Aren't rechargeables for high current applications?

On Fri, 05 Dec 2008 06:05:52 GMT, John Doe
wrote:

"Phil Allison" wrote:
"John Doe"

( snip load of top posted, puerile drivel)

Appears to be a same dialect. Okay, so I see Phil is obsessed with
Sylvia in the Australian legal group. So maybe Phil and Rod are the
same, or brothers, or maybe bedfellows.

** Anyone as colossally stupid as YOU pal, needs to develop a
thicker hide.

Do you have a Crocodile Dundee complex, Phil?

**** off - fool.

Are you in a movie, Phil?

You should tale pity on Phil.

His sheepfriend just chucked him!



















..... Phil



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From: "Phil Allison"
Newsgroups: rec.photo.digital,sci.electronics.design
Subject: Aren't rechargeables for high current applications?
Date: Fri, 5 Dec 2008 16:14:50 +1100
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On Thu, 4 Dec 2008 18:18:10 -0800, BobW wrote:

Low leakage NiMH batteries are pretty cheap now, on sale they're around
$1.50, so they're only about 2x the price of name brand AA alkalines at
Costco.

Leave it to SMS, the so-called battery "expert" to inflate prices
of the AA batteries that he loathes, when he somehow always can find
much lower Li-Ion prices than the rest of us can. Name brand AA
alkalines, such as those from Sanyo, Panasonic, RayOVac, Maxell and
others can often be found in larger camera & electronic stores,
supermarkets and Rite-Aid type stores for prices ranging from 20 to
25 cents each, not the 75 cents claimed by the "expert". Some of
these stores have permanently low battery prices. With others you
wait for sales (Pathmark == frequent, Rite-Aid == infrequent). If
you don't plan ahead and only buy 2AA or 4AA blister packed
alkalines as needed, then yes, you pay higher battery prices.


I really like these so-called hybrid NiMH batteries. I use the Hybrio brand.

Certainly for cameras, the alkalines are terrible due to the high current
demands. It's nice being able to grab a camera that I haven't used for
months and have it work. I could never do that with conventional NiMH
batteries. I'm even using them in my flashlights now that I know they won't
be dead after sitting for a long time.

Low self-discharge NiMH cells such as Hybrios, Hybrids, Eneloops,
etc. are excellent and the best types for many purposes, but not for
all. You can't make that generic statement, that alkalines are
terrible for use in cameras because there's a tremendous difference
in the power demands of different cameras. The worst possible case
is when shots are taken with the flash and the LCD is used. As you
suspect, some cameras do very poorly when powered by alkalines, but
many (in cameras from Canon, Fuji, Nikon, etc.) can provide hundreds
of shots from a set of alkalines even when the flash is used, up to
and beyond 1,500 shots when the flash is not used.

Bogus battery information can also color your expectations. One
example is Canon's A570IS camera. Canon's manual states that it
should be able to get 120 shots (CIPA test, using flash and LCD) and
400 shots (no flash and using viewfinder) from a pair of AA alkaline
cells. I tested that camera and got even more shots than Canon
claimed. SMS on the other hand frequently stated in this newsgroup
that the A570IS did worse than this by an order of magnitude. Even
today his battery data website claims :

I lent an AA powered camera (Canon A570IS) to a relative that tried
to use alkaline AA batteries while on a cruise. She reported getting
about ten pictures per set of batteries. When I inquired if this was
normal on rec.photo.digital I got a slew of responses and every one of
them reported similar results with alkaline batteries.

Whether bogus information or a blatant lie, the responses weren't
similar and unanimous. IIRC, he also stated that she then purchased
new alkalines and got the same terrible battery life. This couldn't
happen unless that particular camera was defective, and it's very
unlikely that it was, since he said he'd check the camera when it
was returned, but he never reported any findings. And despite the
above quote, which if true would indicate an unacceptable camera
with possibly the worst battery performance ever, SMS has since
recommended the A570IS in this newsgroup many times.

As you say, the hybrid type NiMH batteries are good choices for
flashlights, but with two caveats. The first is that if the
flashlight user waits for the light to dim before recharging the
batteries, there's a chance that one or more cells might become
reverse-cell damaged. The more cells that are used, the greater the
possibility. Two cell flashlights should be safe, unless they're
the more expensive types using voltage regulators. Flashlights
using four or more cells provide the greatest risk. The second is
that for emergency use, alkalines provide a good warning that the
batteries need to be replaced because of their slow, gradual voltage
decline. When NiMH batteries become depleted, the light falloff can
be extremely rapid, giving you little time to find a set of
replacement batteries. For most people using flashlights around the
home or auto though, this shouldn't be a significant concern.

ASAAR wrote:
[]
Low self-discharge NiMH cells such as Hybrios, Hybrids, Eneloops,
etc. are excellent and the best types for many purposes, but not for
all. You can't make that generic statement, that alkalines are
terrible for use in cameras because there's a tremendous difference
in the power demands of different cameras. The worst possible case
is when shots are taken with the flash and the LCD is used. As you
suspect, some cameras do very poorly when powered by alkalines, but
many (in cameras from Canon, Fuji, Nikon, etc.) can provide hundreds
of shots from a set of alkalines even when the flash is used, up to
and beyond 1,500 shots when the flash is not used.

How well do 2000mAh Eneloops stand up to fast charging? I have a
so-called 1 hour charger which has a stated charge current of 2A, and
negative delta-V protection.

David

On Fri, 05 Dec 2008 13:55:04 GMT, David J Taylor wrote:

Low self-discharge NiMH cells such as Hybrios, Hybrids, Eneloops,
etc. are excellent and the best types for many purposes, but not for
all. You can't make that generic statement, that alkalines are
terrible for use in cameras because there's a tremendous difference
in the power demands of different cameras. The worst possible case
is when shots are taken with the flash and the LCD is used. As you
suspect, some cameras do very poorly when powered by alkalines, but
many (in cameras from Canon, Fuji, Nikon, etc.) can provide hundreds
of shots from a set of alkalines even when the flash is used, up to
and beyond 1,500 shots when the flash is not used.

How well do 2000mAh Eneloops stand up to fast charging? I have a
so-called 1 hour charger which has a stated charge current of 2A, and
negative delta-V protection.

I can't say because I haven't used my fast (30 minute & 60 minute,
neg. delta-V) chargers with Eneloops and other low self-discharge
NiMH cells. My guess, though, is that they'll do at least as well
as standard NiMH cells and possibly better. This is based on two
reasons. First, when I first purchased them, the manufacturer's
literature stated that they could be charged with any "well
designed" battery charger, and there was no indication that slower
chargers would be preferred.

The second reason is based on what a number of photographers in
DPReview's Lighting Technique forum have said about using Eneloops
in hot shoe mounted flash units. They report that despite the lower
capacity (2,000 mAh vs 2,700mAh), Eneloops provide as many flashes
per charge as the higher capacity standard NiMH cells. They've
thought that the reason is that the lower internal resistance
results in less energy wasted in battery heat losses, and have also
noted that this allows the flashes to be used more rapidly without
causing the flash units to shut down. This lower internal
resistance may also reduce the internal heating of Eneloops while
they're being charged. This is only conjecture, as I haven't heard
of anyone testing this hypothesis.

So far there I haven't used quick chargers with my Eneloops and
Hybrids, but if there was a need for it, I'd have no qualms about
doing so.

On Fri, 05 Dec 2008 01:33:23 +0000, John Doe wrote:

Since the worth of a NiMH rechargeable battery is determined by how many
alkalines you avoid buying and disposing of, what's the point of low
leakage current NiMHs?

In other words. Why would you care if the NiMH still has a charge after
one year? Doesn't that negate the value of being able to recharge the
battery hundreds of times? Why not use an alkaline if it needs to last for
one year?

Or, is ordinary/current NiMH leakage current problematic even for high
current uses, and battery makers are trying to correct that?

FWIW, I'll never waste my money on NiMH's again. I bought a "smart"
charger that came with 4 NiMH's once, and was kind of impressed.
Unfortunately, my camera (a Fuji) has a terrible current drain when
it's off, presumably to keep the RTC up. So, I'd pick up the cam,
turn it on, and the NiMHs were dead. So, I'd get the next pair off
its shelf, slap the discharged pair in the charger, and be on my
merry way. Then, freshly charged, bu thaving sat for a couple of
weeks, they were dead. Finally one day, I had no charged NiMHs -
I "charged" 4 of them, and NONE OF THEM would make the camera go.

I mean, pulled them right out of the charger, put them in the camera, and
nothing, like their shelf life was zero.

So I trashed the whole lot, bought a couple of AA alkalines, and
they're still going after almost a year.

BTW, I've never heard of alkalines having a "high internal resistance" -
IME, they're almost as hot as Nicads.

Good Luck!
Rich

writes:

On Dec 5, 8:41 am, ASAAR wrote:

Whether bogus information or a blatant lie, the responses weren't
similar and unanimous. IIRC, he also stated that she then purchased
new alkalines and got the same terrible battery life. This couldn't
happen unless that particular camera was defective, and it's very
unlikely that it was, since he said he'd check the camera when it
was returned, but he never reported any findings. And despite the
above quote, which if true would indicate an unacceptable camera
with possibly the worst battery performance ever, SMS has since
recommended the A570IS in this newsgroup many times.

There are cheap Chinese knock-off batteries that go to great lengths
to look a lot like Duracells or Energizers.
At a quick glance, they look the same. However, even new, they can't
even get a camera to turn on. Internal resistance is that high.
Probably bottom of the barrel carbon/zinc batteries masquerading as
alkalines.

I gather a lot of the D cells have AA's inside.

--

John Devereux

ASAAR wrote:
[]
So far there I haven't used quick chargers with my Eneloops and
Hybrids, but if there was a need for it, I'd have no qualms about
doing so.

Thanks for that - your observation and conclusions make sense to me. I
have become sufficiently dissatisfied with the poor shelf-life on
conventional Ni-MH cells that I have located a UK supplier (none of the
normal places I use had them, but Amazon did), and ordered a set to try.
Both of the devices where I might use the cells are very intermittent use
devices, so long charge retention is important.

I'll keep a careful finger on the temperature at the first charge,
providing the cells don't explode first! I was unable to locate a
manufacturer's data sheet with recommended charge rates, and that was
annoying.

Cheers,
David

John Devereux wrote:
[]
I gather a lot of the D cells have AA's inside.

I thought that most D Ni-MH cells were made like that?
At least, all I've ever seen.
Reputable makes.

David

Rich Grise wrote:
On Fri, 05 Dec 2008 01:33:23 +0000, John Doe wrote:
Since the worth of a NiMH rechargeable battery is determined by how many
alkalines you avoid buying and disposing of, what's the point of low
leakage current NiMHs?

In other words. Why would you care if the NiMH still has a charge after
one year? Doesn't that negate the value of being able to recharge the
battery hundreds of times? Why not use an alkaline if it needs to last for
one year?

Or, is ordinary/current NiMH leakage current problematic even for high
current uses, and battery makers are trying to correct that?

FWIW, I'll never waste my money on NiMH's again. I bought a "smart"
charger that came with 4 NiMH's once, and was kind of impressed.
Unfortunately, my camera (a Fuji) has a terrible current drain when
it's off, presumably to keep the RTC up. So, I'd pick up the cam,
turn it on, and the NiMHs were dead. So, I'd get the next pair off
its shelf, slap the discharged pair in the charger, and be on my
merry way. Then, freshly charged, bu thaving sat for a couple of
weeks, they were dead. Finally one day, I had no charged NiMHs -
I "charged" 4 of them, and NONE OF THEM would make the camera go.

I mean, pulled them right out of the charger, put them in the camera, and
nothing, like their shelf life was zero.

So I trashed the whole lot, bought a couple of AA alkalines, and
they're still going after almost a year.

BTW, I've never heard of alkalines having a "high internal resistance" -
IME, they're almost as hot as Nicads.

Good Luck!
Rich

Most people seem to be aware of alkalines having a higher internal
resistance then either NiMH or NiCD.
Since literally millions of people are happily using NiMH in their
cameras, it might occur to you that you have a problem with the camera.
My guess would be it's unduly sensitive to the lower voltage of NiMH,
but one would need to do further testing.
Dave Cohen

Rich Grise wrote:
On Fri, 05 Dec 2008 01:33:23 +0000, John Doe wrote:

Since the worth of a NiMH rechargeable battery is determined by how
many alkalines you avoid buying and disposing of, what's the point
of low leakage current NiMHs?

In other words. Why would you care if the NiMH still has a charge
after one year? Doesn't that negate the value of being able to
recharge the battery hundreds of times? Why not use an alkaline if
it needs to last for one year?

Or, is ordinary/current NiMH leakage current problematic even for
high current uses, and battery makers are trying to correct that?

FWIW, I'll never waste my money on NiMH's again. I bought a "smart"
charger that came with 4 NiMH's once, and was kind of impressed.
Unfortunately, my camera (a Fuji) has a terrible current drain when
it's off, presumably to keep the RTC up. So, I'd pick up the cam,
turn it on, and the NiMHs were dead. So, I'd get the next pair off
its shelf, slap the discharged pair in the charger, and be on my
merry way. Then, freshly charged, bu thaving sat for a couple of
weeks, they were dead. Finally one day, I had no charged NiMHs -
I "charged" 4 of them, and NONE OF THEM would make the camera go.

I mean, pulled them right out of the charger, put them in the
camera,
and nothing, like their shelf life was zero.

Sounds to me like you have a crap charger.

So I trashed the whole lot, bought a couple of AA alkalines, and
they're still going after almost a year.

BTW, I've never heard of alkalines having a "high internal
resistance" - IME, they're almost as hot as Nicads.

Good Luck!
Rich

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)