From: SMS on
Thomas T. Veldhouse wrote:

> Lower number of charge/discharge cycles is almost certainly incorrect unless
> you abuse the battery or run the batteries down each day every day of the
> year.

It all depends on usage. While both NiMH and Li-Ion batteries have
similar numbers of charge/discharge cycles, you have to charge NiMH
batteries more often. This is due to a) the high self-discharge, and b)
because they are usually lower capacity. On the other hand, you may
reach the time-limited lifetime of Li-Ion batteries well before you
reach the charge/discharge cycle limited lifetime.

> The incovenience of charging and swapping ... is not related to battery
> chemistry one bit; it is related to the usage pattern of the owner and is
> equally an issue for all battery chemistries.

It is related to the chemistry--indirectly. Two reasons. First, because
of the inherent dangers of using and charging unpackaged Li-Ion cells,
Li-Ion batteries are always packaged together in a pack that has
protection circuitry. By default you end up with a package that's easier
to swap. On the other hand, NiMH batteries are usually not packaged
together because there's an advantage of charging the cells
individually, and because no protection circuitry is needed. You could
design a system that discharged the pack in series but charged each cell
individually (this has been used on things like bicycle lights) but it
adds complexity and forces a proprietary pack.


> Lower reliablity of devices that use them is flat wrong. If a device is not
> capable of determining the batteries are delivering too low of power to
> prevent damage to the device, then NiMH and LiIon are equally unreliable in
> that device. If you use NiMH batteries in series in modern electronics, the
> risk is only to the battery and not to the device; and that risk being a
> complete discharge and polarity reversal; which is almost impossible with a
> two battery series or less.

It isn't the issue of too low of power, it's more a mechanical issue,
one that most of us have experienced on battery powered devices. Look at
the most commonly replaced part on AA powered digital cameras--it's the
spring contact battery cover. It has constant pressure against it, and
it's flimsy plastic. It's even worse if the the part that breaks is tabs
in the camera body rather than tabs on the replaceable battery door. On
cameras that use Li-Ion packs, the battery cover is usually not holding
the battery contacts against the contacts inside the camera.

Steve
http://batterydata.com
From: SMS on
Thomas T. Veldhouse wrote:

> I also saw you point out some of the inaccuracies in this very thread ... and
> you are correct, mostly silence.

Sorry, he was filtered long ago. If he's changed his ways I need to go
clear him out of my filter to see what he's saying now.
From: SMS on
Allen wrote:
> SMS wrote:
> Add to my post of a couple of minutes ago re identification of "experts":
> AND are not employed by a company that makes either type of battery.
> Allen

You can start here: "http://www.buchmann.ca/chap8-page1.asp"
From: ASAAR on
On Mon, 25 Jun 2007 16:09:51 -0700, SMS wrote:

>> I also saw you point out some of the inaccuracies in this very thread ... and
>> you are correct, mostly silence.
>
> Sorry, he was filtered long ago. If he's changed his ways I need to go
> clear him out of my filter to see what he's saying now.

Sorry, but when I pointed out your inaccuracies and misstatements,
well before you started using your filter, you never even attempted
to disprove any of my corrections. You simply ignored them and
continued spouting the same inaccurate facts. It's *you* that needs
to change your ways, but I'll be quite surprised if you do. We can
start with one of your repeated points of misinformation, that
cameras don't or can't have battery meters for NiMH cells due to
their supposedly flat discharge curve. There's plenty of evidence
that that is untrue, and I could repeat some of the reasons for you
if you're willing, but I'm amazed that a self-proclaimed "battery
expert" wouldn't know this already.

From: Ron Hunter on
SMS wrote:
> Thomas T. Veldhouse wrote:
>
>> Lower number of charge/discharge cycles is almost certainly incorrect
>> unless
>> you abuse the battery or run the batteries down each day every day of the
>> year.
>
> It all depends on usage. While both NiMH and Li-Ion batteries have
> similar numbers of charge/discharge cycles, you have to charge NiMH
> batteries more often. This is due to a) the high self-discharge, and b)
> because they are usually lower capacity. On the other hand, you may
> reach the time-limited lifetime of Li-Ion batteries well before you
> reach the charge/discharge cycle limited lifetime.
>
>> The incovenience of charging and swapping ... is not related to battery
>> chemistry one bit; it is related to the usage pattern of the owner and is
>> equally an issue for all battery chemistries.
>
> It is related to the chemistry--indirectly. Two reasons. First, because
> of the inherent dangers of using and charging unpackaged Li-Ion cells,
> Li-Ion batteries are always packaged together in a pack that has
> protection circuitry. By default you end up with a package that's easier
> to swap. On the other hand, NiMH batteries are usually not packaged
> together because there's an advantage of charging the cells
> individually, and because no protection circuitry is needed. You could
> design a system that discharged the pack in series but charged each cell
> individually (this has been used on things like bicycle lights) but it
> adds complexity and forces a proprietary pack.
>
>
>> Lower reliablity of devices that use them is flat wrong. If a device
>> is not
>> capable of determining the batteries are delivering too low of power to
>> prevent damage to the device, then NiMH and LiIon are equally
>> unreliable in
>> that device. If you use NiMH batteries in series in modern
>> electronics, the
>> risk is only to the battery and not to the device; and that risk being a
>> complete discharge and polarity reversal; which is almost impossible
>> with a
>> two battery series or less.
>
> It isn't the issue of too low of power, it's more a mechanical issue,
> one that most of us have experienced on battery powered devices. Look at
> the most commonly replaced part on AA powered digital cameras--it's the
> spring contact battery cover. It has constant pressure against it, and
> it's flimsy plastic. It's even worse if the the part that breaks is tabs
> in the camera body rather than tabs on the replaceable battery door. On
> cameras that use Li-Ion packs, the battery cover is usually not holding
> the battery contacts against the contacts inside the camera.
>
> Steve
> http://batterydata.com
I don't think you can blame the batter manufacturers for this. It is a
matter of convenience (and cost) taken by the camera manufacturer. It
is also probable that the AA batteries are removed more often that
Li-Ion batteries, so this makes the problem worse. Still not a fault of
the batteries.