Frank Gruendel wrote:
>
> > Now, NiMH batteries (and other types of rechargables) do have a
> > fairly constant, but slight, capacity loss over the lifetime of the
> > battery. More recent NiMH batteries will lose 10-15% of their
> > capacity over their lifetime.
>
> This might be a stupid question, but why has a NiMH battery that has
> lost only 10% of its capacity reached the end of its lifetime? Especially
> since most batts have MORE than the specified capacity when they
> are new??
Well, from my understanding, NiMH can take between 300 and 500 "recharge
cycles" -- at least, that is what most manufacturers say. So, at some point,
they will stop taking a good charge after so many cycles. It is at that point
-- when it begins to stop taking a charge at all and keeping it -- that it has
reached the end of its lifetime.
So -- there is the lifetime thing. Now, over that lifetime, at a fairly
constant rate, they lose 10-15% of their _original_ capacity. So, a battery
on, say, it's 400th recharge, may have 10% less capacity than it did on it's
first recharge -- but otherwise still work fine. But, on it's, say, 600th
recharge, when it would have 15% less capacity if it worked, may stop taking a
charge completely (or, at least, not hold a charge at a significantly useful
level). At that point, the fact that it would be 15% less capacity than it
originally had becomes a moot point, since it isn't taking a charge anyhow.
That make more sense? Again, I'm no NiMH expert -- that just what I've read
after my searching.
- John...
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