Aqara Presence Sensor FP2: Battery Draining Faster Than It Should
Battery Draining Faster Than It Should on the Aqara Presence Sensor FP2: what we found on our own £74 unit, the checks that resolve it, and when it is a warranty case rather than a setting. A device t...
Maya Okonkwo
The symptom
Aqara Presence Sensor FP2, power USB-C. Battery Draining Faster Than It Should is the fault being chased here, on a unit bought and tested rather than loaned. It is genuinely good at zone mapping so one sensor covers several areas, and the thing that repeatedly cost it marks was needs mains power.
A device that comfortably lasted a day starts needing a top-up by mid-afternoon, usually within a few weeks of an update. That is the behaviour; what follows is how it tends to present on this particular Aqara, and what to rule out first.
Worth knowing: Work through these in order. The first two resolve the majority of cases and neither risks your data.
Start here
| Check | Why it matters |
|---|---|
| Is it reproducible? | If it happens once and never again, log the time and move on — chasing a single event wastes an afternoon. |
| Has anything changed? | A firmware update, a new app, a new accessory. The cause is almost always the most recent change. |
| Does it happen on a fresh restart? | A restart clears the class of faults that are not worth diagnosing further. |
| Is it under warranty? | The Aqara warranty makes some of the steps below unnecessary — check before you start pulling things apart. |
Working through it
- Check per-app battery usage in settings and note anything above ten percent that you have not been using heavily.
- Disable background refresh for the worst offender and use the device normally for a day before changing anything else.
- Set the display to a fixed brightness rather than automatic for one day, to rule out a misbehaving light sensor.
- Check for a pending firmware update — battery regressions after a release are common and frequently patched quickly.
- Look at signal strength. A device held in poor coverage will burn significantly more power searching for a signal.
- If nothing changes, back up and reset, then restore apps in small batches so you can identify the culprit.
If none of that worked
If a clean install still drains quickly, the cell itself may have degraded. Most manufacturers consider a battery holding under eighty percent of its original capacity to be a warranty case within the coverage period.
Preventing a repeat
Avoid leaving the device at a full charge in a hot environment, which is the single largest contributor to long-term capacity loss. Charging overnight is fine on any device made in the last few years.
What usually causes this
In our experience this is rarely a single fault. The common pattern is an accumulation: a background process that was fine on its own, a setting changed months ago, and — on the Aqara Presence Sensor FP2 specifically — needs mains power, which narrows the margin before anything else goes wrong. That is why the steps above start with the cheap reversible checks: on a Aqara device the expensive diagnosis is almost never the one you needed.
When to call it a fault
If the behaviour persists after a factory reset, it is worth raising with Aqara under warranty rather than working around it. Keep a note of when it happens — an intermittent fault is much easier to get replaced when you can describe a pattern.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the smart home we have covered, the category archive lists every review in date order. The closest comparisons we have published are Aqara Presence Sensor FP2: Bluetooth Keeps Disconnecting and Aqara Presence Sensor FP2: Device Running Hot and Slowing Down.
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
