[robot prom]

i'm looking on eBay to pick up another battery for my G4/550 Powerbook, and there's a lot of batteries on there with a variety of model numbers. The model number of the battery that came with my PB is M6091. There's also M8511, A1012 and M8244G/B.

Are the different model numbers interchangeable? Is one model number better than the others?

[robot prom]

anyone know an answer?

[N.N.]

There have been three different, but interchangeable battery models for the PowerBook G4 Titanium from Apple:

M6091 (1st generation TiBook) - 50 Wh
M8511 (2nd and 3rd generation) - 55.3 Wh
A1012 (4th generation) - 61 Wh

M8244G/B is just the order number and does not implicitly tell the capacity, but both order number and model number are printed on the cardboard box, whereas only the model number is printed on the battery itself.

If you buy a new or used battery, check its serial number if possible. As with all Apple products, the first digit in it tells the year and the second and third tell the week of its manufacture.