Acer Aspire 3 A315-59G Battery issue when it reaches to 100% and unplug the charger it drops to 99%

You have a very small 45W power adapter, and it will take time to fully charge the 3-cell battery to 100%, it is normal for the battery meter to show 99% when the power adapter is disconnected. This is a new laptop with presumably a new battery so you must do one full charge cycle for BIOS and MS ACPI battery protocol to register a new battery capacity, failing to do so will result in inaccurate battery statistics and power issues: Disable Hibernate and Fast Startup in Power Plan "Change what closing the lid does" and "Change settings currently unavailable". Change the Power Plan to Balanced and reset that plan to factory defaults as you may have edited the advanced power plan settings. Shut down the correct way with Start on the task bar and clicking on the Power-Shutdown icons. Disconnect all peripherals, USB devices and external monitors/docking stations, etc. from the laptop, close the lid and plugin the 45-Watt power adapter with the round DC barrel plug that came with the laptop. Charge till the amber battery LED turns blue and give it another 15 minutes to make sure the battery is 100% charged, open the lid, boot to Windows and verify the Battery Meter reads 100%, unplug the adapter and work with the laptop till it shuts down automatically (discharged to 3-4%). close the lid, connect the adapter again and don't open the lid or try to boot. Charge again till the battery light turns from amber to blue and add an extra 15 minutes. That's it.