We use a number of Strompi in combination with another UPS that we are phasing out. For now we need code to be compatible to both options so we need to detect if a strompi is present on the pi(3).
Is there a way to detect this on a pi without communicating through serial (not requesting a status as some kind of ping)?
you could use the StromPi 3 in serialless mode. Once you configured the StromPi 3 there is no further need for communication via serial. The StromPi 3 uses then a digital pin of his STM32 controller for showing the actual power status. If the primary power source is working this pin is in high state. If the primary power source fails this pin is set low.
Technically you can use this signal to check if a StromPi 3 is present.
If you have further questions don’t hesitate to ask.