Need a new Battery

[nigratruo]

Hi,

I have a T61p and a few other T61 15.4 inch before that and have gone through many batteries in its 10 years live.
I bought a 9 cell extended battery on Amazon a year ago and is has declined in capacity steadily, at which point now it is hardly usable and the OS considers it as broken (less than 40% capacity left)
Is there a way to tell good batteries from crappy ones? Is one year use all I will get out of any "new" battery? Are there some that give you warranty to make sure they last longer?
Which types do I have to look for for this type of 15.4 inch T61? There are seemingly a million different types around and it is hard to know which one will fit and which ones will not.
Do the 14 inch T61 types have different batteries or the same ones?
These questions always concern the extended 9 cell type.

[theterminator93]

Your best bet is to keep an eye out for used Panasonic cells here or on eBay. They last the longest in terms of cycles and capacity degradation over time/cycles.

The Panasonic 9 cell batteries I have in my T601F and the wife's T61p are both coming up on 10 years old now, and they both hold 85-90% what they did when they were brand new - with several hundred cycles on them.

The 15.4" widescreen T61 uses the same battery as the T60 (all flavors) and the T500. The 14.1" widescreen T61 and T400 battery will not work.

[nigratruo]

Thanks for the tip, any idea how I can find a panasonic cell on ebay? I have tried to filter for it, but had no success so far.
Does anybody have a product number that is a battery with a panasonic cell so I can look for it?

[ajkula66]

92P1133 is one of the FRUs for a 9-cell Panasonic.

I'd make sure to confirm with the seller that is the *exact* FRU of the battery that you're getting.

[wujstefan]

Why ebay?
Looky here, I have only one new Panasonic left, all the rest are Sanyo.

viewtopic.php?f=11&t=125591

EDIT:
FRU on the labels says 42T4620

[RealBlackStuff]

Panasonic 9-cell: FRU=92P1133, ASM=92P1134 (cells made in China, assembled in China)
Panasonic 9-cell: FRU=42T4620, ASM=92P1134 (cells made in Japan, assembled in China), THE best!!!!
They DO have the same ASM-number.

[madicetea]

Why ebay?
Looky here, I have only one new Panasonic left, all the rest are Sanyo.

viewtopic.php?f=11&t=125591

EDIT:
FRU on the labels says 42T4620

This is curious. I have a 41++ that I paid good money for when I got it here in Japan (it was one of the last unopened box batteries complete with the seal intact). It's SANYO cell, but performs wonderfully (only 14% wear in one year) and the FRU is also 42T4620. I wonder if Panasonic and Sanyo cells were interchangeable designation.

Also have a troublesome (but not totally dead) Sanyo (?) 4-cell and a 65% health 4-cell, both Panasonic. So perhaps there is just very little consistency.

[RealBlackStuff]

As a matter of fact, Panasonic bought up Sanyo for its batteries in 2009 or 2010
https://www.cnet.com/news/panasonic-fin ... -of-sanyo/

[madicetea]

Oh, that is quite interesting news.

Thank you.