7 charging habits that secretly kill your battery (and what to do instead)

Modern lithium-ion batteries are tougher than ever — but they still age. The good news? Most of the damage comes from a handful of habits and a poor-quality charger, not from the battery being "defective." Fix those, and you can keep your phone feeling new for far longer.

Below are the seven most common battery-killers, ranked roughly by how much harm they do.

1. Using a cheap or failing charger

A low-quality or damaged charger can deliver unstable voltage, run hot, and stress the part of your phone that manages charging (the PMIC). This is the single biggest thing most people get wrong — and it's invisible until damage is done. If your charger gets very warm, charges slowly, or has a frayed cable, treat that as a red flag.

Not sure if your charger is safe? Run the free Charger Health Analyzer →

2. Letting it cook in the heat

Heat is a battery's worst enemy. Charging under a pillow, on a hot car dashboard, or while gaming for hours pushes the temperature up and accelerates wear. Keep charging in a cool, open spot.

3. Always draining to 0%

Deep discharges to 0% stress the cell. You don't need to baby it, but topping up before it gets critically low is gentler than running it flat every day.

4. Obsessing over 100%

Sitting at a constant 100% (especially overnight, while warm) keeps the cell under tension. If your phone supports "optimised" or "adaptive" charging, turn it on — it holds at ~80% and finishes just before you wake.

5. Fast-charging everything, all the time

Fast charging is fine occasionally, but constant high-wattage charging generates more heat. For overnight charging, a slower charger is actually kinder to the battery.

6. Cheap, mismatched cables

A damaged or underspecced cable can cause voltage drops and heat. Use a good-quality cable rated for your phone's charging speed.

7. Ignoring the warning signs

Swelling, a hot back, rapid percentage drops, or random shutdowns are signals — not quirks. Catch them early.

The simplest way to check where you stand

Rather than guess, you can get a clear read on your charging setup in about 90 seconds. Our Charger Health Analyzer walks you through five quick questions and gives you a 0–100 score plus specific fixes.