From: ASAAR on
On Tue, 11 Sep 2007 18:38:11 -0700, SMS wrote:

>>> I don't know where he got the idea that using the adapter would
>>> damage the cells. Certainly there are C & D cell sized NiMH
>>> batteries that are used in non-digital devices without any issues.
>>> It's probably just another thing he made up.

>> It seems to me that C and D cell adapters would be a good application
>> only on those devices that shut off, as you said, and on the LED upgrade
>> add-ons for some flashlights you can now buy. Replacing an incandescent
>> bulb with LED, and D cells with AA cells would be feasible.
>
> Well maybe for kid's toys it's a legitimate concern to worry about
> polarity reversal caused by unintentionally leaving a toy on, but for
> adults that are more responsible about turning things off when done it's
> not a big issue. I do mention about the cell reversal issue on the web
> site, and warn about not draining cells all the way down.

And once again you've proved yourself to be a windbag that gets it
wrong, makes accusations, is proven wrong, but never apologizes.
Maybe you could correct some more of your web site's misinformation
by stating that AA batteries are much better than you ever realized,
because one of their problems that you harp on so much is really not
the big issue you've previously made it out to be, for responsible
adults that is. It's funny that you already knew about the
potential for cell reversal, yet still publicly stated that my
warning was for "just another thing he made up." You, SMS, are the
lowest of the low. And like O.J., you know it but are doomed to
pretend otherwise in your fantasyland.

From: Thomas T. Veldhouse on
ASAAR <caught(a)22.com> wrote:
>
> The only other time you accused me of making something up I proved
> that you were wrong. You know that I did, and you repeat this lie
> because, well, that's the kind of guy you are. If you can't figure
> out how NiMH batteries can be damaged, you're either not very
> bright, or you're not a very knowledgeable battery "expert". Damage
> to NiMH batteries can occur with digital devices (as I've found with
> several Sony radios that use 3 and 4 cells), but damage is far more
> likely when used to power non-digital devices. You really should
> stop boasting about your battery knowledge if you don't know or
> can't figure out how the damage can occur.
>

If you are referring to polarity reversal, it has nothing to do with whether a
device is digital or not. Just that it has the capability to shut down when
the voltage drops to a given level, which gets increasingly difficult to avoid
polarity reversal if there are several batteries in series. An analog device
that runs its batteries in parallel and then steps up the voltage to operating
levels and knows to shutdown when voltage drops below 1.0V (can be measured
analog) across the cells would do fine. In practice, a digital device is more
likely to have this capability, but it is not an inherant trait of either
digital or analog devices.

--
Thomas T. Veldhouse

We have more to fear from the bungling of the incompetent than from the
machinations of the wicked.

From: SMS on
Thomas T. Veldhouse wrote:

> If you are referring to polarity reversal, it has nothing to do with whether a
> device is digital or not. Just that it has the capability to shut down when
> the voltage drops to a given level, which gets increasingly difficult to avoid
> polarity reversal if there are several batteries in series. An analog device
> that runs its batteries in parallel and then steps up the voltage to operating
> levels and knows to shutdown when voltage drops below 1.0V (can be measured
> analog) across the cells would do fine. In practice, a digital device is more
> likely to have this capability, but it is not an inherant trait of either
> digital or analog devices.

It's interesting to see what GP claims about polarity reversal at
"http://www.nimhbattery.com/gp70aaahc-u4.htm" where it states:

"Polarity Reversal Protection - Built In chemical protection against
polarity reversal or over discharge."

Are they just blowing smoke, or do they really have some sort of
protection that other NiMH batteries lack?

In any case, while you're correct that it's not an inherent trait of the
device type, it is true that with devices like flashlights you want to
be a bit more careful to not accidentally leave the device on and drain
the batteries completely to 0%. ASAAR overstated the issue of course,
but there was at least a grain of truth in what he said.

With ni-cads you could zap away internal shorts and also reverse
polarity reversal. This is not the case with NiMH.
From: Allen on
Thomas T. Veldhouse wrote:
> Allen <allen(a)nothere.net> wrote:
>> In Austin (TX, not MN) the Costco Eneloops are packaged in a blue
>> plastic case, which contains 12 AA, 3 or 4 AAA, a charger, and adapters
>> to use AAs in C and D cell devices, all for $26.99. I haven't bought any
>> because I bought 8 Rayovacs early on, and don't need any more. I have
>> doubts about the worth of the C and D adapters.
>
> Don't have doubts. We have a mid-priced elipitical trainer that uses D
> batteries for several mechanical and control functions and the adapters work
> great in it with the 2100mAh Rayovac Hybrids in them. I use a C adapter in a
> a large clock and have no trouble so far. We also have a few cheap
> flashlights I have considered putting D adapters into, but haven't desired to
> put batteries in a flashlight that cost more than the flashlight itself ;-)
>
Thanks. I may have to break down and try them.
Allen
From: ASAAR on
On Wed, 12 Sep 2007 13:05:03 GMT, Thomas T. Veldhouse wrote:

> If you are referring to polarity reversal, it has nothing to do with whether a
> device is digital or not. Just that it has the capability to shut down when
> the voltage drops to a given level, which gets increasingly difficult to avoid
> polarity reversal if there are several batteries in series.

I did NOT say that polarity reversal depends on whether a device
is digital or not. But I WILL say that it's much more likely to
occur when analog devices are used. Take radios for example. I
have yet to find (although there may be some) an analog radio that
won't play reasonably well with extremely low voltages. Voltages so
low that it's almost guaranteed to cause polarity reversal if care
isn't taken when using rechargeable NiCd or NiMH batteries. With
digital radios, many shut down at voltages high enough to prevent
voltage reversal. But a few (and I can name several Sony models if
you're interested) shut down at such a low voltage that damage is
pretty much guaranteed if you're not very careful.

An specific example where damage occurred was with a large
portable AM/FM/SW radio made by Sangean (sold under many other
names, including Roberts, Radio Shack, etc.) It also has a built-in
cassette player/recorder, and it destroyed a couple of my NiCd D
cells once when the batteries were depleted. This was one of the
devices that normally doesn't cause battery damage because the radio
section shuts down at a reasonably high battery voltage. The
problem here was that the radio *did* shut down. But I was also
using the recorder to tape a program off the air at the time. The
radio shut down, but the analog motor in the recorder didn't, as I
discovered when later examining the tape.


> An analog device that runs its batteries in parallel and then steps up
> the voltage to operating levels and knows to shutdown when voltage
> drops below 1.0V (can be measured analog) across the cells would do
> fine. In practice, a digital device is more likely to have this capability,
> but it is not an inherant trait of either digital or analog devices.

Uh, that may be interesting, but it has nothing to do with what I
was talking about. It was about using C and D cell battery
adapters. I haven't taken a survey, but I highly doubt that very
many devices that most people would be using with those adapters are
modern electronic devices that use voltage multiplier circuits.
Most are probably simple C or D cell flashlights, which can easily
damage the rechargeable cells. Well, not so much the flashlights,
since they'd tend to use only two cells and would be held in the
hand, making it hard to miss the light suddenly winking out. But
it's still possible even with flashlights that use 4 or more cells,
and I've recently seen a few that use 5 and 6 cells. Some of the
larger lanterns use 8, which is also the number of cells most often
used by boomboxes. And camp lanterns that use 4 or more cells and
stay on all night would be poor choices for rechargeable batteries,
unless they are of a very atypical, unusual design.