Low Battery

Low Battery

Every battery that Device Sentinel finds is watched automatically. New devices with batteries are picked up the moment they appear in your registry; there is nothing to register or manually configure when adding a new device or sensor.

This screen allows you to define what counts as a low battery and configure exclusions for devices whose battery levels you do not want reported.

Discovery and Election

Each device gets one battery entity. When a device reports both a percentage battery and a binary low-battery flag, the percentage is used because it tells the integration how low the battery is, rather than it just being low.

Battery is judged at the device level and not by the specific entity. This means the judged entity can change over a device's life, which is why there is no per-entity exclude list on this screen: a device-level exclusion cannot be bypassed just because the underlying entity changed.

How a Battery Is Judged

A battery is flagged when its level is at or below your defined threshold.

• The threshold: The default is 20 percent, set on this screen. Any device battery reporting at or below the set value will be reported as low.
• Persistence: The moment a battery crosses the threshold, its timestamp is saved. It is retained across restarts, so a battery that has been low since Tuesday reports so.

The Second Question: Which Batteries Are Decaying Rapidly

The threshold answers which cells are low. It cannot answer which are about to be.

One morning a soil sensor read 82 percent and a door sensor 24 percent. The percentages say the soil sensor is healthier. By that evening, the soil sensor battery was empty and the door sensor was still reporting 24 percent.

Days Till Empty is the setting for that, and it sits on this screen beside the threshold. A cell projected to reach empty inside this setting is flagged, so it becomes a line in the problem list, your daily brief and your phone the same way a low battery does. The range is 7 to 30 days, defaulting to 30.

A flagged cell reads "empty in about 2 weeks". It says the time in words rather than a count of days on purpose, because the projection moves as the cell reports; The Battery Report explains why and shows the whole picture.

A cell that is not moving is never flagged here, so a healthy fleet stays quiet. And a cell already below the threshold is not flagged twice: when both apply, one item reads "battery 16%, empty in about 2 weeks".

Where It Is Visible

You will see low batteries on the problem list (for example, "Soil Irrigation: battery 0%"), where they can be acknowledged to silence notifications. They also appear in your daily brief and the device telemetry file, described in The Diagnostic Reports. The telemetry file records raw battery levels day by day, so a cell's drain over the past couple of weeks is visible.

The Excludes

Excluding a battery on this screen stops battery reports for that device only. Everything else about the device, like whether it has frozen or fallen offline, stays watched. If you want to drop a device from all reporting entirely, use the Global Exclusions screen instead.

There are three exclusion lists, running from broad to narrow. They interact exactly like the global lists: if you exclude at a higher level and save, everything it covers disappears from the narrower lists below. Remember the dropped-not-parked rule: if you later undo a broad exclusion, you will need to re-pick any narrow items you still want excluded.