Fear of overcharging the battery i leaving the phone on the charger throughout the night was once justified, but modern smartphones come with advanced hardware and software protections. Many manufacturers today implement visual indicators that make it clear to users that the system is actively protecting the device.
On Samsung phones (starting with One UI 7), the shield icon inside the battery indicates that maximum battery protection is activated. This symbol is a clear sign that the phone has reached a predefined limit and the software has cut off the power supply to prevent chemical stress and overheating. Charging will continue only when the percentage drops below the set limit, and then the shield icon will be replaced by the classic lightning bolt again.
In addition to the shield, the status bar may also appear leaf iconwhich has a completely different role. This icon indicates that the phone is in battery saving mode (Power-saving mode).
How to choose the appropriate battery protection mode
Within the battery settings on newer Samsung Galaxy devices, users have two main options to preserve battery longevity:
- Basic. This is the default operating mode. The phone charges up to a maximum of 100%, after which the system completely stops charging. Only when the battery is naturally discharged to 95%, the charger is activated again to top up the device.
- Maximum. By activating this mode on the One UI system, the user gets a slider with which he can manually limit charging to 80, 85, 90 or 95%. It is in this mode that the aforementioned shield icon appears.
Why charging up to 100% is harmful (according to science)
Although it seems logical to always charge the phone to the end in order to have maximum autonomy, constantly tanking battery up to 100% drastically shortens its life. This happens due to the chemical processes inside lithium-ion batteries, reports BGR.
During an electrochemical reaction, ions move from the cathode to the anode inside the cell. The greatest stress and pressure on the entire system occurs precisely in the final phase of charging. It is in the range of 80-100%. Limiting the charge to 80% maintains thermal stability and prevents excessive battery heating during cycling.
In addition to software limitations, external factors also affect battery health. Avoid charging your phone in bulky covers that dissipate heat poorly and never use untested and unsupported low-quality chargers.