It plugs into AC outlet, but it also has built-in battery to keep it powered for over an hour i believe.
I thought battery powered ZB devices are generally considered end point devices with no repeating feature to save on battery power. But with this device that doesn't seem to be the case.
I used Zigbee Routing Map App and was surprised to see that this device is actually identified as a repeater or router!
So it is actually a mains powered device with a battery backup then? Which makes sense for a siren, so you can still get alerts if power goes out during some sort of emergency situation.
When it goes to battery power since it is not expected to run on that battery for an extended time it probably does not go into "battery" mode where it trying to save power, so it is still functioning as if it were plugged in.
If the device continues to act as a repeater while unplugged, the battery will probably die fairly quickly, leaving you with a potentially broken zigbee mesh.
Mark's correct -- you don't want a battery device routing on a regular basis; it would chew through its battery pretty quickly.
Mains-powered devices that have a battery backup are intended for short-term emergency use (e.g. keeping a siren available during a hopefully brief power outage) or as a way to get things gracefully shutdown (when combined with a hub UPS).
I use several Zooz ZAC38s in my setup... Sure, if their respective circuit goes down, they'll continue routing too, but I don't really care about that. My smart home setup isn't about security per se, so if some/all power is out, I don't need my entire system to stay up & running.
What I do care about is the ability to get my system gracefully shutdown during the outage to avoid database corruption... The Z38s tell me what circuits are out (one, some, all), and since the hub's UPS gives me several hours, that gives me time to determine the severity of the outage and then I can decide to either ride the outage out or get the hub properly shut down.
I suggest using a driver by @kkossev to monitor the connectivity of the Tuya USB Repeater (health status in the driver). I have about 6 of these and from time to time they drop off the mesh.
This is perfectly fine for me though coz even when unplugged the battery seem to have lasted hours (when testing) and that's enough for backup.. the important thing is that wherever I put a siren (which is spread out evenly) I know that i am in fact extending my mesh network... and when there's a power outage, i know my repeaters will remain up for a few hours! 2 birds with 1 stone!
because most zigbee meshes i've seen rely on ac powered devices (ie. light switches and plugs and outlets) to repeat signals. The whole network breaks down during power outage.
So this is especially good if one is using the system for burglar / emergency alarm.
The hub can be backed up by UPS
The sensors (door, motion, smoke) are all battery powered
The sirens AND REPEATERS are also backed up by batts (hours worth)
