On Mon, 29 Jan 2007 08:26:50 -0500, J. Clarke wrote:
> The Eneloops are designed for low self-discharge. However I have seen
> no evidence that they have "*much* lower self-discharge rates than
> Li-Ion". Than conventional NiMH, yes, but ASAAR is the only person
> I've ever seen assert that they were better than Li ion in that
> regard.
I'm not the only one. Several Li-Ion manufacturers implicitly
agree. One states on the accompanying instructions that to prevent
damage to their Li-Ion batteries they should be charged at least
once every 3 months. They do say that this periodic charge need
only be for a few minutes. The other manufacturer ups the period to
once every 6 months. There have also been several users here who
have posted messages complaining about their dead Li-Ion batteries
that could no longer be charged even though they hadn't received
very much use. When asked, they admitted that their cameras had
been stored in a drawer for many months without being charged.
Contrast that with Eneloops (and the other brands) that leave the
factory fully charged, and have "sell by" dates and information on
the package indicating that the batteries can sit in a warehouse or
on a store shelf for two years, and at that point they'll not only
*not* have died, but will still be usable out of the package,
retaining about 85% of the initial charge.
Losing 15% of their charge over 24 months is clearly an extremely
low self-discharge rate, well below 1% per month. Li-Ion also has a
low self-discharge rate, and I've seen some claims but don't recall
what they were, but I'm fairly sure that they were much greater than
1% per month, probably somewhere in the 2% to 4% range. It's also
hard to pin down Li-Ion self-discharge rates since unlike NiMH
technology, Li-Ion is apparently a generic label covering a number
of different Li-Ion chemistries. Some probably have better
discharge rates than others, better low temperature performance than
others, etc. But of all of these types, I've never seen any that,
like the new Eneloop type batteries, have been sold pre-charged. If
they could be, without dying on a store's shelf, they would be. But
every one I've seen so far requires a long initial charge before
being used for the first time.
> but ASAAR is the only person I've ever seen assert . . .
And not for the first time either. I believe that I was the first
(about 2 years ago) to assert in this ng that alkaline batteries
weren't virtually worthless for use in digital cameras. The general
consensus was that NiMH batteries were a "must", and even they
didn't provide exceptionally long life. But after hearing all of
the battery horror stories and noting that my camera's manual
predicted very good battery life from alkalines and double that life
from NiMH cells, I decided to duplicate the CIPA test procedure
specified in the manual, using the alkaline AA batteries that were
packaged with the camera. I found that they were good for slightly
more than the estimated 200 shots, and what's more, that by not
using the flash any more, the batteries were good for more than
another 400 flash-free shots. For nearly the next year or so many
people routinely continued to insist that alkaline batteries were
worthless, not realizing that this was no longer true for some of
the new cameras being sold. I don't see much of this any more.
>> Stay informed about: Olympus SP-550 UZ: 18x ultra zoom 
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