Thinkpads Forum

Hi, I have an X60s with 8-cell battery since December last year (6 months ago). Now I'm starting to wonder about my battery full charge capacity that went down from 74.88 Wh to now, 67.82 Wh. Is it strange? Here are some of my battery info:

Cycle count: 77
Manufacturer name: SANYO
Manufacture date: 2006-09-25
First use date: 2006-12
FRU part number: 93P5029
Design capacity: 74.88 Wh
Full charge capacity: 67.82 Wh

Thanks in advance.

hmm... my 2-month-old X60t 8-cell battery has the opposite problem:

Cycle count: 9
Manufacturer name: SANYO
Manufacture date: 2007-03-28
First use date: 2007-4
FRU part number: 42T4507
Design capacity: 66.24 Wh
Full charge capacity: 70.38 Wh

fongj wrote:hmm... my 2-month-old X60t 8-cell battery has the opposite problem:

Cycle count: 9
Manufacturer name: SANYO
Manufacture date: 2007-03-28
First use date: 2007-4
FRU part number: 42T4507
Design capacity: 66.24 Wh
Full charge capacity: 70.38 Wh

Your battery is awesome

fongj wrote:Design capacity: 66.24 Wh

weird?
Does anyone else has design capacity like this?

@RT wrote:Now I'm starting to wonder about my battery full charge capacity that went down from 74.88 Wh to now, 67.82 Wh. Is it strange?

I'd say that's more or less average. All they guarantee is more than 50% after 6 months. Mine is down to 73.27 (it was 68 or so last week, but went up again after recalibration), cycle count is 24, first used 10/06.

My office laptop (T42) is on 34.54 (design 47.52) after 63 cycles, first used 8/05, which is above average I guess. The extra battery (in the ultrabay) is on 17.17 (design 23.76), cycles 45, first used 11/05.

Batteries are essentially (very expensive) consumables and need to be replaced every 2-3 years or so.

Regards, Martin

Design: 66.24
Full charge: 71.85
never calibrated though

Similar to the original poster, I bought and started using an x60s last November. I bought an 8-cell and a slim 4-cell. The 8-cell is Sony; the 4-cell is Sanyo.

Similar to the other posters, the Sanyo slim 4-cell showed, originally, a design capacity of about 28.8 and a full charge capacity of about 32. The full charge capacity gradually decreased to just below the design capacity at about 45 cycles (memory is a little hazy). I do not have the 4-cell memory with me.

The Sony 8-cell is at cycle count 95 and still shows, and has always shown, both design and full charge capacity at 74.88. When I got the computer, I set it to optimize battery life and have done nothing else to either battery.

In usage, I normally use the slim 4-cell first until it is low, then switch to the 8-cell. So, I regularly discharge the 4-cell to about 5% while the 8-cell normally goes down only to about 30% power left.

My guess is that Sanyo actually shows the true charge capacity while the Sony may have the electronics set to never show more than the design capacity. Also, someone once said on this BBS that batteries last longer if they are not discharged to less than 25%. If the blessing of my 8-cell is due to it being rarely fully discharged, then I wonder how long I could last on 2 8-cell batteries by only using each for one-half of the day. I'll probably never know the answer.

@RT wrote:

fongj wrote:Design capacity: 66.24 Wh

weird?
Does anyone else has design capacity like this?

My design capacity is that exactly. I have a 6365-CTO that was purchased about 3 months ago. I have 47 Cycles on my battery as of now.