Virtual CT Meter / Grid Power input via MQTT for zero-export control?

[SamLue]

Hi,

I have a SML optical reader on my grid meter connected via ESPHome, which publishes current grid consumption (in Watts) to MQTT every second.

My goal is to feed this grid power value into the B2500-D so it can regulate its output accordingly — ideally without implementing my own control loop.

The B2500-D supports an external CT clamp / smart meter for automatic zero-export control. My question is: Is there a way to feed the current grid consumption value via MQTT so that the device handles the regulation internally?

I looked through the available MQTT topics but couldn't find anything that maps to an external meter input. Specifically I was looking for something like a p1_meter_power or grid_power topic under set/.

If this is not supported yet, would it be feasible to add? The SML value is already available on MQTT, so the only missing piece is a way to pass it to the device as a virtual CT meter reading.

My setup:

• Device: Marstek B2500-D Type: HMJ-2 Firmware Version: 110.9
• SML reader: ESPHome with optical head on Ferraris/digital grid meter
• Broker: Mosquitto

Thanks in advance!

[thowiegit]

not via mqtt, but there is another solution for your need from tomquist: https://github.com/tomquist/b2500-meter

[SamLue]

@tomquist is a brilliant guy! Thanks a lot