Lithium-ion batteries follow rules that contradict the folk wisdom many of us learned from older phones. Here are seven myths worth retiring, with the science in plain language.
Myth 1: Charge to 100% every time
Lithium cells age fastest at extreme states of charge. Keeping a phone at 100% (especially warm) accelerates chemical wear. Many phones now offer an 80% cap option — enabling it can meaningfully extend lifespan for overnight charging.
Myth 2: Let the battery fully drain occasionally
That advice applied to nickel batteries decades ago. Deep discharges stress lithium cells; 20–80% is the comfortable zone.
Myth 3: Closing background apps saves battery
Re-launching an app costs more energy than resuming it from RAM. Manually force-closing everything usually increases drain. Kill apps only if they are genuinely misbehaving.
Myth 4: Fast charging ruins batteries
Modern fast charging manages heat and tapers off above ~60%. The battery management system, not raw wattage, decides longevity. Charging overnight with a 45W brick is fine if heat is controlled.
Myth 5: Third-party chargers are always dangerous
Certified chargers (USB-IF, PD 3.0) from reputable brands negotiate power safely. The danger is uncertified no-name hardware without proper negotiation chips.
Myth 6: Dark mode barely matters
On OLED screens dark themes can cut display power noticeably in dark environments — up to 30–40% of screen power for mostly-black interfaces, less on mixed content.
Myth 7: You must use the original charger
What matters is the protocol (USB Power Delivery, PPS, or the vendor's standard) and build quality, not the logo. A good 30W PD charger charges most phones nearly as fast as the original.