Aspire 7 [A715-76G] - Battery drain problem after performing a clean windows install.

Keeping your laptop (or any charged device) plugged in after fully charged doesn't appear to damage your device but it does. In several ways.

Technically, most laptops boast of a lithium-ion battery, which will irreparably damaged if you leave it connected beyond the safe limit that has been configured as ‘fully charged’. Besides damaging the battery, lithium-ion batteries are highly reputed for starting fire when charged beyond safe limit.

For safety purposes, every (or most) laptop battery pack has a built-in charge controller in the battery. The charge controller monitors the current fed to individual cells in the battery pack, the temperature of the cells, and a few more safety parameters. If/when necessary, it stops charging the battery even when you refuse to disconnect it from power supply. Does it appear harmful? No? Read on.

As a highly experienced electronic engineer/technician that I am, one failure mode I hate to explain when presenting a failure analysis investigation is the root cause of a random component failure. Trust me, RCF doesn't usually follow pattern.

Established, any component can fail. Wrong temperature exposure, humidity, statics, accumulated shocks, and a whole lot of other technical parameters, a random component failure becomes inevitable. The mtbf of a component may be amazingly high, but I'm yet to find a component that never fails. Including resistors.

With the wide range of components embedded in your laptop battery pack, the mtbf of your battery pack is averaged 5 years.

1. On a very bad day, a damage to the current limiter for charge cut off could form a closed circuit that will enable unrestricted flow of current to the cells until the batteries explodes. Or starts a fire.
2. Your battery cells are designed to be discharged and charged with use. Not charged full ‘permanently’. When left always full, current does not flow in/out of it. This results to the cells building a passivation layer separating its anode and cathode. Drawing current from the battery is simply ‘depassivate’ the battery. Not drawing current from the cells for a long time at full passivation will make some of the layers no longer breakable. Thereby reducing the capacity of the battery
3. Theoretically, idle electronics consume 5%-10% of its rated power. In simple term, you pay money to your electricity provider for having your laptop connected all the time even without using it. Consequently - more global warming.
4. Exposure to power surge, fluctuations, etc can actually destroy your laptop.

Summarily, it's highly recommended that you unplug your devices - especially your laptop when charged to 95%-100%. Drain to 20% and charge again.

If this answers your question and solved your query please "Click on Yes" or "Click on Like" if you find my answer useful.