Extended vs. regular battery for T40?

[cmp]

I'm replacing the battery on my T40 before passing it on to a coworker, and wanted to see if anyone had experience with the extended battery for the T4x series. Is it significantly better than the regular 6 cell battery? Is it too noticably heavier or bulkier? I never got particularly brilliant battery life with the regular battery in the T40 (although it was passable), so an improvement would be great.

Any thoughts or comments would be helpful, as I can't seem to find many reviews online about this particular issue. Thanks.

[jch]

I would definitely recommend the 9-cell battery.

I have a T41p (2373-9HU) with a one-month-old 9-cell. (Manufacture date: 07/2006)

I get 6-8 hours on it. Its working capacity is currently 79.6 Wh (Watt-hours), meaning that at my typical usage of 12-15 Watts, it'll last 5-1/2 to 6-1/2 hours. Obviously, playing movies would use much more juice.

Previously, I had a 6-cell (which was 12-months old when IBM sold it to me) plus an UltraBay battery. A terrible combination. The UltraBay battery lost rated capacity at a horrible rate because it was always getting fully discharged (certain death for Li-Ion batteries). Within the year, the UltraBay battery was only providing about an hour of extra run time.

Whatever you do, I recommend that you put the following in the comments section of your online order:
"The Li-Ion battery must have been manufactured within the previous 30 days. I will return any battery that is more than 30 days old".

Li-Ion batteries start degrading as soon as they're manufactured--whether they're used or not. So getting as new a battery as possible is key.

Hope this helps,
.../j

[cmp]

This is extremely helpful. Thanks so much.

[underclocker]

Well...I find the 9 cell to be very heavy and it throws off the balance of T-series machines (and R-series, too). What I mean by this is that with a 6 cell battery, the machine feels well balanced, front to back and side to side, when opened and in use. Like on your lap.

With a 9 cell, much more weight is in back and with the LCD open, the machine feels tippy toward the back, like it can flip right out of your hands. Plus the 9 cell makes the TP deeper and heavier.

Also, the newer model 6 cells, released when the T43 came out, have longer life than the original 6 cells. 4+ hours is what I get for normal use - email, Internet, word processing, etc.

If you need 6 hours life, 9 cell is right. If 4 hours is OK, then the 6 cell is better, IMHO.

[ParzanM]

Whatever you do, I recommend that you put the following in the comments section of your online order:
"The Li-Ion battery must have been manufactured within the previous 30 days. I will return any battery that is more than 30 days old".

1)Will this make a significant difference if the battery is more than 30days old? are we talking a few minutes(10-15min) on battery life or we talking 30-45min? also how would you check the manufactured date?

2)also can you swap a ultrabay battery for the cd-rw while the thinkpad is on or do you have to power down?

thanks
Parzan
Ps. im using NHC and uninstalled the ibm power maximiser

[jch]

1)Will this make a significant difference if the battery is more than 30days old? are we talking a few minutes(10-15min) on battery life or we talking 30-45min? also how would you check the manufactured date?

In IBM's Power Manager, there is a tab under "Battery Information" which shows the Manufacture date and the first-used date.

It will also state a Manufacture date on the battery's cardboard box. However, on the battery I just bought, the battery was in a *newer* cardboard box(!). The box said Aug 2006 whereas the battery itself (via Power Manager) said July 2006.

Having owned several Li-Ion powered devices (and having made the mistake of storing them fully-charged), I have learned that *how* the battery is stored matters a lot. If it's less than 30 days old, then it'll be in good condition regardless.

However, if it's been stored fully-charged (or completely discharged), the battery will "passivate", creating a permanent loss in capacity. Passivation is the reason that Li-Ion batteries need to be replaced every few years.

A Li-Ion battery that is stored fully charged (or discharged) for 6 months could lose as much as 20% of its full-charge capacity. Capacity that can never be reclaimed.

Running a Li-Ion battery too low (say, 10%, depending on how evenly-matched each cell within it is) will also cause passivation on the weakest cells.

A poorly-stored 9-cell Li-Ion battery will have less capacity than a well-looked-after 6-cell.

2)also can you swap a ultrabay battery for the cd-rw while the thinkpad is on or do you have to power down?

Yes, you can change it on-the-fly. The problem with the UltraBay batteries is that they are kept at either 100% charge, or run down to 0% -- both worst-case scenarios for the long-term life of the battery.

A 6-cell battery does feel better than a 9-cell in a T41 for sure, but in a year's time when its capacity is down to 70% of original, you'll find your usage patterns changing to compensate for the now not-so-great battery life.

If you start with a 9-cell, you'll have a heavier (back-heavy) laptop but (if you're like me) you'll find the battery life ample to last you several years, even when it degrades in capacity.

My two cents. I'm sure others will differ.

Hope this helps,
.../j