Charging Habits That Quietly Age Your Battery

Battery ageing is cumulative and mostly boring. The factors that matter are well understood, and most of them are about temperature and state of charge rather than about the charger brand.

What actually shortens life

• Heat. This is the single biggest factor. Charging under a pillow, in direct sun, or while running something demanding all raise the temperature of the cell.
• Sitting at 100 percent. A battery held at full charge for hours ages faster than one that spends time in the middle of its range.
• Deep discharge. Running to zero regularly is harder on the cell than topping up.
• Fast charging in a hot environment. The combination is what costs, more than either on its own.

Habits worth changing

• Take the case off, or at least stop insulating the phone, while fast charging.
• Avoid charging in a hot car or in direct sunlight.
• If your phone offers a charge limit or optimised charging, use it.
• Top up in small amounts during the day rather than one long charge overnight.

Habits not worth worrying about

• Charging overnight in general. Modern phones stop drawing current once full.
• Using a higher-wattage charger than the phone came with. The phone negotiates what it accepts.
• Unplugging the moment it hits 100 percent. The difference is negligible next to the effect of heat.

If you remember one rule, make it this: keep it cool.