X61 battery p/n

[karotlopj]

There are two batteries available for the X61 - a small one and a large one.

Does anyone know of any comparison article about them?

Also I'm trying to find part numbers for both to make sure I get the right one.

One advert I've seen shows an item as being compatible with

40Y6999 40Y7001 40Y7003 42T4505 42T4506 42T5224 42T5247 42T5266 92P1163 92P1164 92P116 92P116 7 92P1168

Looking through the HMM for the X61, it isn't easy to lookup which I need.

[axur-delmeria]

After looking at the FRU listing at the end of the HMM...

Avoid the batteries listed as Battery 4-cell Li-Ion (Prismatic) because these are only compatible with the X60s and X61s-- these are the slim variants of the X60/61 family, with a battery slot that's slightly wider than the regular model. Regular X61 batteries will fit the slim models with a spacer that's usually included, but the prismatic batteries are physically wider and will only fit the slim models as a result.

The ones listed as Battery 4-cell Li-Ion (2.6AH cylindrical) and Battery 8-cell Li-Ion (5.2AH cylindrical) are compatible with the X61. The 8-cell sticks out from the back, and provide around 3.5 hours of runtime, the 4-cell gives half of that. Knockoff batteries give less, around 3 hours for the 8-cell (based on personal experience).