need to buy rechargeable D cell batteries and a charger
JC Dill
charger? Fry's? Radio Shack? Any online battery sites I should check
first? The batteries will be used in a boom-box (it takes 6 batteries,
we want 2 sets).
Thanks!
jc
John R Pierce
will the boombox perform adequately on 6*1.2V = 7.2V instead of 6*1.5V =
9V ? I know my last relatively high power boombox could barely handle
running on Alkaline D cells, it was much happier on AC at higher volume
levels (it would distort above about 4-5 with the D cells while it could
be cranked up to 7-8 cleanly with AC power... this one ran on 10 D cells
for 15V)
as far as where, Radio Shack has a pretty good selection of NiCad and NiMH
batteries. make sure you always use them til they are nearly flat, then
fully charge them, and you'll get the maximum power and number of charge
cycles (200-400 full charge/discharge cycles are typical if they are well
kept, used frequently, and not used or charged when its too hot or too
cold). before the first use, charge them extra long to insure they are
fully charged.
finding a 6 D cell charger might be a challenge, my last NiMH sets were AA
and the charger did 4 at a time, which was perfect for my digital camera
at the time.
I wouldn't by a candy bar at Fry's, it would probably be pre-eaten, and
re-wrapped.
Oh, if you have one in your area, Batteries Plus carries a good range of
quality rechargables, albeit at a premium price.
Oh, and... Watch out for NiCad or NiMH "D" cells that seem rather
light... those in fact have a "C" sized cell inside a "D" sized plastic
tube. Finding full "D" Ni***'s is more challenging, but I think RatShack
has some.
John Navas
In <nPhTc.7497$54.1...@typhoon.sonic.net> on Sat, 14 Aug 2004 05:55:31 GMT,
JC Dill <usenet-s...@vo.cnchost.com> wrote:
>Where's the best place to get 12 rechargeable D cell batteries and a
>charger? Fry's? Radio Shack?
Costco. WalMart.
>Any online battery sites I should check
>first? ...
Thomas Distributing.
--
Best regards,
John Navas <http://navasgrp.home.att.net/>
CABLE MODEM/DSL GUIDE: <http://Cable-DSL.home.att.net/>
JC Dill
> [POSTED TO ba.internet - REPLY ON USENET PLEASE]
>
> In <nPhTc.7497$54.1...@typhoon.sonic.net> on Sat, 14 Aug 2004 05:55:31 GMT,
> JC Dill <usenet-s...@vo.cnchost.com> wrote:
>
>>Where's the best place to get 12 rechargeable D cell batteries and a
>>charger? Fry's? Radio Shack?
>
> Costco. WalMart.
I have never seen rechargeable D cells at Costco, just their standard 12
and 24 packs of use-once-and-throw-away batteries. Last night the
Mountain View WalMart had just a few 2-battery blister packs, and no
charger that could take more than 2 D-cells at a time.
>>Any online battery sites I should check
>>first? ...
>
> Thomas Distributing.
Yikes. Their prices are high!
jc
John Navas
In <3GpTc.7526$54.1...@typhoon.sonic.net> on Sat, 14 Aug 2004 14:51:43 GMT,
JC Dill <usenet-s...@vo.cnchost.com> wrote:
>John Navas wrote:
>
>> In <nPhTc.7497$54.1...@typhoon.sonic.net> on Sat, 14 Aug 2004 05:55:31 GMT,
>> JC Dill <usenet-s...@vo.cnchost.com> wrote:
>>
>>>Where's the best place to get 12 rechargeable D cell batteries and a
>>>charger? Fry's? Radio Shack?
>>
>> Costco. WalMart.
>
>I have never seen rechargeable D cells at Costco, just their standard 12
>and 24 packs of use-once-and-throw-away batteries.
Costco stores here in the Tri-Valley have carried Panasonic rechargeable kits
that included D cells, although I don't know if they currently have them.
>Last night the
>Mountain View WalMart had just a few 2-battery blister packs, and no
>charger that could take more than 2 D-cells at a time.
That's a drawback to WalMart -- actual stocking is hit-or-miss.
>>>Any online battery sites I should check
>>>first? ...
>>
>> Thomas Distributing.
>
>Yikes. Their prices are high!
I personally find their prices competitive, and their service tops.
I presume you know that there are two basic kinds of rechargeable D cells,
those effectively with a AA inside (i.e., AA capacity), and those with real D
cell capacity (4-5 x AA capacity). The latter are much more expensive than
the former, due to both increased materials and decreased scale/demand.
do...@needxtoxbu.usenet.us.com
> I presume you know that there are two basic kinds of rechargeable D cells,
> those effectively with a AA inside (i.e., AA capacity), and those with real D
> cell capacity (4-5 x AA capacity). The latter are much more expensive than
> the former, due to both increased materials and decreased scale/demand.
If you are in the South Bay, there is R&D Electronics, on Montague Expy
near Capitol. They have the "real" D Cells, and lots of other component
stuff. No PC's for sale ;-)
http://www.randdelectronicparts.com/
I have liked these guys since they were a fledging startup at the same time
I was a fledging startup.
--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
Dennis Holmes
Don't know what's best, but I've ordered from batteryspace.com before.
They have a decent selection of stuff and the prices seemed pretty
good.
--
+---------------------------------------------------------------------+
| Dennis Holmes 1st initial then last name at email.rahul.net |
| San Jose, CA Disclaimer: I'm temporarily insane. |
+----=>{ Meanwhile, as Ford said: "Where are my potato chips?" }<=----+
Jeff Liebermann
<spamf...@navasgroup.com> wrote:
>I presume you know that there are two basic kinds of rechargeable D cells,
>those effectively with a AA inside (i.e., AA capacity), and those with real D
>cell capacity (4-5 x AA capacity). The latter are much more expensive than
>the former, due to both increased materials and decreased scale/demand.
I used to build my own D cells out of AA cells. The problem was that
the real D cells (4AH) were radically more expensive than cheapo AA
cells (about 0.9AH). I also had a large pile of cheapo .675AH AA
NiCd cells. I would cut a 2" wide strip of cardboard packing wrap
(kinda like a flexible version of a cardboard shipping box), and build
the diameter of the AA cell up to slightly less than a D cell (1.25")
and secure it with duct tape. The AA cell had to be removeable
because my overly intelligent charger set the charge rate based on the
size of the cell and would therefore overcharge a AA cell. Many years
ago, I mass produced about 50 of these adapters, which are now found
mostly in my various flashlights and one boom box.
Incidentally, another reason for the removeable cells is that I was
experimenting with ultra-fast chargeing of NiCd batteries. I achieved
semi-reliable chargeing of a .675AH AA cell from about 25% to 95% in
about 30 seconds at 10-13 amps charge current. This is about 200
times the recommended chargeing current. If the cell is genuinely
discharged, then there is no heating or outgassing up to about 95% of
full charge. Unfortunately, anything over 95% tends to create a messy
and toxic explosion. It also only works on one cell at a time as the
slightly different voltage distribution for series connected cells
will result in some cells being partially charged, while others are
overcharged (or explode). The effect is minor at low charge currents
(C/10) but a major problem at ultra high charge currents (20C).
Obviously, this method is not ready for commercialization.
For the boom box, I've also used remote control electric toy car
battery packs. The 9.6V flavour should work as a 6 cell replacement.
Some wiring and butchery will be required.
http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=273
I also have some 8V gel cells but they're far too heavy for portable
operation.
--
Jeff Liebermann je...@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
Anthony Guzzi
> Costco stores here in the Tri-Valley have carried Panasonic rechargeable kits
> that included D cells, although I don't know if they currently have them.
I just recently invested 15 dollars into a Panasonic NiMH charger from
the Costco here in Chico, it's AA and AAA only, and it came with 6 AAs
at 2100 mAh and 2 AAAs at 750 mAh.
I was actually going to ask the group even before this thread, why would
freshly charged AAs measure only 1.3 volts, instead of the 1.6 or 1.7
volts of brand new Alkelines? Are the batteries or the charger
defective or low quality? I know my multimeter isn't. :-)
Also, I've heard (after I bought the setup) to beware of chargers that
only charge based on a timer, instead of measuring the voltage and
charging based on that. How can I tell which this is?
I kind of wished I'd waited and got a good charger that will do more
batteries at a time, and does D's also. Even though I don't use Ds that
often, my 4 cell Maglite eats them for breakfast. :-)
-Anthony-
poldy
John Navas <spamf...@navasgroup.com> wrote:
> Costco stores here in the Tri-Valley have carried Panasonic rechargeable kits
> that included D cells, although I don't know if they currently have them.
Do you want NiMH?
At my closest Costco, they have these Panasoic kits but with mostly AA
and a couple of AAA batteries.
Seems those are the most popular sizes or NiMH doesn't scale up to the
bigger capacities?
No Li ion rechargeables in the standard sizes yet.
poldy
Anthony Guzzi <duke...@sonic.net> wrote:
I got that kit as well. It's a good value, just for the 6 AA NiMh alone.
Frys has a big selection of various brands of NiMH batteries, including
lesser-known brands which seem to have longer charge times and lower
prices than the name-brand ones.
John Higdon
poldy <po...@kfu.com> wrote:
> No Li ion rechargeables in the standard sizes yet.
Those batteries can get pretty nasty if charged inproperly. I suspect
that the reason you don't see them in "popular sizes" is the possibility
of people mistakenly or ignorantly popping them into common NiCd or NiMH
chargers and starting a fire. A great deal of the magic of Li ion
batteries is in the rather smart charging circuitry associated with the
devices that use them.
--
John Higdon | Email Address Valid | SF: +1 415 428-COWS
+1 408 264 4115 | Anytown, USA | FAX: +1 408 264 4407
Marty
I think I thought I saw this post from Jeff Liebermann
<je...@comix.santa-cruz.ca.us>:
> . . .
>Incidentally, another reason for the removeable cells is that I was
>experimenting with ultra-fast chargeing of NiCd batteries. I achieved
>semi-reliable chargeing of a .675AH AA cell from about 25% to 95% in
>about 30 seconds at 10-13 amps charge current. This is about 200
>times the recommended chargeing current. If the cell is genuinely
>discharged, then there is no heating or outgassing up to about 95% of
>full charge. Unfortunately, anything over 95% tends to create a messy
>and toxic explosion.
Is this all part of your "Learn by Destroying" philosophy? :-)
I heard batteries last longer using a slow charge - do you know if this is
true (obviously, it last longer if you don't blow them up, too)? I'm
building up a collection of chargers (AA), as the first one was a
timer-only, slow charger, then I got a better, faster, non-timer. Then I
needed one that had a cigarette lighter adapter for camping (this is all
mostly for cameras or portable music players).
I got 4 AAs from Fry's last week for my camera, 2350 ma/h, to try out. I
forget the brand, but I never heard of them. I'll see how they do.
--
Marty - mjf at leftcoast-usa.com
"Those are my principles, and if you don't like them...
well, I have others." - Groucho Marx
John Navas
In <BKXTc.7782$54.1...@typhoon.sonic.net> on Mon, 16 Aug 2004 05:37:37 GMT,
Anthony Guzzi <duke...@sonic.net> wrote:
>John Navas wrote:
>
>> Costco stores here in the Tri-Valley have carried Panasonic rechargeable kits
>> that included D cells, although I don't know if they currently have them.
>
>I just recently invested 15 dollars into a Panasonic NiMH charger from
>the Costco here in Chico, it's AA and AAA only, and it came with 6 AAs
>at 2100 mAh and 2 AAAs at 750 mAh.
>
>I was actually going to ask the group even before this thread, why would
>freshly charged AAs measure only 1.3 volts, instead of the 1.6 or 1.7
>volts of brand new Alkelines?
Difference in battery chemistry -- NiCd and NiMH start off with lower voltage
than alkaline, but hold that voltage much better under load and as they are
depleted than alkaline.
>Are the batteries or the charger
>defective or low quality? I know my multimeter isn't. :-)
That's normal.
>Also, I've heard (after I bought the setup) to beware of chargers that
>only charge based on a timer, instead of measuring the voltage and
>charging based on that. How can I tell which this is?
See if it's a smart charger that senses end of charge. Generally speaking,
smart chargers are more expensive than dumb chargers, and most better fast (2
hr or less) chargers are smart chargers.
Jeff Liebermann
wrote:
>Somewhere around Sun, 15 Aug 2004 10:49:56 -0700, while reading ba.internet,
>I think I thought I saw this post from Jeff Liebermann
><je...@comix.santa-cruz.ca.us>:
>> . . .
>>Incidentally, another reason for the removeable cells is that I was
>>experimenting with ultra-fast chargeing of NiCd batteries. I achieved
>>semi-reliable chargeing of a .675AH AA cell from about 25% to 95% in
>>about 30 seconds at 10-13 amps charge current. This is about 200
>>times the recommended chargeing current. If the cell is genuinely
>>discharged, then there is no heating or outgassing up to about 95% of
>>full charge. Unfortunately, anything over 95% tends to create a messy
>>and toxic explosion.
>> . . .
>Is this all part of your "Learn by Destroying" philosophy? :-)
Yep. If you haven't blown something up, you don't understand how it
works. It goes well with making burnt offerings to the computer gods
by sacrificing an old 386 motherboard on the hibachi. Things tend to
work better after such cerimonies.
>I heard batteries last longer using a slow charge - do you know if this is
>true (obviously, it last longer if you don't blow them up, too)?
Actually, I don't know. The problem is that my source of AA NiCd's
and NiMH batteries delivers used batteries. My guess is they have
been cycled anywhere between 1 and 300 times. I do a bin sort by
remaining capacity (full charge and discharge into load while
monitoring on a data logger). The bad ones are fairly obvious.
I did use my ultra fast charge tester to cycle test a few brand new
cells. It's a bit difficult to accurately determine remaining
capacity but I was able to cycle these cells about 100 times and still
have about 50% of the initial capacity left. I should do this with a
conventional charge (C/10) as a comparison. Yet another project.
Anyway, there was no obvious detrimental effects or accellerate ageing
shown.
Begin heresy():
There's no such thing as NiCd memory effect. What I've seen and
measured instead is electrolyte loss. Overchargeing a battery causes
heating. Heating causes the over-pressure seal on the battery to
vent. It vents KOH electrolyte. When the electrolyte runs dry, the
battery goes dead. I've "rejuvinated" NiCd's by fileing a notch in
the edge of the cell (near the + terminal) and injecting some KOH with
a syringe. I then seal the hole with solder. This doesn't work with
cells that have formed dendrites, but seems to work for overheated
batteries.
End heresy():
>I'm
>building up a collection of chargers (AA), as the first one was a
>timer-only, slow charger, then I got a better, faster, non-timer. Then I
>needed one that had a cigarette lighter adapter for camping (this is all
>mostly for cameras or portable music players).
Drivel: I blew up a Canon A-70 camera by using AA alkaline cells.
The cell difference between 1.35VDC and 1.5VDC was enough to fry the
internal regulator.
>I got 4 AAs from Fry's last week for my camera, 2350 ma/h, to try out. I
>forget the brand, but I never heard of them. I'll see how they do.
Those are NiMH batteries. Don't try my ultra fast charge method on
NiMH. What happens is that NiMH has a higher internal resistance. On
chargeing, that means it will dissipate substantially more heat than a
NiCd. I have a mess on the workbench to demonstrate the effect.
Also, at very low charge levels (< C/20), both NiCd's and NiMH cells
will simply not charge at all. I'm not sure of the chemistry or how
that works. I've just seen it during my testing.
The way the non-timer chargers work is that they detect the slight
decrease in terminal voltage just before the battery is fully charged.
That's a known point on the charge curve and the circuit can easily
estimate how much more to shove into the battery to get a full charge
wihtout going over. There's quite a bit more info on the various chip
manufacturers web piles:
http://www.maxim-ic.com/appnotes.cfm/appnote_number/68
http://www.maxim-ic.com/appnotes10.cfm/ac_pk/5/ln/en
John Navas
In <b1p1i015mthpce572...@4ax.com> on Mon, 16 Aug 2004 16:47:39
GMT, Marty <this.a...@is.invalid> wrote:
>I heard batteries last longer using a slow charge - do you know if this is
>true (obviously, it last longer if you don't blow them up, too)? ...
It's true in general, but overly simplistic. Better chargers will do less
harm even at faster charging rates. What matters is the type of charging, and
avoidance of over-temperature and over-charging -- with proper charging,
modern cells can be recharged without harm in less than an hour. It's also
helpful to have a charger that charges cells individually, since when charging
more than one cell, cell mismatch can result in destructive over-charging of
the stronger cell.
>I got 4 AAs from Fry's last week for my camera, 2350 ma/h, to try out. I
>forget the brand, but I never heard of them. I'll see how they do.
Brand does matter -- some of the cheapie brands are significantly worse than
the better ones.
John Navas
In <poldy-DC897A....@netnews.comcast.net> on Mon, 16 Aug 2004
Most popular -- it does scale.
>No Li ion rechargeables in the standard sizes yet.
And there won't be in the future, since the cell voltage is twice as high.
A sort of standard size is the new Lithium-Ion RCR-V3, which works in devices
designed to take either two AA or a single CR-V3. That works because the cell
voltage of CR-V3/RCR-V3 (single-use/rechargeable) is roughly the same as two
AA (alkaline or rechargeable).
Philip J. Koenig
Guzzi) writes...
> John Navas wrote:
>
> > Costco stores here in the Tri-Valley have carried Panasonic rechargeable kits
> > that included D cells, although I don't know if they currently have them.
>
>
> I just recently invested 15 dollars into a Panasonic NiMH charger from
> the Costco here in Chico, it's AA and AAA only, and it came with 6 AAs
> at 2100 mAh and 2 AAAs at 750 mAh.
>
> I was actually going to ask the group even before this thread, why would
> freshly charged AAs measure only 1.3 volts, instead of the 1.6 or 1.7
> volts of brand new Alkelines? Are the batteries or the charger
> defective or low quality? I know my multimeter isn't. :-)
The standard voltage of Nickel-Cadmium cells is ~1.25v per cell.
It has to do with the chemistry of the device. For example, many
"9 volt" Ni-Cad batteries are actually typically 7.2v because
they're composed of 6 1.2v cells.
The other difference between Zinc-Manganese or Alkaline batteries
and Ni-Cads is that Ni-Cad voltage remains relatively stable over
its useful lifespan, whereas the former types gradually lose
voltage. This is why you cannot just assume NiCads will work in
every device, actually in some devices it may damage them. (their
typically higher momentary current output - due I believe to
lower internal resistance - is the main reason for this)
--
* Few people are capable of expressing with equanimity opinions which *
* differ from the prejudices of their social environment. Most people are *
* even incapable of forming such opinions. -- Albert Einstein *
* *
* To send email, remove numbers and spaces: pjkusenet64 @ ekahuna27 . com *
* Simple answers are for simple minds. Try a new way of looking at things. *
John R Pierce
<absolutel...@verislimesucks.com> wrote:
>> No Li ion rechargeables in the standard sizes yet.
>
>Those batteries can get pretty nasty if charged inproperly. I suspect
>that the reason you don't see them in "popular sizes" is the possibility
>of people mistakenly or ignorantly popping them into common NiCd or NiMH
>chargers and starting a fire. A great deal of the magic of Li ion
>batteries is in the rather smart charging circuitry associated with the
>devices that use them.
also, Li-Ion rechargables are 2V per cell, instead of the 1.5V of
alkalines, or 1.3V of NiCad/NiMH.
John Navas
In <em02i0tmu7vt34j98...@4ax.com> on Mon, 16 Aug 2004 12:19:00
-0700, Jeff Liebermann <je...@comix.santa-cruz.ca.us> wrote:
>Begin heresy():
>There's no such thing as NiCd memory effect. What I've seen and
>measured instead is electrolyte loss. Overchargeing a battery causes
>heating. Heating causes the over-pressure seal on the battery to
>vent. It vents KOH electrolyte. When the electrolyte runs dry, the
>battery goes dead. I've "rejuvinated" NiCd's by fileing a notch in
>the edge of the cell (near the + terminal) and injecting some KOH with
>a syringe. I then seal the hole with solder. This doesn't work with
>cells that have formed dendrites, but seems to work for overheated
>batteries.
>End heresy():
So-called "memory effect" actually refers to voltage depression. When NiCd
batteries are repeatedly discharged only partially, the discharge voltage can
be depressed (reduced) by about 150 mV per cell. Although there is some
debate about the severity of this problem, the source is generally considered
to be the formation of large crystals by the cadmium electrode. Since NiMH
batteries do not use cadmium, so-called "memory" is not an issue. If venting
from overheating were the cause, then one would expect NiMH to be similarly
affected, if not more so, due to more heat being generated during charging as
compared to NiCd, yet they're not.
>Drivel: I blew up a Canon A-70 camera by using AA alkaline cells.
>The cell difference between 1.35VDC and 1.5VDC was enough to fry the
>internal regulator.
Something else was going on, since the A70 is speced to take "AA Alkaline
battery x4". See <http://makeashorterlink.com/?Z12E56019> or
<http://consumer.usa.canon.com/ir/controller?act=ModelTechSpecsAct&fcategoryid=145&modelid=8776>
>Those are NiMH batteries. Don't try my ultra fast charge method on
>NiMH. What happens is that NiMH has a higher internal resistance. On
>chargeing, that means it will dissipate substantially more heat than a
>NiCd. I have a mess on the workbench to demonstrate the effect.
The bigger problem is that NiMH is exothermic on charge, whereas NiCd is
endothermic on charge. Nonetheless, NiMH is capable of very rapid charging
given proper control of the charging process, as evidenced by 30 min charging
of dumb AA NiMH batteries by Energizer, and 15 min charging of smart AA NiMH
batteries in the Rayovac I-C3 system.
>Also, at very low charge levels (< C/20), both NiCd's and NiMH cells
>will simply not charge at all. I'm not sure of the chemistry or how
>that works. I've just seen it during my testing.
C/10 is commonly used for slow charging.
C/40 is commonly used for to maintain cell capacity.
>The way the non-timer chargers work is that they detect the slight
>decrease in terminal voltage just before the battery is fully charged.
>That's a known point on the charge curve and the circuit can easily
>estimate how much more to shove into the battery to get a full charge
>wihtout going over. There's quite a bit more info on the various chip
>manufacturers web piles:
> http://www.maxim-ic.com/appnotes.cfm/appnote_number/68
> http://www.maxim-ic.com/appnotes10.cfm/ac_pk/5/ln/en
Sensing the rate of increase in voltage is better, looking for the beginning
of the knee in the voltage curve, since there is less overcharging than when
waiting for the later decrease in voltage. Temperature sensing is better yet.
Best is pressure sensing.
A good NiMH information source is <http://makeashorterlink.com/?M26E62019> or
<http://data.energizer.com/batteryinfo/application_manuals/nickel_metal_hydride.htm>
Here's what it has to say:
Determining when overcharge has occurred is critical to charging
schemes that minimize the amount of time spent at high charge rates
in overcharge. In turn, these efficient charging techniques are a key
to maximizing cell life, as will be discussed later. Primary charge
control schemes typically depend on sensing either the dramatic rise
in cell temperature illustrated in Figure 18 or the peak in voltage
show in Figure 19.
Charge control based on temperature sensing is the most reliable
approach to determining appropriate amounts of charge for the
nickel-metal hydride cell. Temperature-based techniques are thus
recommended over voltage-sensing control techniques for the primary
charge control mechanism.
The advanced Rayovac I-C3 charger (that I mentioned above) uses pressure
sensing in the battery cell itself.
John Navas
In <oh52i0h5ien772l1d...@news.lmi.net> on Mon, 16 Aug 2004
Lithium-Ion is actually about 3.6 volts per cell.
Jeff Liebermann
<spamf...@navasgroup.com> wrote:
>What matters is the type of charging, and
>avoidance of over-temperature and over-charging -- with proper charging,
>modern cells can be recharged without harm in less than an hour.
Maxim has a design for a 4C charger which translates into a 15 minute
charge. However, they taper the charge to prevent accidental
overchargeing resulting in a 30 minute charge. See:
http://pdfserv.maxim-ic.com/en/an/A0910.pdf
>It's also
>helpful to have a charger that charges cells individually, since when charging
>more than one cell, cell mismatch can result in destructive over-charging of
>the stronger cell.
Right on. I've killed more batteries by effectively reverse chargeing
one cell while connected in series in a battery pack. Unfortunately,
the cheap camera battery chargers tend to do two at a time (2.7VDC)
which I guess is better than chargeing 4, 6, or 8 cells at a time.
>Brand does matter -- some of the cheapie brands are significantly worse than
>the better ones.
Hint: How many battery manufactories are there in the world?
Answer: About 15 when I last checked around 1999. They make lots of
specials and private labels, but essentially there are a limited
number of sources and manufactories.
The basic differences are sintered electrode construction and pocket
plate cells. The sintered type are the considerably heavier weight,
but higher capacity NiCd's. The pocket plate are the light weight
cheapies. Unfortunately, the sintered plate type do not appreciate a
fast charge. (Sintered plate are also used in Aircraft starter
batteries). In the case of NiMH, they're all pocket plate
construction.
John Navas
In <lj92i0psu3h15flo1...@4ax.com> on Mon, 16 Aug 2004 14:46:01
-0700, Jeff Liebermann <je...@comix.santa-cruz.ca.us> wrote:
>On Mon, 16 Aug 2004 19:43:53 GMT, John Navas
><spamf...@navasgroup.com> wrote:
>
>>What matters is the type of charging, and
>>avoidance of over-temperature and over-charging -- with proper charging,
>>modern cells can be recharged without harm in less than an hour.
>
>Maxim has a design for a 4C charger which translates into a 15 minute
>charge. However, they taper the charge to prevent accidental
>overchargeing resulting in a 30 minute charge. See:
> http://pdfserv.maxim-ic.com/en/an/A0910.pdf
Rayovac has a true 4C charger -- full charge in only 15 minutes.
http://rayovac.com/products/recharge/recharge.shtml
>>Brand does matter -- some of the cheapie brands are significantly worse than
>>the better ones.
>
>Hint: How many battery manufactories are there in the world?
>Answer: About 15 when I last checked around 1999. They make lots of
>specials and private labels, but essentially there are a limited
>number of sources and manufactories.
True, but some are a lot worse than others, just as in the case of CD-R/RW and
DVD+-R/RW manufacturing.
>The basic differences are sintered electrode construction and pocket
>plate cells. ...
With all due respect, there are lots of other differences, including design,
chemistry, construction, packaging, and quality control.
John R Pierce
wrote:
>>also, Li-Ion rechargables are 2V per cell, instead of the 1.5V of
>>alkalines, or 1.3V of NiCad/NiMH.
>
>Lithium-Ion is actually about 3.6 volts per cell.
OUCH, I knew that. dunno where 2V came from, yeesh, except recently I've
been dealing with sealed lead acid stuff...