Hello,
I have a problem with my Shelly Pro 4. I don't have another to compare it with.
The problem is when switching an external relay. It frequently causes the Pro 4 PM to crash. Sometimes it reboots. Sometimes it just shows a solid white display, and doesn't reboot.
I've tried a snubber connected either at the Shelly end, or at the external relay end. It makes little, if any, difference. [Edit - Please see the 13th post in this thread for an update, and more clarity - what I thought was a snubber is actually a MOV]
I need to install this unit tomorrow. But it needs to be reliable. I've been very impressed with the reliability of Shelly devices, but this unit isn't good.
One thing that occurs to me - could it be caused by the back emf spikes propagating via the power measurement circuitry across the shunt resistors? If so, I would be happy to cut these tracks - I'm only driving relays, so the power measurement is irrelevant.
Thank you for reading. I really hope someone has a solution!