I use 2.5kma AA Ni-MH rechargable battery for my xb360. it lasts longer than the M$ ori Ni-MH rechargable battery(1 full week - 3 hrs per day before the power run out).

about using the Ni-MH rechargable battery... Ni-MH battery has "memory" effects... be sure to fully discharge it to zero juice b4 recharge it if u want to it store full power.