I have an annoying issue with my MacBook Air (13-inch, Early 2014 on macOS High Sierra Version 10.13.6): A few minutes after disconnecting the power cord from my fully charged laptop, it goes to sleep. I can restart it (even without connecting it to power though it will go to sleep again), and my system's clock is set to 1st January 2019.
Does anyone have a suggestion how I can prevent my laptop from going to sleep or which changes (battery replacement or other) would need to be made?
As long as it is connected to power there is no problem, but I would like to solve the issue. So far, I have reset the system management controller (SMC) (https://support.apple.com/en-us/HT201295) which unfortunately did not change anything. I also unchecked the "Put hard disks to sleep when possible for both the Battery and Power Adapter settings of the 'Energy Saver' (see below), which unfortunately also did resolve the problem.
Assuming that this issue is related to my battery, I found this stack exchange post (Fully charged MacBook Air turns off when power cord removed) and tried the following Terminal command, which gives me the following:
system_profiler SSPPowerDataType | grep -i "charge information" -A 10
Charge Information: Charge Remaining (mAh): 5412 Fully Charged: No Charging: Yes Full Charge Capacity (mAh): 5558 Health Information: Cycle Count: 679 Condition: Normal Battery Installed: Yes Amperage (mA): 332 Voltage (mV): 8444
Interestingly, the same command gave me an Amperage reading of 0 (zero) yesterday. Not sure what use the reading is when my laptop is connected to power, but that's what it says today.
I'm also worried that my power cable should be replaced (see below, really being honest that I know very little about electricity and battery tech):