Products specifying alkaline batteries

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I have an electronic scale that uses a 9v battery and it says "use alkaline
batteries only".  I prefer to use rechargeable NiMH batteries. How can the
product tell the difference (or can it) and what would be the problem, if
any, of using non-alkaline batteries in such a product.

Thanks,
noozer


Re: Products specifying alkaline batteries
On Wed, 11 Oct 2006 14:47:28 +0000, BE Has Frothed:

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As they discharge, the voltage drops off more linear in an alkaline. The
rechargable stays more constant then drops off rapidly. Hence the scale
will operate longer on an alkaline.

--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

Re: Products specifying alkaline batteries
Meat Plow ( snipped-for-privacy@meatplow.local) writes:
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Maybe more important, rechargeables don't start with the same voltage
level as fresh alkalines, and if the unit counts on the voltage being
above a certain point, the useable "life" of the rechargeable will
not be so long (though of course, they can be recharged).

I used to have something, it might have been my Radio Shack Model
100 laptop, that I used rechargeables in, and they sure didn't last
as long as alkalines.  On the other hand, the rechargeables could
be recharged so I got more long term life out of them than the alkalines.

  Michael


Re: Products specifying alkaline batteries
snipped-for-privacy@FreeNet.Carleton.CA (Michael Black) writes:

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The bottom line is it almost certainly won't hurt the equipment so may be
worth trying.  For something like an electronic scale, rechargeables
may indeed be fine.

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Re: Products specifying alkaline batteries

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For an electronic scale,I'd use a wallwart.

--
Jim Yanik
jyanik
at
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Re: Products specifying alkaline batteries
On Wed, 11 Oct 2006 16:53:59 +0000, Michael Black Has Frothed:

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I'm a ham and what's important to me is that the current in rechargables
remains constant until the end of the charge. It's important in power
hungry portable ham radio gear to have that constant current until it's
time to recharge.

--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

Re: Products specifying alkaline batteries

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Does anyone MAKE a "9V" NiMH battery?

--
Jim Yanik
jyanik
at
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Re: Products specifying alkaline batteries



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I have one in front of me ( a cheapie ) that I recharged a month or two
back.

It currently measures 8.99V.

Graham


Re: Products specifying alkaline batteries
On 10/11/06 6:52 PM, in article Xns9859CA3ACC6B3jyanikkuanet@129.250.170.84,

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I just bought several Energizer Rechargeable "9v" batteries (NiMH) and,
thanks to a previous post, I looked at the fine print and, yes, it is
actually 7.2volts!  It says: "Size 9v" - so they can claim it is a 9v
battery due to the loose use of the term "9v" to indicate a "size" rather
than a power potential.

Why would the makers of these rechargeables make them not truly match the
voltage they are supposed to be?

noozer


Re: Products specifying alkaline batteries
BE (n3wsr3ad3r_|@|_sbcglobal.net) writes:
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Because it's a chemical matter.

A cell puts out about 1.5v. If you need more voltage, you combine them.
So when the need for 9v batteries came along, they had to combine six
cells in the package.  Or maybe they decided on package size, and then
picked a voltage that would fit the package.  Open up a 9v battery,
and you'll see six invidual cells.  In some, it's 6 sort of lumps, but
in others it's sort of like skinny AAA cells inside.  If they needed
more voltage, they'd have to add more cells, and the package would be
bigger for the same amount of current.

Nicads put out about 1.2v.  That too is a chemical issue.  The only
way they can get a higher voltage is by combining cells in the same
package, but that cuts current capacity (since the cells would
be smaller), and results in not the needed 1.5v but 2.4 volts.

So when they combine 6 nicad cells in a "9v battery" package,
6 * 1.2 =7.2volts.  Again, the only way to fix that is by putting
mroe cells inside that package, and while that's more feasible than
with a straight AA cell, it forces each to be a physically smaller
cell and that likely impacts on the current the whole thing
can supply.

In some cases, equipment has been designed with all this in mind.
The battery compartment will be big enough to accomodate more
batteries than the needed voltage would require in alkaline batteries.
So that old CB walkie talkie would have a place for 10 AA batteries,
so if they are nicads it gets 12v.  It would then come with a pair
of dummy AAs, that merely fill space and provide contact end to end,
so when using alkaline AAs you would simply put in 10 AAs and the
dummies, and still get 12volts.

  Michael

Re: Products specifying alkaline batteries



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Because they like fat profits ?

Buy the chaep ones instead. I did and it is actually 9V.

Graham


Re: Products specifying alkaline batteries
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If you're talking Ni-Cads or NiMH, it's unlikely to be a 8 cell PP3 if
cheap.

The initial open circuit voltage of a Ni-Cad is pretty irrelevant. After a
short time under load it will settle at 1.2v per cell and stay there for
most of the usable range. Alkalines are dying from the second they're
used. ;-)

--
*Why don't you ever see the headline "Psychic Wins Lottery"?

    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: Products specifying alkaline batteries

Dave Plowman (News) Wrote:
> In article snipped-for-privacy@hotmail.com, Eeyore

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> is

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> match

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> After a

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> for

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Coming back to the original posting, the manufacturer was probably
suggesting the use of  alkaline batteries is preferred - as against
carbon zinc types with their inherently poor shelf life and leaking
electrolyte.




--
pebe


Re: Products specifying alkaline batteries
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Because upping the number of cells within the same package may not result
in any real benefits. Indeed, apart from increasing the cost, it may end
up with a lower capacity. It depends on how sensitive the device is to
voltages at the lower end of what an alkaline cell produces.

--
*According to my calculations, the problem doesn't exist.

    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: Products specifying alkaline batteries

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Rechargable batteries tend to have a lower voltage than non-rechargable,
so the voltage difference might cause trouble.  My guess is the "Use
alkaline batteries only" is there because the manufacturer knows the
device likes to eat batteries for breakfast, lunch, and dinner.

Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

Re: Products specifying alkaline batteries

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Or pehaps the current drain is so low that alkalines will last for years,
and rechargables will self discharge in days to weeks.  For low drain
devices like clocks, calculators, and scales with LCD displays, or other
infrequently used devices, rechargables do not really make sense.  Alkalines
have a shelf life of several years.

CK



Re: Products specifying alkaline batteries

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Very good point!

--
Jim Yanik
jyanik
at
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Re: Products specifying alkaline batteries
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However, the terminal usable voltage of an alkaline will be very similar
to that of a Ni-Cad, etc.

--
*Succeed, in spite of management *

    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: Products specifying alkaline batteries



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I discovered recently that Duracell quote battery lifetime to 50% of initial
voltage ! Any rechargeable will be far better.

Graham


Re: Products specifying alkaline batteries
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Hi...

The voltage of a brand new alkaline is 1.5 volts.  The
voltage of a freshly charged nimh or nicd is 1.2 volts.

The likelihood is that your scale will see the 1.2 volts,
and decide that the battery is due for replacement - at worst
refuse to operate; at best tell you to change the battery.

Take care.

Ken



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