean solution though but best i can think of. (Personally wouldnt set this up in a customers house unless they were heavily involved and understood what was happening/could disable it if they needed to)

I've also assumed no grid export limt:

When customer enables this "mode" (unsure how you're doing that but maybe a shelly switch or some other http api switch)

When switch is on node red will do the below flows:

Get the amount of power it can export by the below calc:

Total power output of all solar MPPTs + AC coupled PV if exists - AC Loads - a small buffer

Small buffer is to cover losses of converting PV power output to AC and any others in the system (this will be trial and error to determine the number)

Then whatever that number is you use node red to set the grid set point equals to the negative of that number.

For example: Node red would get the below values and do the below if statement:

PV incoming 10,000w

AC Load 500w

if PV - AC loads > 0 then

set grid set point -9500w (less the fixed buffer amount)

else

set grid set point 0w

Node red will constantly loop this flow and adjust the grid setpoint. Then if sun goes down AC loads > PV coming in grid set point will be 0 and system will behave normaly. However the customer would need to remember (or schedule via shelly smart switch) to turn this feature off as it will essentially prevent batteries from charging by exporting it all instead (the main limitation without communication between victron

I'm unfamiliar with zappy but if there is an API you could get node red to also check if it's taking power in ie cars connected and not full. If it's fully then you could have node red not run the above flow as you'd be pointlessly exporting grid power if cars already full/not there.

Way more automations could be added but again experimental maybe not ideal for a customer who's not tech savy/just wants a flawless system.

Thanks that might be an option, slightly concerned about the reaction time, it always seems to take a few seconds to react to a setpoint. This might be a problem if solar production is up and down.

However, I might have just worked out a way with the new option (V3.0) in ESS Scheduled charging.

Set a Schedule Charge for all day with a low target SOC and the new "Self-consumption above limit" set to PV. This prevents Charging and then set a high -ve setpoint and this seems to send all solar to grid. I've yet to test it fully for any quirks or side effects but my initial tests it seems to do the job.

I have another charging solution for my EVs, so I don't know what the Zäppi can actually do.

The Use-Case you describe is to use PV access power for charging, only.

...and, when doing so, you probably/most likely don't want to have the stationary/house battery discharging while the EV is charged from PV.

The best solution would be

• to set the allowed grid-setpoint to the value of the available PV access power (positive value)
• instruct the EV Charger to only use that amount of power, hence the resulting grid-power will be 0, when charging the EV.
  Typically an EV charger will control this via the allowed current offered to the EV over the Type2/Mode3 CP connection - so depending on the number of phases the EV will charge from, you will need to calculate that allowed current from the access PV power available .. note that charging will only starts from 6A current (per phase), as per technical standard.
• Best would be, if the charger will monitor the power that is going into the EV, so you can dynamically adjust, when the car battery is reaching full state or when the car BMS performs a balancing of its battery during charge.

Other ways of doing this are documented on myenergi zappi web pages and fora e.g. this and this. Basically you need to locate the CT for the zappi where it thinks it is measuring the export, whereas the the Victron setup needs to detect the zappi as a load not an export.

Edited to fix broken link and add:

Normally in eco+ mode the zappi will then use only power that would otherwise be exported.

However if you set the zappi to fast mode it will ignore its export measurement and draw the current it wants and the Victron will see this load and prioritise this over charging the battery.