Thanks to the magical powers of the SonoffLAN integration, TRVZB devices appear in Home Assistant. Each one comes with its own shiny little card, and on that card - surprise! - we get two mysterious entities: Limit Voltage and Run Voltage.
According to the creator of SonoffLAN (who presumably has access to the secrets of the eWeLink cloud), these values are pulled straight from said cloud. So far, so good.
Except… Limit Voltage always shows “Unknown.” Always. As in, it’s consistently, reliably, proudly useless. Meanwhile, Run Voltage is a bit more adventurous, sometimes it’s 12V, sometimes 20V, and sometimes it just stares back at you like it’s daring you to make sense of it.
So what are these entities? What do they do? Why are they here? No one seems to know. Maybe they’re voltage-themed performance art. Maybe they’re just here to pad the entity count and make your dashboard look more impressive. At this point, their usefulness is roughly on par with giving a microwave to a cat. Sure, it’s technically a device, but good luck getting any meaningful interaction out of it.
If anyone has cracked the mystery, please share. Otherwise, I’ll just keep admiring my Unknown Voltage like it’s a modern art installation.