Battery Health Test | Check Controller and Device Battery
Read your controller's battery level over Bluetooth and track how it changes over months, or check your laptop or phone's own battery. Works as a battery health test, battery health tester, or controller battery checker.
Reading history
No readings saved yet for this controller
Battery level is instant, battery health is a trend that only appears across multiple readings.
Pair first
Pair your controller with your operating system's Bluetooth settings before using this page.
Connect
Click connect controller and pick it from the browser's native device picker.
Reading is saved
Each successful reading is saved locally with a timestamp, building a history over time.
Repeat over weeks
Check back periodically at full or near full charge to build a meaningful history.
See the trend
Once enough high charge readings exist across enough days, the degradation trend appears.
The current level is unambiguous, what matters more is whether that level is declining over time.
| Reading | What it tells you |
|---|---|
| 75 to 100% | Ready for an extended session, a healthy battery consistently reaches this range on a full charge. |
| 50 to 74% | Comfortable for a typical session with substantial runtime remaining. |
| 25 to 49% | Plan to charge before your next long session, lithium ion cells generally prefer staying above 20 percent. |
| Under 25% | Charge soon, repeatedly discharging deep below 10 percent accelerates capacity loss over time. |
| Decline trend | Under 0.5% per month is normal, 1 to 2% per month is moderate aging, over 2% per month sustained suggests the battery is nearing end of life. |
Lithium ion batteries lose a small percentage of their maximum capacity with every charge cycle, slowly at first and then accelerating as the cell ages. A controller reports its level as a percentage of its current maximum capacity, not its original one, so a fresh looking 100 percent reading on a battery that has degraded still means full of a smaller total capacity than the day it was new. A single reading cannot reveal that loss, only a trend across weeks and months can, which is exactly why this tool emphasizes repeated readings over any one number.
The reported percentage itself is also an approximation. Controllers estimate charge from voltage rather than measuring remaining capacity directly, and that estimate is genuinely noisy, individual readings can vary 5 to 10 percent for the same real state of charge. Requiring at least 5 near full readings spanning a full week before showing a trend is what filters that noise out and leaves a signal worth trusting.
Not every controller exposes battery through the standard Bluetooth service this tool reads.
Picker shows an empty list
Confirm the controller is paired with your operating system and currently powered on and connected.
Read the fixBattery drains faster than it used to
A shorter time between charges is often the first sign of the capacity decline this tool tracks.
Browse the Fix guidesAlso check connection stability
A weak Bluetooth connection can affect both battery reporting and general reliability.
Run the Connection Stability TestRun the full controller benchmark
Battery health is one part of overall controller condition. Run every diagnostic in sequence for one overall score.
Run the benchmarkWhat is a battery health test
A battery health test, or battery health tester, checks the current charge level of a battery and, when repeated over time, reveals whether the battery is still reaching a full, healthy charge or is losing capacity as it ages. A single reading only shows current charge, health is a trend across many readings.
How does the battery health test controller mode work
Your controller must already be paired with your operating system's Bluetooth settings. Click connect controller, and your browser opens a native device picker using the Web Bluetooth API. Selecting your controller reads its standard battery service characteristic and displays the current level.
Why does the controller battery reading require Chrome or Edge
Reading a Bluetooth device from a web page requires the Web Bluetooth API, which only Chromium based browsers implement. Safari and Firefox have not shipped Web Bluetooth for privacy and security reasons, so those browsers deliberately limit what a website can do with paired hardware.
My controller does not appear in the Bluetooth picker, why
The controller must be paired with your operating system first, the browser can only see already paired devices, it cannot initiate pairing itself. It also needs to be powered on and actively connected rather than simply paired but off. Try putting it back into pairing mode briefly and reopening the picker.
Why does my Nintendo Switch Pro Controller not show a battery reading
The Switch Pro Controller does not expose battery information through the standard Bluetooth battery service that this tool reads. Nintendo uses its own proprietary protocol for that data, which standard Web Bluetooth cannot access. Check the battery indicator on the Switch home screen instead, this is a limitation of the controller, not the tool.
Does this test my laptop or phone's own battery too
It attempts to, using the browser's Battery Status API where available. Many modern browsers have removed or restricted that API over privacy concerns, so device battery reading may be unavailable, in which case this page shows the correct operating system steps to check your device's own battery health instead.
How accurate is a controller's reported battery percentage
It is only as accurate as the value your controller itself reports, which is an approximation derived from voltage rather than a direct capacity measurement. Individual readings can vary by 5 to 10 percent for the same real state of charge, which is why tracking the trend across many readings matters more than trusting any single number.
How many readings do I need before I see a degradation trend
At least 5 readings taken at 90 percent charge or higher, spanning at least 7 days. Below that threshold, ordinary reading noise overwhelms any genuine signal, so the tool is explicit that it does not yet have enough data rather than guessing.
What counts as a healthy battery decline rate
Under roughly 0.5 percent capacity loss per month is normal for a healthy lithium ion battery. 1 to 2 percent per month suggests moderate aging. Sustained decline over 2 percent per month suggests the cell is approaching the end of its useful life, typically 18 months to 3 years of regular use for controller class batteries.
Will testing my battery repeatedly damage it
No, in any meaningful sense. Reading a battery characteristic once per connection uses a negligible amount of power. You would need to refresh the reading hundreds of times in a row to use even a single percent of charge.
Does this work with an Xbox controller's battery
Yes, over a standard Bluetooth connection, though not over the proprietary Xbox Wireless protocol some Xbox controllers use with a dedicated dongle, which does not expose the standard battery service this tool reads.
Where is my battery history stored
Locally in your browser only, using local storage on your own device. It is not uploaded anywhere, and switching to a different browser or computer starts a fresh history, so use the same browser consistently for the best long term trend.
Do I need to install anything for this battery health tester
No. The tool runs entirely in your browser. There is nothing to download and no account to create, though the live controller reading specifically requires a Chromium based browser as noted above.
Does this work on mobile phones
Controller battery reading works on Android Chrome, which supports Web Bluetooth. iOS Safari does not support Web Bluetooth, so controller battery reading is not available there, though this page's educational content and OS instructions work on any device.
Is my battery data sent anywhere
No. Every reading is processed and stored locally in your browser and is not sent to a server unless you choose to export a report yourself.