Online Battery Test & Health Diagnostics

Check your laptop or portable device battery charge level, AC adapter charging status, and power management telemetry.

Ready when you are

Click below to read your battery charge percentage and AC power adapter status.

Power subsystem: Integrated Battery Controller
Battery metrics are read locally with zero server reporting or fingerprinting.
Scanning Battery Subsystem Inspecting power management telemetry...
Charge Level
--%
Power Status
Detecting power subsystem...
Querying battery sensors... 0%
Battery is charging normally
Current battery capacity is at 85%. Power management subsystem operational.
98/100
Technical details & diagnostics
Battery charge level 85%
AC adapter connected Yes (AC Connected)
Battery API interface W3C Battery Status API 1.0
Power management state Healthy / Online
Battery API is Restricted in this Browser

Some browsers (like Firefox and Safari) have disabled the Battery Status API to prevent fingerprinting. Try opening HWCheck in Chrome or Edge.

  1. Open chrome://flags in Google Chrome.
  2. Ensure standard power management telemetry flags are set to Default.
  3. Reload this page to read your battery status.
  1. Microsoft Edge natively supports battery inspection on Windows and Android.
  2. Ensure your device is running on battery or connected to an AC charger.
  3. Click the retry button below.
  1. Mozilla Firefox disabled the Battery API in version 52 due to privacy considerations.
  2. To test your laptop battery online, switch to Google Chrome, Brave, or Microsoft Edge.
No Internal Battery Detected

Desktop workstation or server detected. Devices powered directly by continuous AC wall outlets do not possess an internal battery subsystem.

If you are on a laptop, ensure the battery driver (Microsoft ACPI-Compliant Control Method Battery) is active in Device Manager.
If testing an external battery pack or UPS, use manufacturer diagnostic software via USB.
Preview State:
Next recommended check Test your USB ports and devices
→

How to Test Your Battery Health Online

1
Start diagnostic
Click 'Test my battery' to query your system's onboard power controller.
2
Inspect charge telemetry
Verify current charge percentage and AC charging adapter connection.
3
Review battery health
Review power status and cycle optimization tips for maximum battery longevity.

Common Battery Problems & Fixes

Symptom Likely Cause Recommended Solution
Battery drains faster than normal Background processes, maximum display brightness, or discrete GPU usage. Open Task Manager / Activity Monitor to terminate rogue CPU-intensive processes, lower screen brightness, and turn on Battery Saver mode.
Plugged in, but not charging Underpowered AC adapter wattage, worn USB-C cable, or thermal protection. Use your laptop manufacturer's OEM charger, inspect the USB-C charging port for debris, and let your laptop cool down before recharging.
Charge % jumps or drops erratically Fuel gauge sensor calibration drift in the battery management system (BMS). Perform a full calibration: charge to 100%, run on battery until automatic shutdown at 5%, and recharge to 100% uninterrupted.
Laptop shuts down at 20–30% charge Degraded lithium-ion cells with high internal resistance under voltage load. The battery has reached the end of its chemical service life. Order an OEM replacement battery pack to avoid sudden power cuts.

Understanding Lithium-Ion Battery Degradation & Health

All modern laptops, ultrabooks, tablets, and smartphones rely on lithium-ion (Li-ion) or lithium-polymer (Li-Po) rechargeable cells. These cells operate through the movement of lithium ions between positive and negative electrodes. Over time and repeated charge cycles, mechanical stress, chemical side-reactions, and electrolyte decomposition reduce the total capacity of the cell.

A standard laptop battery is engineered to retain approximately 80% of its original design capacity after 300 to 500 complete discharge cycles. A cycle represents discharging 100% of the rated capacity, whether accomplished in a single continuous session or across several partial discharges.

Key Factors Influencing Battery Health

  • Operating Temperature: Heat is the primary enemy of lithium chemistry. Operating a laptop under heavy gaming loads on soft surfaces (like blankets or beds) that trap heat accelerates permanent capacity degradation.
  • High State of Charge (SoC): Keeping a laptop permanently connected to AC power at 100% charge places continuous mechanical stress on cell electrodes. Many manufacturers (Dell, Lenovo, ASUS, Apple) now offer 80% charge threshold limiting modes to double battery lifespan.
  • Deep Discharges: Discharging a lithium battery completely to 0% triggers copper shunts and safety shutdowns in the power management IC. It is best practice to connect your charger when capacity reaches 20%.

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Frequently Asked Questions

How does the online battery test work?
The test queries the standardized W3C Battery Status API exposed by modern web browsers to retrieve charge level, charging state, and charging time directly from your device's power management IC.
Why does my desktop PC say No Device or Unsupported?
Desktop towers, servers, and all-in-one workstations run on continuous AC wall power without an internal rechargeable lithium-ion battery. The Battery API correctly reports that no battery subsystem exists.
Which web browsers support the Battery Status API?
Google Chrome, Microsoft Edge, Opera, and Chromium-based browsers on Windows, Android, and ChromeOS provide full support. Firefox and Safari have restricted battery telemetry to protect user privacy against fingerprinting.
What causes laptop batteries to degrade over time?
Lithium-ion cells degrade naturally through charge-discharge cycles, high operating temperatures, and prolonged storage at 100% capacity. Most modern batteries retain 80% capacity after 500 complete cycles.
How can I extend my laptop's battery lifespan?
Enable battery charge thresholds in BIOS or manufacturer software (limiting maximum charge to 80%), avoid intensive gaming or 3D rendering in hot environments, and avoid fully discharging to 0%.
Is any personal device data collected during testing?
No. HWCheck operates 100% locally in your web browser. Battery percentages and power metrics are never transmitted to any external server.