This article only applies to: Acer Nitro models
Some Acer Nitro models have a switch that will disable the battery when the RAM access door is removed. If the door is not reinstalled correctly, the system will not operate without the AC adapter connected. This may occur after the system has been opened to install or replace RAM.
Check the RAM access door to make sure it is installed properly and the screw tightened. The image below shows the location of the switch that disables the battery.