Device Behavior After Power Outage?

What happens with the sensors? Do you get a false positive?
I’m traveling and i will install a powerful siren controlled by a z-wave switch and triggered by a motion sensor.
In my neighborhood,Power Outage is normal once or twice a month, so i don’t want to trigger the alarm just because the power outage while i’m away.

Based on your experience, after a power outage;
How does the motion sensor behave? How does the light switches behave? Or any other smart device

The motion sensor should be fine. Most of these are battery-operated anyway.

As for the siren, it may depend on the exact brand and model.

Typically the switches after a power outage are in the “off” state and the smart bulbs after a power outage are in the “on” state, but there is some variation between specific models.


This is the siren
Hobbypower AC 220V Mini Motor Driven Air Raid Siren Horn For Car Truck Alarm MS-190

The motion sensor
Monoprice Z-Wave Plus PIR Motion Detector with Temperature Sensor

The zwave switch
Aeon Labs DSC18103-ZWUS,White,US,AL001 Aeotec Z-Wave Micro Smart Energy Switch, 2nd Edition

I could wake my entire neighborhood up with this. It would be terrifying. They also sell a 125db model. Ha.

Not true, unless you didn’t put batteries in the SmartThings hub. That’s why it has batteries. It will run for about ten hours just on battery, and during that time it will continue to receive notifications from the battery powered sensors.

Of course, if you still have the old V one hub, it didn’t have batteries, so it goes down when the power goes out.

[quote="[deleted], post:7, topic:67776, full:true"]
Are you sure? I have the V2 hub and it definitely misses ST Multi events during power down (gets stuck in the opposite state till next event occurs).

Just did another test to be certain and this is what happens for me.

Maybe my batteries are dead then… Will check!

As long as you using a device type handler which is eligible to run locally, then yes, I’m sure.

Of course, what the hub does with the sensor report is a different question. But if you have a smart lighting automation which does nothing except turn on a locally eligible light switch when the locally eligible sensor reports to the hub then, yes, that should continue to work during a power outage.

The app is going to get out of sync with the actual device states if there is a power outage. This is because the hub cannot talk to the mobile app except through the cloud. There’s no way around that at the present time.

I think, but I’m not 100% sure, that if after Power and Internet are restored you then took the hub off power all together (including taking out the batteries) and left it off for about 15 minutes and then put it back on power that it will re-sync with the cloud which should then update the app. Which might be easier than going around the house and re-triggering every sensor you have.

Something is definitely wrong. I would talk to support. There are lots of people using sensors and switches via SmartLighting when the hub is on battery power.

I thought the local processing will still work only if you lost Internet. The battery is just for easy pairing of new devices and won’t do any automation with just battery. I would also like to know about this. I have the same test result as @anon36505037.

Wow, interesting. I believe you, but then what the heck is the point of the batteries?

@slagle is it true that if the hub switches to battery power it won’t process zwave or zigbee traffic anymore?

so basically during a power outage, nothing works,
even if your sensors, alarm and ST are using batteries. You need internet or main power

but when the main power is back… what happens? did you test that? @anon36505037

Not the case. It will do ZigBee and Z-Wave but only devices that are eligible for local execution. If you are seeing something different please contact support.

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is there a list for the devices that are eligible for local execution?

Just to be a little more clear so I can test it again later. Are you saying local processing will still be working with no Internet and only batteries to the hub?

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Yes :slight_smile:

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