Dear Brother,
I think it is not just like battery and clock. It is one of examples. Because a battery can be removed from a clock and inserted back to the same clock at any time. But it is not possible in soul-body example. For a given clock, a battery can be recharged again and used more times. But here it is opposite. The soul is recharged after 84 births (for those who take maximum births). All batteries and clocks can be identical. But in BK philosophy, part of every individual soul is different. And also the name and features of the body are different. The battery can be used for different purposes. But here human soul and animal souls are different.
And much more differences can come.
This is the difficulty in giving The Knowledge exactly. That is why perhaps, it is said, knowledge sits just in pure intellect. Others will just get confusion by so many examples and controversies.