My Samsung Galaxy S25 was at 4% when I connected it to my usual Samsung fast charger. The battery percentage started increasing much faster than normal, and when I checked about five minutes later, the phone said it was fully charged. It has not dropped below 99% while I have been using it.
The battery has otherwise behaved normally, aside from the expected gradual reduction in battery life. I restarted the phone shortly afterward, and the displayed percentage immediately returned to what seemed like the actual level. This makes it seem like a temporary battery-monitoring or software display glitch, but I am wondering whether it could indicate a problem with the battery or charging system.
3 Answers
It sounds like the battery fuel-gauge reading briefly failed or became stale. A restart can make the phone poll the battery statistics again. If it keeps happening, install any available system updates and watch for unusual heat, rapid real-world discharge, unexpected shutdowns, or swelling. Those symptoms would justify having the phone inspected.
This was probably a temporary software glitch in the battery percentage display rather than the phone actually charging from 4% to 100% in five minutes. Restarting forced the system to read the battery information again, which explains why the percentage corrected itself.
Phones do not directly measure the exact amount of charge left in a lithium-ion battery. A fuel-gauge chip estimates it by tracking voltage, current, temperature, and charge entering or leaving the battery. Those estimates can drift or occasionally become confused, causing the displayed percentage to jump. The charging hardware also has protections against overcharging, excessive discharge, and unsafe temperatures, so a one-time incorrect reading is not usually a reason to panic.
That seems likely. The percentage went back to normal after the restart, so I’ll keep an eye on it and see whether it happens again.