Anyone have this system?

I really don't use a LOT of batteries but the idea of
throwing them away bothers me as we have no way to
recycle them here locally

I'm wondering if they would work ok in graphing
calculator?

Sorry to post here but didn't know where else to put
it.
Also, is there any diff between a cheap $13 Kodak NiMH
charger and more expensive $40 one?

Anyone have this system?

I really don't use a LOT of batteries but the idea of
throwing them away bothers me as we have no way to
recycle them here locally

I've been using Eneloops, and similar "ultra-low discharge" NiMH
batteries from other vendors, in both digital cameras and in the
AA-cell pack for a portable amateur radio.

They work quite well - they hold their charge quite well for many
months (much better than older-generation NiMHs).

I'm wondering if they would work ok in graphing
calculator?

Very probably - this is a relatively low-current-drain application and
you should get many hours of use out of a single charge.

Also, is there any diff between a cheap $13 Kodak NiMH
charger and more expensive $40 one?

The least-expensive chargers are probably simple fixed-current
slow-chargers, operating at around a ten-hour charge rate... they take
somewhere between 12 and 16 hours to load up fully-discharged cells.
Such chargers do work, but they stand a fairly good change of
overcharging the batteries if you don't know just how far discharged
they were when you started. Over time, too much overcharging can
reduce the cells' capacities and shorten their lifetime (although this
isn't a really serious problem at such low charge rates).

More expensive chargers will often run at a higher charging current
(faster charging) and have a sophisticated temperature-and-voltage
sensing circuit to detect the cells' full-charge state and turn off
the charge current. This is both better for the batteries (less
overcharging) and more convenient (a good charger can restore
fully-discharged batteries to full charge in a couple of hours).

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

If you don't use a lot of batteries, there's nothing wrong with using
disposables. You may never recoup the cost of the rechargeable batteries and
the recharger.

In my opinion, you should not use rechargeable cells in a calculator (unless
you always carry a backup pair), simply because they might drop dead when
you need them most. Nicad and NiMH cells are particularly bad in this
regard, because they have a flat discharge curve, followed by an abrupt
voltage dive, the worst-possible characteristics for any kind of battery,
especially rechargeables.

Rechargeables make the most sense for medium- to heavy-drain applications,
such as flashlights, motorized toys, and electronic flashes. Calculators are
light-drain, and probably not worth the trouble.

wrote:

Anyone have this system?

I really don't use a LOT of batteries but the idea of
throwing them away bothers me as we have no way to
recycle them here locally

I'm wondering if they would work ok in graphing
calculator?

I use Sanyo Eneloop AA batteries (as well as other brands of low
self-discharge NiMH batteries) in several devices, including a
police scanner, AA cell flashlight, cordless mouse, remote controls,
etc. I'll never go back to regular NiMH batteries, or alkaline for that
matter. I always have four or so fully charged ready to go.

BTW, I've used a Maha MH-C401FS charger for over two years. About $35.
I don't recommend cheap chargers for the reasons given by another poster.

UCLAN wrote:

BTW, I've used a Maha MH-C401FS charger for over two years. About $35.
I don't recommend cheap chargers for the reasons given by another poster.

OK thanks

I was really unsure of the cheap vs expensive charger!

I have Eneloops, Ray-O-Vac "Hybrid", and Duracell Low-Self-Discharge
batteries, and love them all. My children (and the rest of my family,
including me...) go through a lot of batteries, so I sprang for the best
charger (Just an opinion, there are other very good ones out there) - the
Ansmann Energy 16 (Paid $119 at Amazon.com) If you're just interested in
charging just AA's and AAA's, I think the LaCrosse BC-900 is a much better
choice (tells you actual maH accumulated charge!) for much less ($40 at
Amazon, free shipping) and comes with 4 each (total 8) AA and AAA batteries,
plus other accessories. It has features even my Ansmann does not, like
user-selectable charge rates, and a test mode with actual battery capacity
readout on a digital display. I haven't used one, but the reviews seem to
indicate that people are very happy with it.

If you don't want to spend the extra money on a good charger, I would
recommend you have extra batteries on hand, so you can switch them out when
one set is dead in your device(s), and charge only completely dead batteries
for only the time recommended by your charger for your capacity batteries.
As long as you're diligent in taking them off charge when they are done, and
are not trying to charge only "partially dead" batteries, you should be o.k.
Regardless of how they are charged, LSD batteries beat the pants off
"conventional" Nimh and Nicads - I use 'em in nearly everything. Circuit
City has been closing these out (eneloop) real cheap, like $6.00 for 4 AAs
or AAAs - I cleaned my store out - I can't imagine why they don't intend to
stock these any more. I don't think they marketed them properly in the
stores to explain to people what their advantages are.

wrote in message
...
Anyone have this system?

I really don't use a LOT of batteries but the idea of
throwing them away bothers me as we have no way to
recycle them here locally

I'm wondering if they would work ok in graphing
calculator?

Sorry to post here but didn't know where else to put
it.
Also, is there any diff between a cheap $13 Kodak NiMH
charger and more expensive $40 one?

"Haywire1" wrote in message
...
I have Eneloops, Ray-O-Vac "Hybrid", and Duracell Low-Self-Discharge
batteries, and love them all. My children (and the rest of my family,
including me...) go through a lot of batteries, so I sprang for the best
charger (Just an opinion, there are other very good ones out there) - the
Ansmann Energy 16 (Paid $119 at Amazon.com) If you're just interested in
charging just AA's and AAA's, I think the LaCrosse BC-900 is a much
better
choice (tells you actual maH accumulated charge!) for much less ($40 at
Amazon, free shipping) and comes with 4 each (total 8) AA and AAA
batteries,
plus other accessories. It has features even my Ansmann does not, like
user-selectable charge rates, and a test mode with actual battery capacity
readout on a digital display. I haven't used one, but the reviews seem to
indicate that people are very happy with it.

I would recommend the MAHA (Powerex) MH-C9000, which I _have_ used and am
very enthusiastic about.

I don't understand this business about "low self-discharge" NiMH batteries,
as I'ven never noticed any particular problem with them.

William Sommerwerck wrote:
I don't understand this business about "low self-discharge" NiMH batteries,
as I'ven never noticed any particular problem with them.

In order to have a lower self discharge rate, they have to have a higher
internal resistance. This lowers the effective charging rate, and the
output current.

I'm using Recyko+ battries sold by GPT out of Hong Kong. They are the
same batteries as one of them (there are only three companies that make
them), but I don't know which.

In order to get them to work, I have to charge them an awfully long time
with the chargers that have a fixed rate. For example the one that came
with the AAA batteries should charge them in 12 hours, I leave them on
at least 24 to get a useful charge. I also have one that times the
charge for 7 hours and I have to charge them twice.

With a normal NimH battery of the same capacity, the charger would charge
it completely in 7 hours.

Geoff.




--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

"Haywire1" wrote:

If you don't want to spend the extra money on a good charger, I would
recommend you have extra batteries on hand, so you can switch them out when
one set is dead in your device(s), and charge only completely dead batteries
for only the time recommended by your charger for your capacity batteries.
As long as you're diligent in taking them off charge when they are done, and
are not trying to charge only "partially dead" batteries, you should be o.k.

OK

Well I just don't want to spend a ton of
money cause I only have a "few" devices
that use AA or AAA right now and am
afraid the payback would be too long if
spending much money for charger and the
cells

In article ,
William Sommerwerck wrote:

I would recommend the MAHA (Powerex) MH-C9000, which I _have_ used and am
very enthusiastic about.

Agreed. The degree of control and information it provides is
wonderful.

I don't understand this business about "low self-discharge" NiMH batteries,
as I'ven never noticed any particular problem with them.

My own experiences are otherwise. "Traditional" NiMH batteries I
have used, would tend to lose a substantial fraction of their charge
within a few weeks, and would be nearly "flat" after three months of
storage.

The problem seems to be worse with the higher-capacity cells... a 2600
or 2700 mAh classic-NiMH cell would lose charge at a faster rate
(both absolute and percent-per-day) than an 1800 or 2000 mAh cell of
the same brand.

This isn't an absolute rule, though. I had a set of Lenmar "NoMEM
Pro" 2000 mAh cells which lost almost a third of their charge after
sitting around for only a week!

In certain applications - e.g. in the camera or flash unit of a very
busy photographer - the high-capacity "classic" NiMH cells may be the
best choice. It doesn't matter very much if they lose 2% of their
charge per day, if you're going to be running 'em down within a week
anyhow.

For low-rate or standby applications, the new ultra-low-discharge
cells are wonderful. I keep two sets of six in my ham-radio "go-kit"
for my spare dual-band handheld radio... each set will run the radio
through two 8-hour shifts of typical operation, and giving the a brief
topping-up charge every six months seems to be all that's required.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

William Sommerwerck wrote:

I don't understand this business about "low self-discharge" NiMH batteries,
as I'ven never noticed any particular problem with them.

There *is* no problem with them. I use several brands, including Sanyo
Eneloop. Low self-discharge NiMH batteries have made regular NiMH batteries
obsolete, IMO. [Except for in heavily used high current applications, only
because the capacity of low-discharge NiMH batteries is not yet as high as
regular NiMH batteries.]

Geoffrey S. Mendelson wrote:

I don't understand this business about "low self-discharge" NiMH batteries,
as I'ven never noticed any particular problem with them.

In order to have a lower self discharge rate, they have to have a higher
internal resistance. This lowers the effective charging rate, and the
output current.

I'm using Recyko+ battries sold by GPT out of Hong Kong. They are the
same batteries as one of them (there are only three companies that make
them), but I don't know which.

In order to get them to work, I have to charge them an awfully long time
with the chargers that have a fixed rate. For example the one that came
with the AAA batteries should charge them in 12 hours, I leave them on
at least 24 to get a useful charge. I also have one that times the
charge for 7 hours and I have to charge them twice.

With a normal NimH battery of the same capacity, the charger would charge
it completely in 7 hours.

That is a fault with your charger more than a fault of the batteries. I can
charge LSD NiMH batteries in a few hours in my Maha charger.

Dave Platt wrote:

My own experiences are otherwise. "Traditional" NiMH batteries I
have used, would tend to lose a substantial fraction of their charge
within a few weeks, and would be nearly "flat" after three months of
storage.

That's about right, if not pretty good. The discharge rate that Motorola
once claimed in an ancient phone manual I once had was 30% per week.

The problem seems to be worse with the higher-capacity cells... a 2600
or 2700 mAh classic-NiMH cell would lose charge at a faster rate
(both absolute and percent-per-day) than an 1800 or 2000 mAh cell of
the same brand.

In effect what they have done is traded off how long a charge lasts
versus hom huch that charge is. Unless you have the guts of a battery
hidden in a black hole, there is only so much room in the case.



In certain applications - e.g. in the camera or flash unit of a very
busy photographer - the high-capacity "classic" NiMH cells may be the
best choice. It doesn't matter very much if they lose 2% of their
charge per day, if you're going to be running 'em down within a week
anyhow.

For low-rate or standby applications, the new ultra-low-discharge
cells are wonderful. I keep two sets of six in my ham-radio "go-kit"
for my spare dual-band handheld radio... each set will run the radio
through two 8-hour shifts of typical operation, and giving the a brief
topping-up charge every six months seems to be all that's required.

That depends upon what power level you run the radio. I found that out in
the mid 1990's with the Ray-O-Vac rechargable alkelines. Everything I had
as except flashlights only worked for one or two charges before they
could not put out enough current to be of any use.

There were just some places that 1 watt would not open the local repeaters
even with an better quality rubber duck than the one that came with the
HT. Switching to higher power drew too much current. :-(

Geoff.



--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

UCLAN wrote:

That is a fault with your charger more than a fault of the batteries. I can
charge LSD NiMH batteries in a few hours in my Maha charger.

Sure, I can charge then in a few hours with a better charger too. But the
cheaper fixed current ones won't. The one that takes 24 hours is the
one that came with them. :-(

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

William Sommerwerck wrote:
"Haywire1" wrote in message
...
I have Eneloops, Ray-O-Vac "Hybrid", and Duracell Low-Self-Discharge
batteries, and love them all. My children (and the rest of my family,
including me...) go through a lot of batteries, so I sprang for the best
charger (Just an opinion, there are other very good ones out there) - the
Ansmann Energy 16 (Paid $119 at Amazon.com) If you're just interested in
charging just AA's and AAA's, I think the LaCrosse BC-900 is a much
better
choice (tells you actual maH accumulated charge!) for much less ($40 at
Amazon, free shipping) and comes with 4 each (total 8) AA and AAA
batteries,
plus other accessories. It has features even my Ansmann does not, like
user-selectable charge rates, and a test mode with actual battery capacity
readout on a digital display. I haven't used one, but the reviews seem to
indicate that people are very happy with it.

I would recommend the MAHA (Powerex) MH-C9000, which I _have_ used and am
very enthusiastic about.

I don't understand this business about "low self-discharge" NiMH batteries,
as I'ven never noticed any particular problem with them.



You've been lucky. I deal with a lot of 2-way radio handhelds that sit
idle for months at a time. The early NiMH batteries would self-drain to
unuseability in less that a month. At wurk, we replaced them all (at
least the ones we could find) after a year with newer technology NiMH
batteries like the Eneloops and such.

That is a fault with your charger more than a fault of the batteries. I can
charge LSD NiMH batteries in a few hours in my Maha charger.

Sure, I can charge then in a few hours with a better charger too. But the
cheaper fixed current ones won't. The one that takes 24 hours is the
one that came with them. :-(

There could be a number of things going in here.

You mention the higher resistance of the low-self-discharge cells.
Frankly I'm sceptical that this, by itself, could be great enough or
have enough effect on the battery to reduce the charging efficiency by
as much as you have observed. The low-self-discharge cells seem to be
able to discharge at rates of C/2 or even C/1 without their terminal
voltage dropping by very much, which means that the internal losses
aren't very high.

It's possible that the cheap charger you got with the batteries,
simply isn't very good - it may not be delivering as much current into
the batteries as it was supposed to. Possibly its internal current
regulator is poorly designed... if it consists only of a series
resistor hooked to a poorly-regulated DC voltage, then modest
variations in the DC supply voltage (from its internal transformer) or
in the battery's terminal voltage during charging could make a big
difference in the amount of current that the charger actually delivers
to the battery. You might be charging at a C/20 rate rather than a
C/10 rate. If the charger design was originally created for
lower-capacity cells, and wasn't revised when the capacities were
increased, it wouldn't be surprising if it's slow.

Another factor is something that I understand is true about NiMH cells
in general (not just the low-self-discharge type): charge acceptance
is quite poor at low charge rates. There seems to be a significant
"overhead cost" to charging... a fairly high fraction of the first
50-100 mA or so that you push into an AA cell just turns into heat,
rather than recharging the electrochemistry. Your charger may be
using such a low current rate that it's not actually making much
headway against this issue.

My impression is that a lot of the cheap/inexpensive "overnight"
chargers were originally designed for NiCd cells, and have been
re-branded as dual-chemistry (NiCd/NiMH) chargers without significant
change. Since NiMH cells typically have around twice as much capacity
as NiCd cells of the same size, it's not surprising that the charging
takes a long time.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

In article ,
Geoffrey S. Mendelson wrote:

In effect what they have done is traded off how long a charge lasts
versus hom huch that charge is. Unless you have the guts of a battery
hidden in a black hole, there is only so much room in the case.

Yup. I understand that it's an issue of the specific metal alloy and
structure that they use to create the hydride. Alloy structures which
bind the hydrogen more firmly have a lower self-discharge rate, but
less capacity per volume, and vice versa.

Changes in the plate separators also seem to be part of what they've
done to reduce the self-discharga rate.

Putting the guts in a black hole seems impractical... you just can't
get enough of the stored energy back out in Hawking radiation when you
really need it :-)

That depends upon what power level you run the radio. I found that out in
the mid 1990's with the Ray-O-Vac rechargable alkelines. Everything I had
as except flashlights only worked for one or two charges before they
could not put out enough current to be of any use.

In general, alkalines seem to be a poor choice for high-discharge
applications. Digicam owners have discovered this independently...
most digital cameras will "kill" alkalines quite quickly. I believe
I've read that the rechargeable alkalines were even worse in this
regard... their ESR rose significantly after a few charge/discharge
cycles. So, I don't find your experience at all surprising.

There were just some places that 1 watt would not open the local repeaters
even with an better quality rubber duck than the one that came with the
HT. Switching to higher power drew too much current. :-(

I've found the low-discharge NiMH cells to work quite well in my HT
even at high power.

Somebody over in one of the rec.radio.amateur newsgroups (I think it
was Roy but it might have been Cecil) posted an interesting point
about high-current usage recently. He noted that NiMH cells have a
reputation as being worse than NiCd, when high discharge currents are
required... presumably due to higher internal resistance.

His point was true that the comparison works out this way *only* if
you're doing the comparison on the basis of discharge rates in terms
of the battery's total capacity... say, how much energy is lost from
the battery at a C/2 or C/5 discharge rate. Measured in this way,
NiMH cells do come up looking rather worse than NiCd.

In many situations, though, this isn't the right question to ask. The
better question to ask is how much of the battery's total energy is
wasted, at a specific discharge rate measured in amperes (e.g. running
a given radio at high power, or taking photos with a digital camera).

When compared on this basis, modern NiMH cells come out looking about
the same as NiCd in terms of loss.

The reason for the difference, of course, is that the NiMH cells have
a much higher capacity (2x or so) than the corresponding NiCd cells.
They'd look worse in the first sort of comparison, even if their
internal resistance was identical with that of a NiCd, because they
were being tested at a higher absolute current level.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

That is a fault with your charger more than a fault of the batteries.
I can charge LSD NiMH batteries in a few hours in my Maha charger.

Like, wow, man. Trippy.

Another factor is something that I understand is true about
NiMH cells in general (not just the low-self-discharge type):
charge acceptance is quite poor at low charge rates.

I've heard this as well. Specifically, at "low" charge rates (which which
would actually be on the "high" side for nicads), NiMH cells are less likely
to enter the negative delta-V region that indicates end of charge.

Having grown up with nicads, I'm reluctant to charge faster than 0.1C, but
it appears that 0.3C and even 0.5C is acceptable with good-quality NiMH
cells.

That depends upon what power level you run the radio. I found that
out in the mid 1990's with the Ray-O-Vac rechargable alkelines.
Everything I had, except flashlights, only worked for one or two charges
before they could not put out enough current to be of any use.

In general, alkalines seem to be a poor choice for high-discharge
applications. Digicam owners have discovered this independently...
most digital cameras will "kill" alkalines quite quickly. I believe
I've read that the rechargeable alkalines were even worse in this
regard... their ESR rose significantly after a few charge/discharge
cycles. So, I don't find your experience at all surprising.

Alkalines were traditionally well-suited for high-drain applications. But
the Ray-O-Vac rechargeables had significantly higher internal resistance and
didn't handle high drain very well.

"UCLAN" wrote in message
...
William Sommerwerck wrote:

I don't understand this business about "low self-discharge" NiMH
batteries,
as I'ven never noticed any particular problem with them.

There *is* no problem with them. I use several brands, including Sanyo
Eneloop. Low self-discharge NiMH batteries have made regular NiMH
batteries
obsolete, IMO. [Except for in heavily used high current applications, only
because the capacity of low-discharge NiMH batteries is not yet as high as
regular NiMH batteries.

No, I meant regular NiMH cells.

I have a big pile of them, and recharge them as needed.

I don't understand this business about "low self-discharge" NiMH
batteries,
as I'ven never noticed any particular problem with them.

You've been lucky. I deal with a lot of 2-way radio handhelds that sit
idle for months at a time. The early NiMH batteries would self-drain to
unuseability in less that a month. At work, we replaced them all (at
least the ones we could find) after a year with newer technology NiMH
batteries like the Eneloops and such.

But why would you expect _any_ rechargeable battery (regardless of
chemistry) to keep its charge for several months?

Another factor is something that I understand is true about
NiMH cells in general (not just the low-self-discharge type):
charge acceptance is quite poor at low charge rates.

I've heard this as well. Specifically, at "low" charge rates (which which
would actually be on the "high" side for nicads), NiMH cells are less likely
to enter the negative delta-V region that indicates end of charge.

I think there are two effects here - how much of the energy going into
the battery is being lost as heat, and how much of an effect the heat
change has on the voltage. NiMH cells differ from NiCd in both
respects.

Having grown up with nicads, I'm reluctant to charge faster than 0.1C, but
it appears that 0.3C and even 0.5C is acceptable with good-quality NiMH
cells.

That does seem to be the case. It appears that there are a couple of
ways to charge NiMH cells fairly safely:

[1] At a nice, slow rate - .1C or even a bit lower. At this low rate,
the cells don't heat up very much at all, and thus don't exhibit the
zero-delta-V or negative-delta-V full-charge signature. For that
reason, neither a voltage- or temperature-sensing approach can be
used reliably, and a timed charge shutoff is the only alternative.

[3] Use a relatively fast charge rate - no less than .3C, with .5C or
even 1C being common. The cells do warm up significantly during
the fast-charging, and then their temperature starts to rise
sharply (and the voltage reaches zero-delta-V and starts down into
negative-delta-V) at full charge. Today's fast chargers seem to
use either T or delta-T as the primary shutoff indicator, with
delta-V as a secondary, and a timed shutoff as the final failsafe.

Early versions of the Maha/Powerex MH-9000 had a reputation for
occasional shutoff failure - they would not detect full charge
reliably, and the batteries would become quite hot as they cooked
away. Powerex revised the charger - I think they tweaked the firmware
logic having to do with the shutoff detection - and I understand that
they *raised* the minimum recommended fast-charge rate from 0.3C to
0.5C. Presumably this results in a more rapid temperature rise at
full-charge, and makes it easier to detect.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Early versions of the Maha/Powerex MH-9000 had a reputation for
occasional shutoff failure - they would not detect full charge
reliably, and the batteries would become quite hot as they cooked
away. Powerex revised the charger - I think they tweaked the firmware
logic having to do with the shutoff detection - and I understand that
they *raised* the minimum recommended fast-charge rate from 0.3C to
0.5C. Presumably this results in a more rapid temperature rise at
full-charge, and makes it easier to detect.

MAHA told me they've never revised the firmware (which I doubt). I've had no
termination-failure problems, even at 0.1C.

In article ,
William Sommerwerck wrote:

You've been lucky. I deal with a lot of 2-way radio handhelds that sit
idle for months at a time. The early NiMH batteries would self-drain to
unuseability in less that a month. At work, we replaced them all (at
least the ones we could find) after a year with newer technology NiMH
batteries like the Eneloops and such.

But why would you expect _any_ rechargeable battery (regardless of
chemistry) to keep its charge for several months?

Ummm... because [1] that's what I need that particular set of
batteries to do, in order to do my job, and [2] because that's what
the manufacturers are able to make them do, and advertise them to do?

Certainly, rechargeables are not likely to have the charge storage
lifetime of primary cells. However, NiCd batteries did/do have a
storage lifetime which makes it reasonable to use them for many
standby applications, and they have been used that way.
First-generation NiMH batteries were markedly worse than NiCd and
weren't suitable... but today's ultra-low-self-discharge NiMH actually
do the job quite nicely.

They also seem much less prone than alkalines to leak, if left in the
device while it's in storage. My experience is that new (unused)
alkalines seem to be quite stable in storage, but once you've used
more than a small fraction of their charge you've "started the clock
ticking" and they'll self-destruct after a couple of years of storage.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

William Sommerwerck wrote:
I don't understand this business about "low self-discharge" NiMH
batteries,
as I'ven never noticed any particular problem with them.

You've been lucky. I deal with a lot of 2-way radio handhelds that sit
idle for months at a time. The early NiMH batteries would self-drain to
unuseability in less that a month. At work, we replaced them all (at
least the ones we could find) after a year with newer technology NiMH
batteries like the Eneloops and such.

But why would you expect _any_ rechargeable battery (regardless of
chemistry) to keep its charge for several months?



It's not ME that's expecting that, it's the end users. You can baffle
them with technical answers until pigs fly, but they keep doing what WE
know doesn't work and complaining anyway.

Management is constantly bringing up having devices with rechargeable
batteries in emergency kits, but the only options are to let the idiots
break open a kit for a drill and finding a dead battery from
self-discharge or cooked to death from being in a charger. I've gone
thru this too many times to count on all upper and lower digits, even
including that digit in my pants.

The new-tech NiMH batteries will hold up for over three months and still
at least do a few radio checks. We put a huge placard in the kit to
CHARGE the damned radio overnight after drills, but they just toss them
back in the kits and bitch.

Back when you could get mercury-celled primary batteries, we'd put those
in the kits, but same idiots would pull them out of the kits for day-to
day use "just because we ran out of radios" and run them down and bitch
when they wouldn't charge. Same for alkaline primary battery packs....

You can't win.......

"Dave Platt" wrote in message
...

But why would you expect _any_ rechargeable battery (regardless
of chemistry) to keep its charge for several months?

, and [2] because that's what the manufacturers are able to make
them do, and advertise them to do?

I was talking in general terms. Until the Eneloop, I've never heard _any_
manufacturer claim their rechargeable cells would hold a charge for a "long"
perioud of time.

William Sommerwerck wrote:

There *is* no problem with them. I use several brands, including Sanyo
Eneloop. Low self-discharge NiMH batteries have made regular NiMH batteries
obsolete, IMO. [Except for in heavily used high current applications, only
because the capacity of low-discharge NiMH batteries is not yet as high as
regular NiMH batteries.

No, I meant regular NiMH cells.

I have a big pile of them, and recharge them as needed.

Yeah, I have a pile of them too. I just never use regular NiMH since the
low discharge ones got so cheap. I can put a pair of low discharge NiMH
AA cells in my 2-cell AA flashlight (which might go weeks without use),
and it's ready to use when needed. Last had to recharge those batteries
months ago. Try *that* with regular NiMH cells. Kodak even sells the
low discharge cells in a 4-pack, fully charged and ready to use. Find
*that* with regular NiMH cells? Heck no. My regular NiMH cells are now
only used in high-current, heavy use applications - where self discharge
isn't an issue. I have six remote control units and a cordless mouse that
use low-discharge NiMH batteries. They operate almost as long as alkalines.
Try *that* with regular NiMH cells.