T520 Battery Discharges Inconsistently

So I have the T520 that I bought about 3 months ago. I have it plugged in most of the time with the battery charge threshold set to 80%. I use the laptop unplugged every once in a while (once a week or two).

However, over my last few "battery exercise" cycles, I noticed that the battery doesn't hold for more than 1.5 hours (with the charge of 80%). It used to hold about 4-5 hours before.

Moreover, the battery drains inconsistently. It takes probably a little over an our for the battery to drain from 80% to about 45-50% and then it goes down to 6% within minutes.

I was wondering why my battery is dying so prematurely. Even if a battery reset is required to deal with the inconsistent discharge, I am still concerned with the overall battery life (from 80% to 6% within less than 1.5 hours).

What do you, guys, think the problem might be? Thanks.

 

check the thinkvantage power manager's battery information tab, in there a listing of the battery information is available for you.

Have a look at full charge capacity, design capacity and the number of charge cycles.

 

Thanks. It shows that the condition is good. Design capacity 56.16 Wh, remaining capacity 46.88 Wh (at 80% remaining charge), full charge capacity 58.95 (probably, will reset to a lower value if the battery is reset). Cycle count 22. Doesn't make any sense. According to this, the battery should be in a good shape.

 

Did you try performing a reset yet?

 

I have it set to "Notify me when reset is recommended". It never told me to reset. I will try anyway but, as mentioned, I can't see how this may help the short battery life problem.

 

Did any of your power plan settings change?

 

Maybe one of the cells went bad?

 

no. i haven't made any changes to the power plan.

 

how can I find out if it is a bad cell? at least from the battery info, it looks like it has the full charge capacity close to the design capacity.

 

The sudden drop seems like a weak cell.

There's probably a relevant article here, but I can't seem to find it.
Battery Information Table of Contents, Basic to Advanced

 

First I would check that the power drain is in the 10-12W range (needed to get 4 to 5 hours run time from a full battery).

If that's OK then the the reset would be the next step. Hopefully the process is clever enough to figure out that something isn't OK. Then it's over to Lenovo to request a replacement.

John

 

Update: Battery Gauge Reset solved the problem. Took forever to complete though Thanks to everybody for suggestions.