Charging your phone to 100 percent every single night causes only a small amount of extra long-term wear on the battery, and modern phones are built to handle it. There is no traditional overcharging, because the phone stops drawing power once it is full. The bigger factors in battery aging are heat and sitting at a high charge for long periods.
Why this happens
Phone batteries are lithium-ion, and they age slightly faster when kept at a very high charge level and when they get hot. Sitting at 100 percent overnight combines both to a mild degree, which is why a full charge is a little harder on a battery than a middle charge.
However, overcharging in the old sense does not happen. Once the battery reaches 100 percent, the phone stops charging and runs on the adapter, topping up only as needed. Many phones also add optimized charging, which holds the battery lower until shortly before you usually wake up.
Is this normal?
Yes. Charging overnight is extremely common, and phones are specifically designed to be charged this way safely every day.
Does it cause any problems?
The only real effect is slightly faster capacity loss over the years, so after a couple of years you might notice the battery does not last as long as when new. With a genuine, undamaged battery and charger it is not a safety hazard.
How to fix or check it
- On iPhone, open Settings, then Battery, then Battery Health and Charging, and turn on Optimized Battery Charging.
- On Android, the wording varies by brand. Look under Settings, then Battery, for options like Adaptive Charging, Protect battery, or a charging limit. Samsung phones offer Protect battery, which caps charging to extend lifespan.
- Keep the phone cool while charging. Remove a thick case if it gets warm, and do not charge under a pillow or blanket.
- If your phone offers an 80 or 85 percent charge limit, using it reduces long-term wear.
- Check battery health over time. On iPhone it is under Settings, Battery, Battery Health. On Android it varies by model; some show it in Settings or Device care.
Frequently asked questions
Does leaving it plugged in overnight overcharge the battery?
No. The phone stops charging at 100 percent and will not force more power into a full battery.
Should I keep the battery between 20 and 80 percent?
That range is gentlest for long-term health, but it is not required. Charging fully is fine for everyday use.
Can charging overnight cause a fire?
It is very unlikely with a genuine, undamaged battery and a quality charger. Damaged cables or cheap uncertified chargers are the bigger risk.