from 3% wear to 7% n 1 day?

[Gaziki]

I had 2% battery wear from day I bought a tablet which was around 3 months ago. Recenty it drop from 18.21 to 18.11 over one day and battery wear changed from 2-3%. I run some battery wear "fix" which was fully discharge and then run bios test. It doesnt changed values. Weirdly next day battery wear changed back to 18.21. Today, after 1 day it changed to 7% wear according to HW monitor and bios tests, including "my dell" data. I mean WTF. This tablet has soooo many problems and now this also? ....

 

[gpobernardo]

I had 2% battery wear from day I bought a tablet which was around 3 months ago. Recenty it drop from 18.21 to 18.11 over one day and battery wear changed from 2-3%. I run some battery wear "fix" which was fully discharge and then run bios test. It doesnt changed values. Weirdly next day battery wear changed back to 18.21. Today, after 1 day it changed to 7% wear according to HW monitor and bios tests, including "my dell" data. I mean WTF. This tablet has soooo many problems and now this also? ....

Battery wear is a natural and unavoidable phenomenon for lithium-based rechargeable batteries, as a consequence of the chemical irreversibilities that result from the discharge-charge cycle. We can only do our best to minimize battery wear (except if we work in the R&D department of a company that produces such battery). The way to minimize such wear is by not subjecting the battery to huge charge-discharge gaps, e.g. differences of greater than 50%, i.e. discharging your phone to less than 50% and then charging it fully to 100%. The best we can do is to keep the charge between 70-80%, but that is rather impractical for a mobile battery.

Fully draining* the battery and then charging it completely does not get rid of battery wear - it worsens it. BUT, this process "re-calibrates" the battery circuitry and resets its battery wear count. The battery wear is STILL there, but it is just ignored. This is exactly the reason why the battery circuitry re-calibrates after a "full" discharge.

As for the other problems of your tablet, I have no comment.

*- In most cases you're actually not fully draining the battery, but merely going below the lowest threshold limit set by internal battery circuit, e.g. the circuit may say "0%" when there actually is still 5% remaining. This is because truly draining a lithium-based battery will prevent it from being recharged, hence killing the battery.

 

[Gaziki]

Well, i alway try to dry as much baterry possible before fuly charge, because i thought its healthier for the battery. Never or less ism cnfused y thouse numer. Batter shouldnt drop from 3 to 7% per day and durig ne est back to 4%.

 

[gpobernardo]

Well, i alway try to dry as much baterry possible before fuly charge, because i thought its healthier for the battery. Never or less ism cnfused y thouse numer. Batter shouldnt drop from 3 to 7% per day and durig ne est back to 4%.

Hopefully the information above would change your battery-related habits.

 

[Gaziki]

I dont get it why it jumps from 5-8% in oine day and got this 5% wear in just 3 months... . Shall I return it?

 

[gpobernardo]

I dont get it why it jumps from 5-8% in oine day and got this 5% wear in just 3 months... . Shall I return it?

The hassle you would go through in returning the device/battery would be greater than the trouble caused by that amount of battery wear. 5% wear in three months is still acceptable, especially if you're still repeatedly "drying" your battery up each charge cycle.

Again, you can minimize battery wear by avoiding huge discharge-charge gaps... but that's the purpose of a battery, after all - it's not meant to last. Rather than returning the battery, you may want to buy a spare battery instead (but probably only when the %wear reaches around 30-40%).

The small changes in battery wear % in one day is just a matter of calibration - batteries are not like graduated cylinders where you can always measure its (energy) content accurately. As long as the change in %wear doesn't exceed +/-10% per day, you're fine (provided that it doesn't keep on increasing each day!).

 

[Gaziki]

Today i did full discharge and run bios test and battery life jumped to 4% wear... . I know what u mean, but when it says I have 8% wear for example does it mean battery is charged by 92% of its durability or 96% in my case?

 

[gpobernardo]

Today i did full discharge and run bios test and battery life jumped to 4% wear... . I know what u mean, but when it says I have 8% wear for example does it mean battery is charged by 92% of its durability or 96% in my case?

Yes. If your battery had a total factory capacity of 100mAh*, then 4% battery wear means you can only charge fully up to 96mAh. Hence, 100% charge (if the battery was re-calibrated) would only be 96mAh out of 96mAh instead of 100mAh... and 50% charge would be 48mAh out of 96mAh.

For my laptop, after four years of ownership, it says that the battery wear is 4.5% out of 48,840 mWh**. This means it has only 46,620 mWh usable energy storage left. In line with this, my battery says it's charged to 100% - 46,620 mWh out of 46,620 mWh (not out of 48,840 mWh).

In effect, as the battery wear increases, the total usable energy storage capacity decreases... so 100% charge now would last longer than 100% charge next year for the same battery with regular use.

*- Only as an example, since this value is ridiculously small for modern battery capacities.
**- Units differ depending on convention, but these are all energy capacity units.

 

[Gaziki]

Yes, but I mean my battery life jumps from 4-7%(for now) every full charge. If its 8% use it will take this exztra 4% life so I will have to charge it earlier or its just calibration bug, because real battery wear is around 4%?

 

[gpobernardo]

Yes, but I mean my battery life jumps from 4-7%(for now) every full charge. If its 8% use it will take this exztra 4% life so I will have to charge it earlier or its just calibration bug, because real battery wear is around 4%?

Did you mean your battery wear?

That "jump" is just a matter of calibration, since most batteries are do not really accurately measure its own battery wear but they rather just estimate the wear based on the fluctuation in the output voltage compared to a factory-specified baseline - to be able to determine the exact amount of battery wear needs atomic-level microscopic analysis of the battery material itself, which is expensive and time-consuming (given the current commercial technology).

But let's keep things simple. The bottom line is: don't be bothered much by small fluctuations in battery wear values (+/-10%). If you're going to use it, charge it to 100%. If you're going to keep it in a shelf for a prolonged period of time, keep it with a charge of around 60%. As much as you can, don't let your battery charge go below 20% - this way you won't have to bothered by battery wear.