Battery usage question

After one recent use of the short battery power of my t420s, my battery capacity drops from 100% to 85% (36.5Wh). I've only used 9 cycles since I got my t420s, 7 weeks ago. My battery is set to charge at 42% and stop at 94%. Normally I plug it in to charge around 20-25%. I've been using battery power once or twice a week to keep it flowing..

Is there anything I did to cause this large loss? I would assume that it would degrade gradually in smaller increments. any changes I should do to increase battery life or proper battery usage? is this battery faulty or is this normal behaviour? not too sure what battery warranty covers.

any input is appreciated

 

Do you remember the battery capacity when you got the laptop?
You might have received a defective one such as one with a dead cell.

 

I remember it being around 42-43Wh, lower than specified design capacity of 44Wh. Would this be considered defective and be covered by warranty?

 

I would first change the battery maintenance setting to let the battery charge to 100% and then (after making sure that the charging cycle happens) recheck the fully charged capacity. If the capacity is still low then use the button on the battery maintenance page to perform a battery gauge reset and further recharge.

If it is still low then talk to Lenovo. An early loss of capacity does not bode well for the future.

BTW, who is the battery manufacturer?

John

 

thanks john, i'll give it a try

the manufacturer is Panasonic according to HWiNFO32

 

I charged it to 100% and it went up to 91% ( 39.29 Wh) full capacity. After doing a Battery Gauge Reset, 6 hours long, the full capacity went back to 100% (44.06 Wh) !

Problem Solved! I guess it just needed to recalibrate actual full charge capacity

 

Thanks for the update. Happy to hear that the recalibration fixed the issue.

BTW, the Panasonic batteries are usually some of the better ones. IIRC, Sanyo hasn't got such a good track record.

John

 

Another thing to keep in mind is the power manager setting to automatically manage the battery. If you are on this setting and you don't discharge the battery below something like 25-40% once in a two week period it will automatically lower "full charge" to be about 80% of full capacity. Once you use the battery below that threshold it will go back to the full capacity. This behavior is meant to extend your battery life. If you don't like it, do not set it to automatically manage the battery.

 

Hmm. That's interesting. I'm going to give that setting a try, see how I like it. I'm sure it should give the correct method of extending battery life