I am running ESPHOME with slipx06 Sunsynk yaml on an esp32c-3. Currently I power the esp32-c3 from an external power supply, but I would like to get rid of this and power the esp directly from the inverter. sgs mentioned that the rapid shutdown (RSD) port can supply 12V. I checked this on my inverter and it indeed has 11.8V between connection 11 & 12. Does anyone know what the current rating of this port is?

SUNSYNK-8K-SG01LP1

52 minutes ago, ccrause said:

I am running ESPHOME with slipx06 Sunsynk yaml on an esp32c-3. Currently I power the esp32-c3 from an external power supply, but I would like to get rid of this and power the esp directly from the inverter. sgs mentioned that the rapid shutdown (RSD) port can supply 12V. I checked this on my inverter and it indeed has 11.8V between connection 11 & 12. Does anyone know what the current rating of this port is?

SUNSYNK-8K-SG01LP1

The 9 pin RS-232 port where the Solarman stick logger or Sunsynk logger plugs into, gives 12 V.

Pin 5 = 0 V (GND) and pin 9 = +12 V.

The power rating on the dongle is 4W, so it should be good for 330 mA max.

Edit: I thought that the ESP32‑C3 runs on 3.3 V? Are you going to use a buck converter? In anycase, the current draw of the ESP32-C3 is 1.7-2W so it is within spec.

Edited July 26Jul 26 by Yellow Measure
added amps

@Yellow Measure : Yes, I will use a buck converter to step down the voltage to 5V (the RS485 module is running at 5V).

I am also running the Sunsynk dongle, so the 12V supply will have to power 2x ESPs. If the dongle is rated at 4W it implies it is using a linear regulator (12V * 0.33A). Using a buck converter (12V -> 5V) at 80% efficiency would then add another 2W to this. It doesn't sound like much, but I do not want to blow something on the inverter side.

16 minutes ago, ccrause said:

@Yellow Measure : Yes, I will use a buck converter to step down the voltage to 5V (the RS485 module is running at 5V).

I am also running the Sunsynk dongle, so the 12V supply will have to power 2x ESPs. If the dongle is rated at 4W it implies it is using a linear regulator (12V * 0.33A). Using a buck converter (12V -> 5V) at 80% efficiency would then add another 2W to this. It doesn't sound like much, but I do not want to blow something on the inverter side.

Looking at my own spare Solarman dongle to double check: It states

Model: LSW-3

Input: DC 5V - 15V 1.5W

It may be best to stick with the RSD port. Or incorporate a small 1-1.5A 12V PSU on the UPS load side, more extensible solution, because you can use it to drive some PC cooling fans as well.

8 minutes ago, Yellow Measure said:

It may be best to stick with the RSD port.

Thinking/speculating a bit more about the on-board power supply, there is probably a single power supply connected to the DC bus that powers all the electronics - so there is probably some fat in the 12V supply.

8 minutes ago, Yellow Measure said:

Or incorporate a small 1-1.5A 12V PSU on the UPS load side, more extensible solution, because you can use it to drive some PC cooling fans as well.

This is a good suggestion, will check to see how easy it is to make a connection inside the enclosure.

Thank you for your input!