W520 extended battery P/N

[u666sa]

The time has come to buy a new battery, may laptop is two years old in this upcoming June, battery life has dropped to about 1:30 hrs.

I do have a 9 cell battery, but I think there is a bigger battery, like 12 cell or something similar, with its butt sticking up to the rear and up. What is the P/N for such battery?

[jcvjcvjcvjcv]

If there is, it's not from Lenovo itself.

Lenovo has the 6-cell 70+, the 9-cell 70++ and the 9-cell slice battery 28++

The ones that go out of the rear and up are 9 cell batteries for smaller Thinkpads, like the 9-cell on a 14"W T61 (released way later)

[Brad]

I would look for another 9 cell. Specifically the Panasonic 9 cell. FRU 42T4801. As with most ThinkPad batteries those using Panasonic cells seem to last longer and work better than all others.

My .01c.

Brad

[jcvjcvjcvjcv]

If I'm not mistaken, that is a partnumber of the older 55++; all the batteries got replaced with new models that are compatible with "rapid charge". The older ones won't charge in newer systems. You'll probably only find old stock with that number.

My 55++ from LGC is now 2 years old; I use it since August 2012... it has 138 cycles, it spent more than half it's life in Maximum Lifespan mode... and it's down to 74.8 Wh, down from 93.6 (design capacity).
My 7-cell T61 battery didn't lose that much in 5 years..