Battery test: charge level and charging detection

This test shows charge level and charging status live – and answers the more important question: how do you find the true battery health no browser can measure?

What this test shows – and what it can't

The browser can read charge level and charging status (on Android). That enables one genuinely useful check: charging detection. If the status flips to "charging" the instant you plug in, cable, charger and port are electrically fine. If it only reacts in certain plug positions, the port is likely dirty or worn – in fact the most common cause is simply compacted pocket lint in the port. Many people remove it carefully with a wooden or plastic toothpick (power the phone off first, never use metal) – but that's at your own risk; the safe option is having it cleaned at a repair shop.

True battery health – how much capacity remains – cannot be measured by any website. Use your system's built-in tools:

• iPhone: Settings → Battery → Battery Health shows maximum capacity in percent.
• Android: depending on the manufacturer under Settings → Battery or device care/diagnostics; many phones also show battery data after entering a diagnostic code in the phone app.

When a battery is worn out

Lithium batteries age with every charge cycle. Rule of thumb: below roughly 80% remaining capacity, everyday performance noticeably degrades – shorter runtime, sudden shutdowns in cold weather or at low charge, throttled speed. A battery replacement is possible on almost every device and is one of the most worthwhile repairs: it costs a fraction of a new phone and often adds years of use.

Take warning signs seriously

A swollen battery (display bulging, back cover lifting, device no longer lying flat) is a safety risk: stop charging, don't press on it, have it replaced professionally soon and store the device somewhere cool. A device that gets unusually hot while charging also belongs in professional hands.