Re: Li ion batteries



ASAAR wrote:

On 16 May 2006 17:05:09 -0700, y_p_w wrote:


At the
rate many casual shooter take pictures, that set of batteries could
easily last a year or two . . . or more. And alkalines don't have
any appreciable self discharge. I've found that alkalines retain an
appreciable charge even after their expiration date, and most of the
currently sold alkalines that I've seen have expiration dates
ranging from 2011 to 2013.

However - they will leak if left in a device too long. I've seen it
happen with the resulting damage to to the device. It's not a big
issue with constant low-drain devices like wall clocks.


That's possible, even likely with poorly designed cameras. But
for the most part very unlikely. The "poor design" would be a
camera that uses more than the minimal amount of power to keep the
camera's clock/calendar running. The old Powershots, for instance,
used a lithium button cell to maintain the time and camera data, and
whether the main battery was installed or not, they had a life of at
least 3 years. But the proprietary NiMH battery pack would run down
very quickly if left in the camera, far faster than the normal self
discharge rate.

My PowerShot S1 IS has a CR1220, located right next to the
(AA) battery door hinge. My old S200 didn't have a backup.



Alkalines have their place. However - even something like a
Canon A-series can take up to 2-4 times the number of shots
on a charged set of NiMH AAs. My particular camera (PowerShot
S1 IS) eats alkalines for lunch. I tried it out the first time with a
fresh set of alkalines and it was asking for new batteries after
about 70 pictures. I've been able to take 400+ shots on a
single charge of NiMH AAs. NiMH AAs also outperform alkaline
in flash recharging. I could have easily gone through $100 of
alkalines at $1 for 4 in the time I've used two $10 pair of NiMH
batteries. They're still going strong after two years, although I've
moved them to a different device.


I can't be certain, but I think that others here have noted that
the S2 IS is much less power hungry than the S1 IS. It should only
be older A-series cameras that get 4x the battery life from NiMH
cells. The ones sold for the last year or two are much better,
using much less power, so alkalines last much longer relative to
NiMH. I think that Canon rates them about 1/2 the life of NiMH when
using the CIPA test procedure that stresses the batteries (lots of
zooming, use of flash, LCD, etc.). There's no doubt that if anyone
takes lots of pictures, especially when many of them use the flash,
that rechargeable batteries become very practical. Additionally,
since they get so much use, there isn't enough time for self
discharge to become annoying. It might be worth verifying whether
the S2 or S3 IS really gets much more life from its batteries. If
so, it might make it worth upgrading your S1 earlier than you might
have considered. :)

I just ordered an S3 IS on Sunday.

There's also a very good chance of alkaline batteries leaking
in long-term storage. I like alkalines for wall clocks and remote
controls. It's nice having them as backups.


Well, NiMH are poor choices in clocks and remotes, but mainly from
a convenience standpoint. Even though I've found that the alkalines
in my TV and VCR's frequently used remotes lasts quite long (several
years), they can't be forgotten about, since even though generic
remotes can be bought for as little as $5, if leakage damages one of
my Sony's remotes, a cheap replacement isn't possible. When a
button on a VCR remote broke, several years ago, I found that Sony's
replacement price was $70 or $75, only a few dollars less than I'd
be able to pay to get a new Sony remote from a local store, one that
also happened to include a free VCR along with the remote. :)

In general I've found that aftermarket remotes work quite
well. Sony even make a few which (of course) are set at
the factory with Sony device codes.

Rechargeables in flashlights do run a risk of voltage reversal.


Only if you leave them powered on and forget to return to turn
them off. If they use 2 or 3 cells, within seconds of the first
cell becoming discharged, the light output will drop drastically.
There might not even be enough voltage left to get a feeble glow
from the bulb's filament. But you're right. If you turn your back
on a flashlight for several minutes you might return to find a
damaged cell.

Sometimes I'll just leave a flashlight on a table. I was
trying to cycle an old set of NiCads and forgot about it
when one of the cells reversed. Probably should have just
used my Maha charger with the condition feature.

I've just about given up on using traditional flashlights, as I
have several that use LEDs that are far superior. The ones that
have modest light output get about 20 times greater life. Other
lights that power the LEDs with AAA batteries last as long as larger
flashlights that use D cells, even though their light output is
greater, the brightness doesn't drop off nearly as rapidly, the
light distribution is much more even, and the LED color is much
"whiter" for most of the battery's life. Add to that, LEDs don't
burn out like bulbs, which are also easily damaged by shock.

I thought of LEDs, but I don't think they're practical
for all applications yet. LEDs seem to be taking over
the bicycle headlamp world, but they're still not as
bright as older halogen lamps. The real state of the
art in bicycle headlamps are (I kid you not) rechargeable
HID setups.

<http://www.cygolite.com/light/products/1zForceNiMH.htm>
.

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