Heat is the biggest enemy of lithium-ion batteries. Some warmth during charging is normal, but excessive heat accelerates chemical degradation. Charging a phone inside a thick case or under direct sunlight is one of the most common mistakes that shortens battery lifespan.
Charging to 100% every night and leaving the phone plugged in until morning can contribute to capacity loss over time. Modern phones include smart charging features to reduce this risk, but keeping the battery between roughly 20% and 80% is still considered the safest general approach.
Using uncertified or cheap chargers can cause voltage fluctuations that age battery cells prematurely. A PD-compliant charger and cable with proper safety protections largely removes this risk.
The old habit of fully draining and fully charging a battery, sometimes called 'calibration,' made sense for older nickel-based batteries but is unnecessary and can even be harmful for lithium-ion cells. Short, frequent charging cycles put far less stress on the battery.
Charjett's overcurrent and overheat-protected chargers are designed to reduce some of this everyday risk at the hardware level, but the real difference comes from pairing good hardware with the right daily habits.