Searched: what is battery wear level
Reference URL: https://forums.tomsguide.com/threads/battery-wear-level-problems.395424/
As a battery gets older, it loses capacity. If the battery's capacity when new was 4000 mAh, and its current capacity is only 3600 mAh (90% of new), then it has a battery wear level of 10%.
That said, battery wear is mostly caused by deep charge cycles. That is, charging to 100% and discharging to 0%. Shallow cycles (say, charging to 70% and discharging to 30% put almost no wear on the battery.
http
/batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Newer laptops (and phones, and electric vehicles) are programmed not to fully charge nor discharge the battery in order to prevent wear and maintain battery longevity. One of the ways I've seen some devices do this is by "faking out" Windows into thinking the battery has more wear than it really does. So the battery may be 4000 mAh when new, but the battery tells Windows it has 10% wear. This prevents Windows from charging it past 90%, thus preventing a deep cycle.
This is just one of the wear-prevention strategies out there, and I don't know if the ASUS X205TA is using it. So it could just be reporting a fake wear level to Windows. OTOH if the original owner let the battery discharge completely and left it that way, it may have self-discharged past 0% enough to damage the battery and the reported wear level may be accurate.
The only true test will be to monitor the wear level over several months of use. If it holds steady between 15%-20%, then it's probably nothing to worry about. If it continues wearing quickly, then the battery may have been damaged by the previous owner. (Measuring battery capacity and wear level is a bit of a black art, as it requires extremely accurate measurements of voltage. Things like discharge rate and temperature can drastically change the results, so a +/- 3% change in wear level day-to-day is not unusual.)
That said, battery wear is mostly caused by deep charge cycles. That is, charging to 100% and discharging to 0%. Shallow cycles (say, charging to 70% and discharging to 30% put almost no wear on the battery.
http
/batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteriesNewer laptops (and phones, and electric vehicles) are programmed not to fully charge nor discharge the battery in order to prevent wear and maintain battery longevity. One of the ways I've seen some devices do this is by "faking out" Windows into thinking the battery has more wear than it really does. So the battery may be 4000 mAh when new, but the battery tells Windows it has 10% wear. This prevents Windows from charging it past 90%, thus preventing a deep cycle.
This is just one of the wear-prevention strategies out there, and I don't know if the ASUS X205TA is using it. So it could just be reporting a fake wear level to Windows. OTOH if the original owner let the battery discharge completely and left it that way, it may have self-discharged past 0% enough to damage the battery and the reported wear level may be accurate.
The only true test will be to monitor the wear level over several months of use. If it holds steady between 15%-20%, then it's probably nothing to worry about. If it continues wearing quickly, then the battery may have been damaged by the previous owner. (Measuring battery capacity and wear level is a bit of a black art, as it requires extremely accurate measurements of voltage. Things like discharge rate and temperature can drastically change the results, so a +/- 3% change in wear level day-to-day is not unusual.)