Totally useless battery status?

I’ve a STH-ETH-200 hub and a couple of multipurpose sensors being used on doors for around a year, all of which never showed less than 100% battery…I guess that’s fishy to begin with but I just thought hey maybe they are really long lasting…

Then today one sensor on a door started to trigger false alarms, open and then close events happening in the same minute every couple of hours. I took the battery out and tested it showing very little juice left. I swapped in a battery from a working sensor but still wasn’t able to get it to reconnect. Then I found out the same thing happened on another door sensor, except no false alarm.

I’m going to buy fresh batteries, but it’s ridiculous that the hub is not able to keep track of battery level even in the ball park, and there doesn’t appear to be any built-in alerts for low sensor battery (have to purchase from 3rd party).

  1. It’s not the “Hub” which tracks battery levels. Each sensor reports it’s battery level (based on voltage) at a configurable interval.

  2. Unfortunately, batteries don’t follow a linear drain curve; but normally the battery of most Things lasts long enough to report a few drops (e.g. 88%, 77%, 50%, 1%). I’ve run sensors on 1% for weeks.

  3. Low battery alerts are built into the SmartThings App.

  4. I’m not certain, but you may need to have “Device Health” option in the App enabled to receive these.

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@tgauchat: Appreciate the reply. I’ve always had Device Health enabled. Is it odd then that after a year of use I never got any warning?

A battery tester showed the batteries to have very little juice left. When installed in the sensors, one of them will throw periodic false alerts and another just permanently reports “closed” no matter how the door is moving. Both sensors still showed the dying batteries as 100%.

What brand of sensors?

Certainly could be a bug or characteristic of the particular brand/model…

What about other sensors you have?

Both are Samsung multipurpose sensors that came in a bundle with the V2 hub. I bought 4 more since but those obviously haven’t been in use as long. The motion sensor that came in the bundle having been in use for same amount of time still works but also shows 100% battery.

Here are the Battery Levels of most of my Sensors.

They are mostly Centralite (PEQ branded) … i.e., SmartThings “V2” sensors; not the latest, but not the originals either… except for “Sense Back Door” is an original SmartThings multi. That one uses 2xAAAA batteries (last perhaps 3 months?), shows 1%, but is still fully functional. The other 1%-ers … probably dead.

Notice the variety of battery levels, though.

(This image brought to you courtesy of ActionTiles :slight_smile:).


The “French Window” and “Den Door to Garage” (both showing 44% Battery values as their last report); are not currently functional. They died sometime between 44% and 0% without sending a final Battery report.

Also note that the “Den Door to Garage” (contact sensor) is almost always left open. So it’s battery drained solely from reporting Temperature and Battery status periodically. That’s too bad; but a custom ZigBee config could be sent to reduce this reporting interval, I think. The SmartThings DTH doesn’t offer any such “preferences”.

It is therefore a shame, that SmartThings App doesn’t consider 44% to be a “low battery alert” threshold as a built-in feature. But it’s pretty easy to use a custom SmartApp for this (or one of a few Community ones).

The 100% status has been a problem since September. There is a fix that has been working for me and sumbitted for change with a Githib pull request that has gone no where since October. If you dont mind them running in the cloud with a custom DTH, there is a fix to get battery reporting on the Centralite models back.

ST Multi-Sensor battery reporting issues.

There are free smartapps that can monitor battery life for your devices too.

Of course that assumes the devices are reporting their battery status correctly. You have apparently run into the known bug with ST multipurpose sensors that popped up earlier this year I believe.

And as @tgauchat mentioned, disposable lithium and alkaline batteries (the kind that power devices connected to your ST hub) do not discharge the same way as rechargeable lithium batteries in phones/tablets/laptops. So even under the best of circumstances, you will never get the kind of battery reporting that you have become accustomed to. Blame physics, I guess :man_shrugging:

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The battery percentage provided in SmartThings appears to be a weighted value based upon the voltage value sent by the device, and the minimum voltage needed for the device to properly function. So a battery producing 2.6 volts in one device may show 60%, and that same battery in another device by another manufacturer may show 90%.

In my opinion all battery percentages are useless.

Here’s why:

  • Devices measure the wrong voltage value, and the readings may vary considerably from a volt meter reading
  • Percentage calculations and weighing methods appear to be arbitrary and vary from device to device.

What’s needed

  • Actual voltage measurements versus a perecentage
  • The ability to adjust the voltage reading as is done for temperature
  • A clear statement of the minimum voltage needed for normal device operation

Check out this thread for more information

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Definitely don’t hold your breath waiting for this to happen.

Have you looked at both ZigBee and Z-Wave DTHs? Does the DTH do the battery % conversion you describe? I doubt it… Doesn’t the hardware (firmware) directly report battery level as a % rather than voltage???

The first few DTHs I reviewed were Zigbee, then I looked at two Z-wave DTHs before responding. I’m not a zigbee or zwave hardware or command expert, but I can generally read and understand the DTH code.

Zigbee appears to send a voltage value that is massaged into a percent value by the DTH. Z-Wave appears to send a percentage value, that is directly reported. I’ve also noticed a Zigbee low voltage warning that seems to be produced by all Zigbee battery powered devices. I’m uncertain if that information is processed in Smartthings.

Hopefully a DTH guru will notice this thread and help with some insight.