Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #41   Report Post  
CMF
 
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Default AA battary capacity, Ah (?)

Quit interesting that you said that. Based on some of these posts, I am
going to check the next set of alkalines out of my HP 215. If it has the
same problem, then I bet the NiMH's won't be any better. God I hope not, I
sure would like a rechargeable solution.

Maury.

PS, All these conversations have my invention mind going; If I hit the big
time and get rich, I may throw you all a bone or something. :-)


"jakdedert" wrote in message
...
My old Olympus D-320L digicam goes through alkalines like crazy...but when
they won't work in the camera anymore, they still have plenty of capacity
for flashlights and the like.

I'll have to measure the open circuit voltage the next time I change them,
IIRC it was something like 1.3 volts.

jak

"Dave Martindale" wrote in message
...
(GregS) writes:

On the other hand, there is a GE discount CB walkie-talkie that has

been
sold
in many discount outlets. It uses a fixed amount of cells. It will ONLY
work with alkalines.
It NEEDS the extra voltage for the thing to output any decent power, 5
watts, where
the 1.2 volt cells will cause it to output 1/10th proper power level or

500mw.

Which means that it will use half or less of the energy in one set of
alkaline cells before you have to replace them with new ones.

This certainly fits my definition of "junk".

Dave






  #42   Report Post  
Venger
 
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"Eastburn" wrote in message
...
Remember - NiCad are 1.25 volts per cell. To low for some electronics
to function when in a higher voltage circuit.


Bingo... voltage = Alkalines, current = NiMH or Cd.

Also - Fry's had 2300mAh AA's when I was there yesterday. $13 for four of
them. YIKES!

Venger


  #43   Report Post  
Hard Ball
 
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On Tue, 15 Jul 2003 17:33:28 -0500, "jakdedert"
wrote:

My old Olympus D-320L digicam goes through alkalines like crazy...but when
they won't work in the camera anymore, they still have plenty of capacity
for flashlights and the like.

I'll have to measure the open circuit voltage the next time I change them,
IIRC it was something like 1.3 volts.

jak

"Dave Martindale" wrote in message
...


That's because capacity is dependent on current drain. In the camera
under high drain conditions they were done but when you put them in a
low drain device they found new capacity.

  #44   Report Post  
Dave Martindale
 
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"CMF" writes:
Quit interesting that you said that. Based on some of these posts, I am
going to check the next set of alkalines out of my HP 215. If it has the
same problem, then I bet the NiMH's won't be any better. God I hope not, I
sure would like a rechargeable solution.


You need to measure the voltage under load. That's particularly
important with high-current devices like a digital camera, or a 5 W
radio transmitter. There are some devices where the internal resistance
of the alkalines is the problem, not the design of the device.

For example, suppose you have a digicam that uses 2 AA cells, and it's
been properly designed to operate down to a voltage of 2 V. A pair of
alkalines start out a 3 V, but the camera sometimes draws enough current
(particularly with the LCD backlight on, and when recharging the flash)
that the voltage *under load* drops to 1.3 V. So far so good.

Now, after you've taken a few photos, the alkalines have dropped to a
no-load voltage of 1.3 V - meaning they still have most of their
capacity remaining. But the internal resistance increases as you
discharge the cells. Now, when you take a picture, the high current
momentarily causes the battery voltage to drop from 1.3 V to below 1 V,
and the camera shuts down.

NiCd and NiMH cells have *much* lower internal resistance than alkaline
cells, and it stays much lower throughout the discharge life of the
cells. These cells can deliver several amps of current with very little
voltage drop. So, although a pair of cells produce only 2.4 V, you
still get something like 2.3 V or 2.2 V under heavy load until the
battery is almost completely dead - and the camera continues working.

Basically, if alkaline cells power a device for a longer time than
current NiMH cells, then either the device has very low current drain
(where alkaline still does have more capacity), or the device hasn't
been designed to operate all the way down to 1 V per cell (bad design).
While if NiMH cells operate the device longer than alkaline cells, it's
probably because the device draws lots of current and the alkaline cells
have too much internal resistance.

Dave
  #45   Report Post  
CMF
 
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Actually, after borrowing a decent electronic multi-tester (would love to
buy one but if I had that kind of money I wouldn't be selling ironing
boards) I will rig to the power connections inside the camera and wire it to
a makeshift battery pack and test that. I can see how to do it now. I will
probably use some 24 gauge wire from a cat5 cable unless you think that will
not be enough.

As for measuring the way I did already, there are four batteries, two each
that drop down two slots and connect to the power leads inside the camera.
The lid closes the circuit, so I am testing the four batteries and the
camera circuitry I guess, with the lid open. I don't know how valid that
test is, but I am having fun.

Instead of all this testing, I could just get the charger and some
batteries, I just don't want to find out it won't work because this camera,
apparently an older model of the HP215, needs the alkaline voltage rush, so
to speak.

"Dave Martindale" wrote in message
...
"CMF" writes:

Okay, let me ask, how do I test under load? Does this mean see what

happens
to the voltage while in the camera, or when snapping a picture?


Ideally, yes. If you can't do that because you can't reach the camera's
battery terminals with the battery installed, maybe you can use clip
leads to connect the batteries (in a battery holder) to the camera
terminals. And if you can't do that either, perhaps you can measure the
current drawn by the camera, and then use a resistor that draws about
the same amount of current. What's practical depends on the mechanical
layout of your camera.

I was
piddling around with it this morning using an analog Sperry SP-152a
multitester, and it was showing 5 volts when I just took the battery cap

off
and touched the leads, where if I took all four batterys out and laid end

to
end, it showed 6. Remember, I am virtually ignorant of this stuff, and ha

ve
a cheap tester. The same tester shows almost 2 volts per battery, so I am
limited by a silly tester.


What in the camera is taking almost an entire volt even with the camera
turned off?


If you "take the battery cap off", what does the complete circuit with
the multimeter look like? Are you connecting the meter from the same
point where the camera takes its power? Or are you really removing an
inter-battery connection from the "far" end of the batteries and
measuring the voltage between the two exposed battery ends, but with the
camera electronics still in the loop?

If you're just measuring between two batteries in the middle of the
battery string, but the camera is also still in the circuit, the voltage
you measure just depends on the relative resistance of your meter and
the camera electronics in the "off" state, which is pretty meaningless.
If the camera had a mechanical "off" switch, you'd actually measure zero
volts in this case.

Dave





  #46   Report Post  
Rex B
 
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|Instead of all this testing, I could just get the charger and some
|batteries, I just don't want to find out it won't work because this camera,
|apparently an older model of the HP215, needs the alkaline voltage rush, so
|to speak.

As soon as I find my other two NiMh AAs, I'll pop them in my HP215 camera. I
have no doubt they will work fine. Will report.

  #48   Report Post  
Old Nick
 
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On Mon, 14 Jul 2003 15:27:05 -0700, "Sofie" wrote
something
.......and in reply I say!:

What about Dick Smith electronics????


wh....Oh, the half cells. I will give them a go. But they are not the
"electronics" shop they once were.
------------------------



"Old Nick" wrote in message
...
On Sat, 12 Jul 2003 17:34:37 -0700, "Sofie" wrote
something
......and in reply I say!:


************************************************** ****************************************
Huh! Old age!. You may hate it, but let me tell you, you can't get by for long without it!

Nick White --- HEAD:Hertz Music
Please remove ns from my header address to reply via email
!!
")
_/ )
( )
_//- \__/
  #49   Report Post  
CMF
 
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Rex,

Thanks. I just checked old messages, and you said you didn't read the
warning that my manual has. If you have the manual, can you look at page 42
in the users guide. Mine says: Caution: Do not use rechargeable batteries
with your HP Photosmart 215 digital camera.

If yours says this and they still work okay, then I will order some lickety
split. If your manual doesn't have this, then I wonder if they eliminated
this issue and you have an improved camera?



"Rex B" wrote in message
...
|Instead of all this testing, I could just get the charger and some
|batteries, I just don't want to find out it won't work because this

camera,
|apparently an older model of the HP215, needs the alkaline voltage rush,

so
|to speak.

As soon as I find my other two NiMh AAs, I'll pop them in my HP215 camera.

I
have no doubt they will work fine. Will report.



  #50   Report Post  
Rex B
 
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Maury

Actually, I have been using them in a HP315 (later model) for a year.
Just got a HP215 from someone here, and I intend to use rechargeables.
But your reminder suggests that I might get out BOTH manuals and see if they
both have that warnning.

Rex

On Wed, 16 Jul 2003 22:21:31 GMT, "CMF"
wrote:

|Rex,
|
|Thanks. I just checked old messages, and you said you didn't read the
|warning that my manual has. If you have the manual, can you look at page 42
|in the users guide. Mine says: Caution: Do not use rechargeable batteries
|with your HP Photosmart 215 digital camera.
|
|If yours says this and they still work okay, then I will order some lickety
|split. If your manual doesn't have this, then I wonder if they eliminated
|this issue and you have an improved camera?
|
|
|
|"Rex B" wrote in message
...
| |Instead of all this testing, I could just get the charger and some
| |batteries, I just don't want to find out it won't work because this
|camera,
| |apparently an older model of the HP215, needs the alkaline voltage rush,
|so
| |to speak.
|
| As soon as I find my other two NiMh AAs, I'll pop them in my HP215 camera.
|I
| have no doubt they will work fine. Will report.
|
|
|



  #51   Report Post  
James Waldby
 
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Gary Coffman wrote:
... Ted Edwards ... wrote:
Your friend was correct in recommending NiMH rechargeables,
you can get a decent set of 4 and a charger for about
$10 if you look for sales. Never need to pay more than
about $15.


Please don't do that! Those cheap chargers are either constant current
or timer terminated. Pay somewhat more and you can charge your
batteries whenever you feel like it without worrying about state of
charge. Ray-o-vac has a good charger but, personally, I like the Maha
line. My 204 isn't as versatile as some of the newer ones but it works
well. I paid Cdn$30 for it a couple years ago.
For example, see http://www.thomas-distributing.com/batteries.htm


Absolutely right! Get the MaHa charger. It will make your batteries
live longer because it won't abuse the batteries.


Disagree. I purchased an MH-C204F (and 4 MaHa batteries) 2.5 years
ago from Thomas and stopped using it 2 years ago after it ruined
2 sets of batteries. It apparently didn't turn off the fast charge
rate when the batteries were charged. The batteries overheated and
their plastic covers blistered and I got a very slight burn taking
them out of the charger.

My other charger (3 years old, obscure-brand POWERhaus Rapid Charger
PC-81) still works ok. I bought the 204 so I could charge 2 sets of 4
at once. After the first overheating incident on 25 July 2001, with my
Maha set of batteries, voltages on that set were reasonable (about 1.36V
each, straight off the charger) and the batteries appeared to work ok
for a while, but over the next few weeks or months their capacity
appeared to drop, and they now read 0 volts and won't take a charge.
The next day (26 July 2001) I put a different set of batteries
on the charger and checked every 15 minutes whether the red light had
gone off and green light come on, which happened after 2.5 hours, and
I decided the first incident had been a fluke. But eventually the
204 ruined another set of batteries and I stopped using it.

I agree with the advice to get a good charger with automatic
shutoff, but disagree that the Maha 204 is "absolutely right".
-jiw
  #52   Report Post  
Ted Edwards
 
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James Waldby wrote:

I agree with the advice to get a good charger with automatic
shutoff, but disagree that the Maha 204 is "absolutely right".


Either your batteries or your charger was defective. My 204 has been in
use now for almost two years with no problems whatsoever. Yours is the
first report I've seen with this problem. Did you contact the dealer
about the problem?

Ted

  #53   Report Post  
lcoe
 
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In rec.crafts.metalworking Ted Edwards wrote:
James Waldby wrote:

I agree with the advice to get a good charger with automatic
shutoff, but disagree that the Maha 204 is "absolutely right".


Either your batteries or your charger was defective. My 204 has been in
use now for almost two years with no problems whatsoever. Yours is the
first report I've seen with this problem. Did you contact the dealer
about the problem? Ted


if you google, he isn't the only one with the auto cycle failing and i now
believe that is why this RShack model has a "backup timer". the first set
i charged did not shut off at the 1hr mark, keep going until i monitered
that the voltage was remaining constant for about 5mins and i unplugged,
they were warm, not hot. this was after 90min.

but there would have been a 50% overcharge on that first go around, and
w/o the timer, who knows? they must not be able to designed a really
cheap auto charge sensor just yet. i have decided, based on my experience
and that of James, to return the RShack unit and just use the trickle
charger that came with the EverReady package at Sam's (19.99 for 8-1850mah
w/charger).

thanks again to EVERYONE who has posted to this thread, it really makes
Usenet SHINE! Best Regards, --Loren


  #54   Report Post  
CMF
 
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Loren,

What kind of batteries is with the eveready? I assume NiMH?

Thanks.
"lcoe" wrote in message
news:UqERa.75567$OZ2.13367@rwcrnsc54...
In rec.crafts.metalworking Ted Edwards wrote:
James Waldby wrote:

I agree with the advice to get a good charger with automatic
shutoff, but disagree that the Maha 204 is "absolutely right".


Either your batteries or your charger was defective. My 204 has been in
use now for almost two years with no problems whatsoever. Yours is the
first report I've seen with this problem. Did you contact the dealer
about the problem? Ted


if you google, he isn't the only one with the auto cycle failing and i now
believe that is why this RShack model has a "backup timer". the first set
i charged did not shut off at the 1hr mark, keep going until i monitered
that the voltage was remaining constant for about 5mins and i unplugged,
they were warm, not hot. this was after 90min.

but there would have been a 50% overcharge on that first go around, and
w/o the timer, who knows? they must not be able to designed a really
cheap auto charge sensor just yet. i have decided, based on my experience
and that of James, to return the RShack unit and just use the trickle
charger that came with the EverReady package at Sam's (19.99 for 8-1850mah
w/charger).

thanks again to EVERYONE who has posted to this thread, it really makes
Usenet SHINE! Best Regards, --Loren




  #55   Report Post  
JazzMan
 
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lcoe wrote:

In dfw.forsale CMF wrote:
Loren,


What kind of batteries is with the eveready? I assume NiMH?


yes, eight, 1850mah and 1x4charger that does ni-cad also. this
one does not do AAA like most of the auto models.

thanks to Jazzman for the Sam's plug. --Loren


You're gonna kill me for this, but I just looked at
my Eveready NiMH batteries that came with that
charger and they're only 1,700 mAh. I just
misread it when I bought them last year. Oddly
enough, they seem to outlast alkalines in my
digital camera by about 50% or more. Nevertheless,
they are 150mAh less than what I remembered them
to me.

JazzMan

--
***************************************
Please reply to jsavage"at"airmail.net.
Curse those darned bulk e-mailers!
***************************************


  #56   Report Post  
lcoe
 
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In sci.electronics.repair JazzMan wrote:
lcoe wrote:

In dfw.forsale CMF wrote:
Loren,


What kind of batteries is with the eveready? I assume NiMH?


yes, eight, 1850mah and 1x4charger that does ni-cad also. this
one does not do AAA like most of the auto models.

thanks to Jazzman for the Sam's plug. --Loren


You're gonna kill me for this, but I just looked at
my Eveready NiMH batteries that came with that
charger and they're only 1,700 mAh. I just
misread it when I bought them last year. Oddly


no worries, i read that off the batteries, NH15-AA 1.2v-1850mah.
i cannot find the package so dunno what it says, they must just
be keeping the product current.

it is amazing, right now, you can pay plenty for the little buggers
if you do not keep up with the market. --Loren

enough, they seem to outlast alkalines in my
digital camera by about 50% or more. Nevertheless,
they are 150mAh less than what I remembered them
to me.


JazzMan


--
***************************************
Please reply to jsavage"at"airmail.net.
Curse those darned bulk e-mailers!
***************************************

  #57   Report Post  
Rex B
 
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On Thu, 17 Jul 2003 23:59:49 GMT, lcoe wrote:

|In sci.electronics.repair JazzMan wrote:
| lcoe wrote:
|
| In dfw.forsale CMF wrote:
| Loren,
|
| What kind of batteries is with the eveready? I assume NiMH?
|
| yes, eight, 1850mah and 1x4charger that does ni-cad also. this
| one does not do AAA like most of the auto models.
|
| thanks to Jazzman for the Sam's plug. --Loren
|
|
| You're gonna kill me for this, but I just looked at
| my Eveready NiMH batteries that came with that
| charger and they're only 1,700 mAh. I just
| misread it when I bought them last year. Oddly
|
|no worries, i read that off the batteries, NH15-AA 1.2v-1850mah.
|i cannot find the package so dunno what it says, they must just
|be keeping the product current.
|
|it is amazing, right now, you can pay plenty for the little buggers
|if you do not keep up with the market. --Loren

OK, so where's the best place to buy NiMh batteries?
I checked at the local Big Lots and all they have is a few NiCads.


  #58   Report Post  
Doug McLaren
 
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In article , Rex B wrote:

| OK, so where's the best place to buy NiMh batteries?
| I checked at the local Big Lots and all they have is a few NiCads.

Don't put down NiCd's so quickly -- they have lower resistance than
NiMh so your flash may recharge faster, and they can be charged faster
(2C is usually safe), and they tolerate abuse better, so they last
longer.

I don't know what Big Lots has (probably not much), but Home Depot
sells 4 pack 800 mA AA NiCd packs for $5. (Near/for the solar powered
lawn lights.) You can find up to 1100 mA AA NiCds (not at Home Depot)
but you'll pay a lot more.

NiCd have their niche, but most people want NiMH. For AA NiMH cells,
buy them at www.mcmelectronics.com. Search for 58-7740. If you buy
at least ten, the price is $0.84 each. Looks like shipping is $3+the
actual postal charge. So if you need a lot of batteries, that's a
great deal. (Beware, most of their other prices suck.)

(I've bought about 50 of these batteries. They work great.)

| Newsgroups: sci.electronics.repair,dfw.forsale,rec.crafts.meta lworking

Sorry if people consider this offtopic in these groups. But maybe
this post will help shut down this long-lasting thread

--
Doug McLaren,
Virtue has its own reward, but no box office. --Mae West
  #61   Report Post  
Rex B
 
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On Fri, 18 Jul 2003 14:49:00 GMT, (Doug McLaren) wrote:

|In article , Rex B wrote:
|
|| OK, so where's the best place to buy NiMh batteries?
|| I checked at the local Big Lots and all they have is a few NiCads.

|NiCd have their niche, but most people want NiMH. For AA NiMH cells,
|buy them at
www.mcmelectronics.com. Search for 58-7740. If you buy
|at least ten, the price is $0.84 each. Looks like shipping is $3+the
|actual postal charge. So if you need a lot of batteries, that's a
|great deal. (Beware, most of their other prices suck.)

|This place has cheap prices if you are in the US and want to buy $50+
|worth (I've not tried them):

|http://www.cheapbatteries.com/nimh.htm

Thanks folks, both good sources.

Any place local?
  #62   Report Post  
Ted Edwards
 
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Rex B wrote:

OK, so where's the best place to buy NiMh batteries?


One very reputable dealer is
http://www.thomas-distributing.com/batteries.htm
They have a lot of info on their site as well.

Ted


  #63   Report Post  
Robert Akins
 
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I'm sure Tanner Electronics has some, but I don't know what brand or
capacity they are. Also, see what Batteries Plus has.
Robert
"Rex B" wrote in message
...
On Fri, 18 Jul 2003 14:49:00 GMT, (Doug McLaren) wrote:

|In article , Rex B wrote:
|
|| OK, so where's the best place to buy NiMh batteries?
|| I checked at the local Big Lots and all they have is a few NiCads.

|NiCd have their niche, but most people want NiMH. For AA NiMH cells,
|buy them at
www.mcmelectronics.com. Search for 58-7740. If you buy
|at least ten, the price is $0.84 each. Looks like shipping is $3+the
|actual postal charge. So if you need a lot of batteries, that's a
|great deal. (Beware, most of their other prices suck.)

|This place has cheap prices if you are in the US and want to buy $50+
|worth (I've not tried them):

|http://www.cheapbatteries.com/nimh.htm

Thanks folks, both good sources.

Any place local?



  #64   Report Post  
CMF
 
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Oh, I never thought about Batteries Plus. I'm sure they won't be the
cheapest, but the on on Central just north of 15th street (west side) has
some good people working there. I have been for some other things.

I was just at Target, and looked at their Eveready chargers for grins. It
said the NiMH were 1.2 volt. based on my feeble testing, if my HP215 needs
voltage and not amperage for the pictures, they won't work, because I still
have 1.3 or so using my analog multitester (I got better with it since
whining yesterday) on these, and around 5.5 when I put 4 together after the
camera says batteries too low to take a picture. I can still look at
pictures stored on the camera for a while even when I cannot take the
pictures, so I need to find out whether it is voltage or amperage that I
need for pictures. I believe it has already been covered in this thread, I
will go back and look unless someone has a quick answer.


"Robert Akins" wrote in message
...
I'm sure Tanner Electronics has some, but I don't know what brand or
capacity they are. Also, see what Batteries Plus has.
Robert
"Rex B" wrote in message
...
On Fri, 18 Jul 2003 14:49:00 GMT, (Doug McLaren)

wrote:

|In article , Rex B

wrote:
|
|| OK, so where's the best place to buy NiMh batteries?
|| I checked at the local Big Lots and all they have is a few NiCads.

|NiCd have their niche, but most people want NiMH. For AA NiMH cells,
|buy them at
www.mcmelectronics.com. Search for 58-7740. If you buy
|at least ten, the price is $0.84 each. Looks like shipping is $3+the
|actual postal charge. So if you need a lot of batteries, that's a
|great deal. (Beware, most of their other prices suck.)

|This place has cheap prices if you are in the US and want to buy $50+
|worth (I've not tried them):

|http://www.cheapbatteries.com/nimh.htm

Thanks folks, both good sources.

Any place local?





  #65   Report Post  
Ted Edwards
 
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lcoe wrote:

Don't put down NiCd's so quickly -- they have lower resistance than
NiMh so your flash may recharge faster, and they can be charged faster


This was true. It still is to a very small extent but there have been
major advances in NiMH technology even just in the last couple of years.

NiCd have their niche, but most people want NiMH.


Given what you say, why would they? I am serious, as I am puzzled. I
thought NiMH were far better, but I am beginning to wonder why.


1100mAh is about tops for AA NiCd's whereas NiMH AA's are now up to
about twice that. Twice as many pictures on your digital camera or
twice as many hours on your GPSR is a significant advantage. If you are
into caring for the environment, when they do die and go to the
landfill, NiMH does not contain any highly toxic Cadmium.

for most all applications, my guess is that they are. but have been
too expensive for low-end consumer products. they do self discharge
much faster than NiCads, bad for cell/cordless phones, both, they
take 1/10C overcharge indefinitely w/o damage, good for phones (read
this on a website).


This is all old/incorrect data. The self discharge rate is a *little*
higher than NiCd but not much any more. Prices have come way down.
Zellers (in Canada) is selling 1850mAh AA cells for Cdn$16 for a four
pack. Get a smart charger and don't worry about running them right down
before re-charging.
http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM
http://www.thomas-distributing.com/batteries.htm
http://www.buchmann.ca/

"new technology". oh, also, iirc new Nicad's have an indefinite
shelf life(?).


Are you refering to self discharge or just sitting out of use? If the
latter, I have seen no evidence of any superiority of NiCd over NiMH in
sealed cells.


lastly, i just bot a mid-priced Panasonice cordless 2.4gDSS which
uses Nicad's.


I don't know what a 2.4gDSS is but if it takes AA cells, try a set of
NiMH. You may be pleasantly surprised.

Ted




  #66   Report Post  
Dave D
 
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Default AA battary capacity, Ah (?)


"Ted Edwards" wrote in message
...

lastly, i just bot a mid-priced Panasonice cordless 2.4gDSS which
uses Nicad's.


I don't know what a 2.4gDSS is but if it takes AA cells, try a set of
NiMH. You may be pleasantly surprised.

Ted



In cases where an appliance is designed to use and charge NiCads, replacing
the cells with NiMH is not necessarily a good idea. For starters, to get
the extra capacity out of the cells they will either have to be charged at a
proportionally higher current, or for a proportionally longer time. If the
base unit has an 'intelligent' NiCad charger it may not charge the cells
correctly at all.

Dave


  #67   Report Post  
lcoe
 
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Default AA battary capacity, Ah (?)

In rec.crafts.metalworking Ted Edwards wrote:
lcoe wrote:

Don't put down NiCd's so quickly -- they have lower resistance than
NiMh so your flash may recharge faster, and they can be charged faster


This was true. It still is to a very small extent but there have been
major advances in NiMH technology even just in the last couple of years.


for most all applications, my guess is that they are. but have been
too expensive for low-end consumer products. they do self discharge
much faster than NiCads, bad for cell/cordless phones, both, they
take 1/10C overcharge indefinitely w/o damage, good for phones (read
this on a website).


This is all old/incorrect data. The self discharge rate is a *little*
higher than NiCd but not much any more. Prices have come way down.


all? what all? the overcharge immunity? the fact that some manufacturer
will design in NiCads even if the cost is similar, to provide product
distinction?

"new technology". oh, also, iirc new Nicad's have an indefinite
shelf life(?).


Are you refering to self discharge or just sitting out of use? If the
latter, I have seen no evidence of any superiority of NiCd over NiMH in
sealed cells.


shelf life. this was "common knowledge" some years ago, but never have
read anything very authoritive about it. are you saying a NiMH battery,
unused, will be as good a a NiCad after 5yrs on the shelf? what exactly
_are_ you saying? that you haven't run a test personally so do not believe
it? --Loren


  #68   Report Post  
Spehro Pefhany
 
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On Sun, 20 Jul 2003 17:10:25 -0500, the renowned "jakdedert"
wrote:

The issue of NiMH's in the cradle too long is easily surmounted...and will
get cheaper to do as the demand increases...as always with electronics and
production volume.


In my (not cheap) Siemens phone system, only a few years old, designed
for NiCds, the NiMH batteries last MUCH longer than good quality
(Panasonic) NiCds. I don't recommend it, of course, but it WORKS, and
it's a lot cheaper than either buying a new phone system or buying
dozens of NiCds.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
  #69   Report Post  
CMF
 
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Default AA battary capacity, Ah (?)

Okay, back to a topic that has been covered already, and I can always look
it up, but why look up when you can ask?

I have done some testing with my HP215, and the batteries seem to still have
1.2-1.3 volts when they can no longer take a picture, but I can then put
them in my headlight flashlight (makes me look like a nerd, but works
wonders in attics) and they are just marvelous. I don't know just how long
they will go, but they still test right at the good and then '?' on my
Sperry analog multimeter. What does the Multimeter check when it does a
battery check? Voltage or amperage? The manual is hopelessly inadequate, and
about all I am real strong with is the buzz feature.

Does this pretty much indicate that 1.2 V NiMH's will not really suit me in
this camera? I can't really spend the money for a decent charger and
batteries if it really isn't going to work, because that d&%m camera is our
main battery pig. Many of the battery powered toys are magically
disappearing. I don't suppose someone in Wylie/East Plano would loan me a
set of NiMH's for a few days?

Thanks,

Maury


  #70   Report Post  
James Waldby
 
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Default AA battary capacity, Ah (?)

Ted Edwards wrote:

James Waldby wrote:

I agree with the advice to get a good charger with automatic
shutoff, but disagree that the Maha 204 is "absolutely right".


Either your batteries or your charger was defective. My 204 has been in
use now for almost two years with no problems whatsoever. Yours is the
first report I've seen with this problem. Did you contact the dealer
about the problem?


I agree that either the batteries or charger were defective.
Since the batteries were in use and working well until the
charger cooked them, I think the problem is in the Maha 204.
No, I didn't contact Thomas Distrib. re the problem.

-jiw


  #72   Report Post  
Ted Edwards
 
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Default AA battary capacity, Ah (?)

lcoe wrote:

charge NiMH, maybe a sample defecit. bu, my testing comports with a
web page that states, "NiMH" does _not_ exhibit the 'reverse' voltage
rise property of NiCAD's when reaching full charge.


They do but not as strongly. NiMH smart chargers will do NiCd but the
converse is usually false.

Ted

  #73   Report Post  
jakdedert
 
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"lcoe" wrote in message
et...
In sci.electronics.repair Spehro Pefhany wrote:
On Sun, 20 Jul 2003 17:10:25 -0500, the renowned "jakdedert"
wrote:

The issue of NiMH's in the cradle too long is easily surmounted...and

will
get cheaper to do as the demand increases...as always with electronics

and
production volume.


In my (not cheap) Siemens phone system, only a few years old, designed
for NiCds, the NiMH batteries last MUCH longer than good quality
(Panasonic) NiCds. I don't recommend it, of course, but it WORKS, and
it's a lot cheaper than either buying a new phone system or buying
dozens of NiCds.


what does, "easily surmounted" mean, wrt this discussion? --Loren

...meaning that it's fairly easy to design a circuit to stop charging once
the battery is fully charged--the advantage cited for NiCads was that they
better tolerated overcharging.

Look for a smart NiMH charger on a single chip at your electronics supplier
soon (today, maybe?)--just add transformer. Once production ramps up, and
the circuit--or ones like it--gets second-sourced, the price will go down
precipitously...like your $40 VCR which would have cost you $1500 in 1977.

jak

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the

reward"
Info for manufacturers:

http://www.trexon.com
Embedded software/hardware/analog Info for designers:

http://www.speff.com



  #75   Report Post  
Old Nick
 
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Default AA battary capacity, Ah (?)

On Sun, 20 Jul 2003 19:39:27 GMT, Ted Edwards wrote
something
.......and in reply I say!:

Thanks Ted and others. Capacity ruuuuules OK! G

Given what you say, why would they? I am serious, as I am puzzled. I
thought NiMH were far better, but I am beginning to wonder why.


1100mAh is about tops for AA NiCd's whereas NiMH AA's are now up to
about twice that. Twice as many pictures on your digital camera or
twice as many hours on your GPSR is a significant advantage. If you are
into caring for the environment, when they do die and go to the
landfill, NiMH does not contain any highly toxic Cadmium.


************************************************** ****************************************
Huh! Old age!. You may hate it, but let me tell you, you can't get by for long without it!

Nick White --- HEAD:Hertz Music
Please remove ns from my header address to reply via email
!!
")
_/ )
( )
_//- \__/


  #76   Report Post  
lcoe
 
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Default AA battary capacity, Ah (?)

In rec.crafts.metalworking Ted Edwards wrote:
lcoe wrote:

charge NiMH, maybe a sample defecit. bu, my testing comports with a
web page that states, "NiMH" does _not_ exhibit the 'reverse' voltage
rise property of NiCAD's when reaching full charge.


They do but not as strongly. NiMH smart chargers will do NiCd but the
converse is usually false. Ted


that same site states ....termination methods used for NiMH, include temp
sensing...,..timer(?),...(other?)....

the RShack unit (returned now) had the switch for NiCadNiMH and two
values for the "backup" timer, 2hrs for the former, 1.5 hrs for the latter.
likely the product is simply a NiCad charger with timers but they do
provide two charging currents, 200ma(?)vs 800ma. (and they lie
thru their teeth about the additional modes). --Loren


  #77   Report Post  
Ted Edwards
 
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lcoe wrote:

that same site states ....termination methods used for NiMH, include temp
sensing...,..timer(?),...(other?)....


Just which site is this? Why is it anomynous? If you check the
manufacturers sites (Eveready, Ray-oVac, ...) The site I gave you
previously (on testing beatteries for cameras) and more, you will find
that your reference is simply wrong. Do a search with Google or Dogpile
and read some of the material.

the RShack unit (returned now) had the switch for NiCadNiMH and two
values for the "backup" timer, 2hrs for the former, 1.5 hrs for the latter.


I've never been overly impressed with Radio Shack's products so I don't
find that a very definitive source.

Ted

  #78   Report Post  
lcoe
 
Posts: n/a
Default AA battary capacity, Ah (?)

In rec.crafts.metalworking Ted Edwards wrote:
lcoe wrote:

that same site states ....termination methods used for NiMH, include temp
sensing...,..timer(?),...(other?)....


Just which site is this? Why is it anomynous? If you check the


well, i just spent an hour trying to find that url, struck out, it must
have been a link from a Usnet group. similarly i cannot find another
url i visited this am that talks about "Zero Delta V" detection which
i assume is for NiMH. it doesn't reverse, just stops rising.

and that comports with yet _another_ mystery site that said a NiMH can
take 1/10C overcharge indefinitely (or it may have been 1/18C), which
shortens the life of Nicads.

manufacturers sites (Eveready, Ray-oVac, ...) The site I gave you
previously (on testing beatteries for cameras) and more, you will find
that your reference is simply wrong. Do a search with Google or Dogpile
and read some of the material.


the Thomas Distributing site has quite a bit on the charger/battery technology
and states that three methods are recognized (by MAHA) to recharge batteries,
delta V, timer, and temp, that only delta V does not overcharge. then they
say, ....good designs will incorporate all three, like the MAHA....

anyhoo, just my own personal experience, take it for what it is. --Loren

  #79   Report Post  
Ted Edwards
 
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lcoe wrote:

and that comports with yet _another_ mystery site that said a NiMH can
take 1/10C overcharge indefinitely (or it may have been 1/18C), which
shortens the life of Nicads.


C/10 for continuous charging of NiMH is still controversial. Some say
C/20 and some would like to see continuous float as low as C/60. The
jury is still out on the long term stuff since the cells haven't been
around all that long and there has been considerable advance in the
technology over the last few years.

Ted

  #80   Report Post  
CMF
 
Posts: n/a
Default AA battary capacity, Ah (?)

Please kind sir, can you explain what you mean by C/10 and C/20, etc? In
terms my simpleton mind can understand? Thanks.

Maury
"Ted Edwards" wrote in message
...
lcoe wrote:

and that comports with yet _another_ mystery site that said a NiMH can
take 1/10C overcharge indefinitely (or it may have been 1/18C), which
shortens the life of Nicads.


C/10 for continuous charging of NiMH is still controversial. Some say
C/20 and some would like to see continuous float as low as C/60. The
jury is still out on the long term stuff since the cells haven't been
around all that long and there has been considerable advance in the
technology over the last few years.

Ted



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