How to check battery health on a refurbished iPhone or Android phone

Verify the actual battery capacity of a refurbished phone before buying — works on both iPhone and Android. Identifies aftermarket replacements and worn-out cells.

Verify the actual battery capacity of a refurbished phone before buying — works on both iPhone and Android. Identifies aftermarket replacements and worn-out cells. Total time: about 3 minute( second(s)).

• Step 1 — iPhone — Settings path: Settings → Battery → Battery Health & Charging. Look for Maximum Capacity (must be 85%+ for refurb-grade Excellent or higher).
• Step 2 — iPhone — service warning: If you see 'Service' under Battery Health, the cell needs replacement. Refurbished iPhones from a reputable seller should never show this.
• Step 3 — Android — manufacturer apps: Samsung Members → Battery diagnostics. Pixel uses Settings → Battery & device care → Battery → Battery health.
• Step 4 — Run a load test: Stream 4K video for 15 minutes with brightness at 80%. Record the % drop. Healthy cell drops 10-15%; degraded cell drops 25%+.
• Step 5 — Cross-check certification card: Reputable refurbishers (like Gadget Rebirth) include a certification card with the documented battery health at packing time. Compare on-device reading to the card — they should match within 2-3%.