विंडोज बैटरी समस्याओं का पता कैसे लगाता है?

I have a laptop that’s a little over 5 years old, and I’ve never changed the battery, so I believe Windows 7 when it tells me “there is a problem with your battery”, and to consider replacing it.

My question is: how does it detect a dodgy battery? Does the battery not have the same voltage that it used to?

Laptop batteries have a small chip inside that controls/monitors the charging process and also monitors the number of charge/recharge cycles.

This chip is factory programmed with information how this sort of battery typically degrades over time.

It also can derive information from the charging cycle itself: The time it takes to reach full-charge at a given voltage/current changes when the battery gets worn out.

(Voltage drop during discharge is not reliable as it depends a lot on the amount of current drawn while discharging, so it varies with the use-pattern of the laptop.)

Windows communicates with this chip to get information about the battery health.