Battery choice: 9V vs 6 AAs

[Adam Funk]

I'm fixing a kid's toy that was damaged by corrosion (stored with the
batteries). The only damaged part was the battery compartment, so I
opened it up, clipped off the internal wires to that bit, soldered
extensions on them & ran those through holes in the case, in order to
put an external 6 AA holder on. As it turns out, the 6 AA battery
holder I bought clips onto a 9 V battery attachment, which I had in
stock. As I was putting this together, I realized that 6 AAs in
series make about 9 V, so I'm wondering why a toy would run on 6 AAs
when 1 9V would be smaller & easier?



(Yes, I know it should be "cells" rather than "batteries".)

Thanks.

--
Specifications are for the weak & timid!
--- Klingon Programmer's Guide

 

[Tom Biasi]

On 5/5/2015 7:41 AM, Adam Funk wrote:

I'm fixing a kid's toy that was damaged by corrosion (stored with the
batteries). The only damaged part was the battery compartment, so I
opened it up, clipped off the internal wires to that bit, soldered
extensions on them & ran those through holes in the case, in order to
put an external 6 AA holder on. As it turns out, the 6 AA battery
holder I bought clips onto a 9 V battery attachment, which I had in
stock. As I was putting this together, I realized that 6 AAs in
series make about 9 V, so I'm wondering why a toy would run on 6 AAs
when 1 9V would be smaller & easier?



(Yes, I know it should be "cells" rather than "batteries".)

Thanks.

Look up the amount of current the AAs can supply vs. the 9 volt.

 

[John Fields]

On Tue, 05 May 2015 12:41:25 +0100, Adam Funk <a24061@ducksburg.com>
wrote:

I'm fixing a kid's toy that was damaged by corrosion (stored with the
batteries). The only damaged part was the battery compartment, so I
opened it up, clipped off the internal wires to that bit, soldered
extensions on them & ran those through holes in the case, in order to
put an external 6 AA holder on. As it turns out, the 6 AA battery
holder I bought clips onto a 9 V battery attachment, which I had in
stock. As I was putting this together, I realized that 6 AAs in
series make about 9 V, so I'm wondering why a toy would run on 6 AAs
when 1 9V would be smaller & easier?



(Yes, I know it should be "cells" rather than "batteries".)

Thanks.

---
The capacity of the AAs is much greater than the capacity of the 9V.

John Fields

 

>"As well as being way cheaper per amp-hour. "

HAHA.

Got these elcheapo meters from Harbor Freight. At one time they were on sale for like $3.99. I looked at a nine volt battery in the store and it was $4.99.

Actually if you can grab their coupons, they actually give these meters away for free sometimes. Meter = free. Battery = ridiculous.

 

Adam Funk <a24061@ducksburg.com> wrote:

As I was putting this together, I realized that 6 AAs in series make
about 9 V, so I'm wondering why a toy would run on 6 AAs when 1 9V
would be smaller & easier?

As has been mentioned, 6 AA cells have a lot more capacity than one 9 V
battery. To put some numbers on it:

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/NA_DATASHEETS/MN1500_US_CT.pdf

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/NA_DATASHEETS/MN1604_6LF22_US_CT.pdf

Look at the first graph in both data sheets. At a constant 10 mA load,
the 9 V will last about 60 hours, while the stack of AAs will last about
320 hours; the AAs last 5.3x as long. In the second graph, at a
constant 100 mA, the 9 V is good for 3 hours, while the AAs are good for
about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and about
22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4 cm^3.

Looking at pricing, Wal-Mart sells a two-pack of Rayovac 9 V batteries
for $5.47, or $2.735 each. They sell a 4-pack of Rayovac AAs for $2.97
($0.743 each) or an 8-pack for $4.97 ($0.621 each). This makes a string
of 6 AAs cost something around $3.73 to $4.46; more expensive than the
9 V battery, but also better performance.

Matt Roberds

 

[Phil Hobbs]

On 5/5/2015 9:10 AM, John Fields wrote:

On Tue, 05 May 2015 12:41:25 +0100, Adam Funk <a24061@ducksburg.com
wrote:

I'm fixing a kid's toy that was damaged by corrosion (stored with the
batteries). The only damaged part was the battery compartment, so I
opened it up, clipped off the internal wires to that bit, soldered
extensions on them & ran those through holes in the case, in order to
put an external 6 AA holder on. As it turns out, the 6 AA battery
holder I bought clips onto a 9 V battery attachment, which I had in
stock. As I was putting this together, I realized that 6 AAs in
series make about 9 V, so I'm wondering why a toy would run on 6 AAs
when 1 9V would be smaller & easier?



(Yes, I know it should be "cells" rather than "batteries".)

Thanks.

---
The capacity of the AAs is much greater than the capacity of the 9V.

John Fields

As well as being way cheaper per amp-hour.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[Michael Black]

On Tue, 5 May 2015, Adam Funk wrote:

I'm fixing a kid's toy that was damaged by corrosion (stored with the
batteries). The only damaged part was the battery compartment, so I
opened it up, clipped off the internal wires to that bit, soldered
extensions on them & ran those through holes in the case, in order to
put an external 6 AA holder on. As it turns out, the 6 AA battery
holder I bought clips onto a 9 V battery attachment, which I had in
stock. As I was putting this together, I realized that 6 AAs in
series make about 9 V, so I'm wondering why a toy would run on 6 AAs
when 1 9V would be smaller & easier?



(Yes, I know it should be "cells" rather than "batteries".)

Thanks.

It's simpler, change one battery rather than six.

It's generally cheaper, or rather, the outlay at a given time is less with
a 9v battery, though of course you probably buy batteries more often.

Less space is required, which might be a factor.

Take one of the old 27MHz license free walkie talkies, that all ran off
9v. If they'd used 6 AA batteries, They'd either have to make the case
longer or wider to fit those extra batteries, and even if the per unit
cost is tiny, it adds up over the production run. Likewise the 9v battery
needs just the connector, while AA need a battery holder.

There were 9v batteries before transistor radios, though bigger units if I
get the picture properly. Then transistor radios came along, and they
added the 9v battery. For lots of things, it's not optimum, but it's
cheaper. You can buy little caps that fit onto 9v batteries to add a
switch and an LED bulb, nice little flashlights. 9v is overkill, but you
need more than one 1.5V battery to light the LED, so the 9v battery is
simpler and cheaper.

Michael

 

[Adam Funk]

On 2015-05-05, mroberds@att.net wrote:

Adam Funk <a24061@ducksburg.com> wrote:
As I was putting this together, I realized that 6 AAs in series make
about 9 V, so I'm wondering why a toy would run on 6 AAs when 1 9V
would be smaller & easier?

As has been mentioned, 6 AA cells have a lot more capacity than one 9 V
battery. To put some numbers on it:

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/NA_DATASHEETS/MN1500_US_CT.pdf

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/NA_DATASHEETS/MN1604_6LF22_US_CT.pdf

Look at the first graph in both data sheets. At a constant 10 mA load,
the 9 V will last about 60 hours, while the stack of AAs will last about
320 hours; the AAs last 5.3x as long. In the second graph, at a
constant 100 mA, the 9 V is good for 3 hours, while the AAs are good for
about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and about
22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4 cm^3.

Yes,that makes sense. And the weight is clearly related to the
energy, related to the amount of "stuff" in an alkaline cell.

Looking at pricing, Wal-Mart sells a two-pack of Rayovac 9 V batteries
for $5.47, or $2.735 each. They sell a 4-pack of Rayovac AAs for $2.97
($0.743 each) or an 8-pack for $4.97 ($0.621 each). This makes a string
of 6 AAs cost something around $3.73 to $4.46; more expensive than the
9 V battery, but also better performance.

Interesting. Thanks (& to everyone else) for the information.


--
Classical Greek lent itself to the promulgation of a rich culture,
indeed, to Western civilization. Computer languages bring us
doorbells that chime with thirty-two tunes, alt.sex.bestiality, and
Tetris clones. (Stoll 1995)

 

[Tim Wescott]

On Tue, 05 May 2015 19:06:59 +0000, mroberds wrote:

Adam Funk <a24061@ducksburg.com> wrote:
As I was putting this together, I realized that 6 AAs in series make
about 9 V, so I'm wondering why a toy would run on 6 AAs when 1 9V
would be smaller & easier?

As has been mentioned, 6 AA cells have a lot more capacity than one 9 V
battery. To put some numbers on it:

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/
NA_DATASHEETS/MN1500_US_CT.pdf

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/
NA_DATASHEETS/MN1604_6LF22_US_CT.pdf

Look at the first graph in both data sheets. At a constant 10 mA load,
the 9 V will last about 60 hours, while the stack of AAs will last about
320 hours; the AAs last 5.3x as long. In the second graph, at a
constant 100 mA, the 9 V is good for 3 hours, while the AAs are good for
about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and about
22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4 cm^3.

Do the math, and you see that the capacity/weight tradeoff is better for
AA than 9V, too. I realize that you'd need to redo the computations with
constant power rather than constant current, but I suspect the AA cells
will still come out ahead most of the time.

For a new-equipment design, I'd lean toward a pair of AA cells and a boost
regulator, unless there's some really compelling reason not to.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Tom Biasi]

On 5/5/2015 4:37 PM, Tim Wescott wrote:

On Tue, 05 May 2015 19:06:59 +0000, mroberds wrote:

Adam Funk <a24061@ducksburg.com> wrote:
As I was putting this together, I realized that 6 AAs in series make
about 9 V, so I'm wondering why a toy would run on 6 AAs when 1 9V
would be smaller & easier?

As has been mentioned, 6 AA cells have a lot more capacity than one 9 V
battery. To put some numbers on it:

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/
NA_DATASHEETS/MN1500_US_CT.pdf

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/
NA_DATASHEETS/MN1604_6LF22_US_CT.pdf

Look at the first graph in both data sheets. At a constant 10 mA load,
the 9 V will last about 60 hours, while the stack of AAs will last about
320 hours; the AAs last 5.3x as long. In the second graph, at a
constant 100 mA, the 9 V is good for 3 hours, while the AAs are good for
about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and about
22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4 cm^3.


For a new-equipment design, I'd lean toward a pair of AA cells and a boost
regulator, unless there's some really compelling reason not to.

Like if the toy has a motor?

 

[Ralph Mowery]

<mroberds@att.net> wrote in message news:mib4ch$m36$1@dont-email.me...

Look at the first graph in both data sheets. At a constant 10 mA load,
the 9 V will last about 60 hours, while the stack of AAs will last about
320 hours; the AAs last 5.3x as long. In the second graph, at a
constant 100 mA, the 9 V is good for 3 hours, while the AAs are good for
about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and about
22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4 cm^3.

Looking at pricing, Wal-Mart sells a two-pack of Rayovac 9 V batteries
for $5.47, or $2.735 each. They sell a 4-pack of Rayovac AAs for $2.97
($0.743 each) or an 8-pack for $4.97 ($0.621 each). This makes a string
of 6 AAs cost something around $3.73 to $4.46; more expensive than the
9 V battery, but also better performance.

Years ago the 9 volts were made of flat cellsand not in much of a case.
Later they were made of what looks like AAA cells or so. I have not opened
one up in a while, so don't know what they look like now.

 

[John Fields]

On Tue, 5 May 2015 10:46:15 -0700 (PDT), jurb6006@gmail.com wrote:

"As well as being way cheaper per amp-hour. "

HAHA.

Got these elcheapo meters from Harbor Freight. At one time they were on sale for like $3.99. I looked at a nine volt battery in the store and it was $4.99.

Actually if you can grab their coupons, they actually give these meters away for free sometimes. Meter = free. Battery = ridiculous.

---
And all that bluster has what to do with the capacity of a 9 volt
battery made from 1.5 volt AA cells VS the capacity of your
garden-variety 9 volt prismatic battery?

John Fields

 

[John Fields]

On Tue, 5 May 2015 17:30:14 -0400, "Ralph Mowery"
<rmowery28146@earthlink.net> wrote:

mroberds@att.net> wrote in message news:mib4ch$m36$1@dont-email.me...
Look at the first graph in both data sheets. At a constant 10 mA load,
the 9 V will last about 60 hours, while the stack of AAs will last about
320 hours; the AAs last 5.3x as long. In the second graph, at a
constant 100 mA, the 9 V is good for 3 hours, while the AAs are good for
about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and about
22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4 cm^3.

Looking at pricing, Wal-Mart sells a two-pack of Rayovac 9 V batteries
for $5.47, or $2.735 each. They sell a 4-pack of Rayovac AAs for $2.97
($0.743 each) or an 8-pack for $4.97 ($0.621 each). This makes a string
of 6 AAs cost something around $3.73 to $4.46; more expensive than the
9 V battery, but also better performance.


Years ago the 9 volts were made of flat cellsand not in much of a case.
Later they were made of what looks like AAA cells or so. I have not opened
one up in a while, so don't know what they look like now.

---
Thanks, Ralph, posting what you're clueless about is ever so
helpful.

John Fields

 

[Tim Wescott]

On Tue, 05 May 2015 17:00:52 -0400, Tom Biasi wrote:

On 5/5/2015 4:37 PM, Tim Wescott wrote:
On Tue, 05 May 2015 19:06:59 +0000, mroberds wrote:

Adam Funk <a24061@ducksburg.com> wrote:
As I was putting this together, I realized that 6 AAs in series make
about 9 V, so I'm wondering why a toy would run on 6 AAs when 1 9V
would be smaller & easier?

As has been mentioned, 6 AA cells have a lot more capacity than one 9
V battery. To put some numbers on it:

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/
NA_DATASHEETS/MN1500_US_CT.pdf

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/
NA_DATASHEETS/MN1604_6LF22_US_CT.pdf

Look at the first graph in both data sheets. At a constant 10 mA
load, the 9 V will last about 60 hours, while the stack of AAs will
last about 320 hours; the AAs last 5.3x as long. In the second graph,
at a constant 100 mA, the 9 V is good for 3 hours, while the AAs are
good for about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and
about 22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4
cm^3.


For a new-equipment design, I'd lean toward a pair of AA cells and a
boost regulator, unless there's some really compelling reason not to.

Like if the toy has a motor?

Way high production products have different economies than most of what I
work on.

If the toy has a motor then I'd lean toward a 3V motor instead of a 9V
motor, running straight off the batteries.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

Tim Wescott <seemywebsite@myfooter.really> wrote:

On Tue, 05 May 2015 19:06:59 +0000, mroberds wrote:

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/NA_DATASHEETS/MN1500_US_CT.pdf

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/NA_DATASHEETS/MN1604_6LF22_US_CT.pdf

I realize that you'd need to redo the computations with constant power
rather than constant current, but I suspect the AA cells will still
come out ahead most of the time.

The Duracell data sheets have curves for constant power, constant
resistance, and even constant temperature. I just grabbed the constant
current numbers because that was the first chart in both sheets.

For a new-equipment design, I'd lean toward a pair of AA cells and a
boost regulator, unless there's some really compelling reason not to.

Availability is another factor, too. If you go to the general store,
AAs are available in everything from 4 packs up to 20 packs or more, and
they have a lot of them. 9 V batteries come in 1, 2, or 4 packs, and
they have some. D batteries come in 4 or 8 and they have some. C
batteries come in 2 or 4 packs, but they don't stock many of them.

As a user, I like designs that use AA cells. If it doesn't take much
juice at all, or I don't think I'll use it often, I'll put primary
cell(s) in there. If it takes a lot, I can often run NiMHs, but still
have the option of using primary cells if I am caught short.

Matt Roberds

 

[Michael Black]

On Tue, 5 May 2015, John Fields wrote:

On Tue, 5 May 2015 10:46:15 -0700 (PDT), jurb6006@gmail.com wrote:

"As well as being way cheaper per amp-hour. "

HAHA.

Got these elcheapo meters from Harbor Freight. At one time they were on sale for like $3.99. I looked at a nine volt battery in the store and it was $4.99.

Actually if you can grab their coupons, they actually give these meters away for free sometimes. Meter = free. Battery = ridiculous.

---
And all that bluster has what to do with the capacity of a 9 volt
battery made from 1.5 volt AA cells VS the capacity of your
garden-variety 9 volt prismatic battery?

Maybe he was suggesting getting the meter for free with the coupon, and
then using the 9v battery in something else.

I was suprised a couple of years ago to find that the cheap DMM I bought
at the hardware chain store here used a 9v battery. "Everyone knows a DMM
should use AA batteries".

Michael

 

[Michael Black]

On Tue, 5 May 2015, Ralph Mowery wrote:

mroberds@att.net> wrote in message news:mib4ch$m36$1@dont-email.me...
Look at the first graph in both data sheets. At a constant 10 mA load,
the 9 V will last about 60 hours, while the stack of AAs will last about
320 hours; the AAs last 5.3x as long. In the second graph, at a
constant 100 mA, the 9 V is good for 3 hours, while the AAs are good for
about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and about
22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4 cm^3.

Looking at pricing, Wal-Mart sells a two-pack of Rayovac 9 V batteries
for $5.47, or $2.735 each. They sell a 4-pack of Rayovac AAs for $2.97
($0.743 each) or an 8-pack for $4.97 ($0.621 each). This makes a string
of 6 AAs cost something around $3.73 to $4.46; more expensive than the
9 V battery, but also better performance.


Years ago the 9 volts were made of flat cellsand not in much of a case.
Later they were made of what looks like AAA cells or so. I have not opened
one up in a while, so don't know what they look like now.

I wasn't sure if that was a transition, or just different companies doing
things differently.

Yes, I remember the stack of cells and then about 20 or 25 years ago
taking a 9v battery apart for something, and finding the "AAA" batteries
inside. But I wasn't taking apart a lot of 9v batteries, so I wasn't sure
if there was a pattern or not.

Michael

 

[Bob Masta]

On Tue, 05 May 2015 20:56:19 +0100, Adam Funk
<a24061@ducksburg.com> wrote:

On 2015-05-05, mroberds@att.net wrote:

Adam Funk <a24061@ducksburg.com> wrote:
As I was putting this together, I realized that 6 AAs in series make
about 9 V, so I'm wondering why a toy would run on 6 AAs when 1 9V
would be smaller & easier?

As has been mentioned, 6 AA cells have a lot more capacity than one 9 V
battery. To put some numbers on it:

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/NA_DATASHEETS/MN1500_US_CT.pdf

http://ww2.duracell.com/media/en-US/pdf/gtcl/Product_Data_Sheet/NA_DATASHEETS/MN1604_6LF22_US_CT.pdf

Look at the first graph in both data sheets. At a constant 10 mA load,
the 9 V will last about 60 hours, while the stack of AAs will last about
320 hours; the AAs last 5.3x as long. In the second graph, at a
constant 100 mA, the 9 V is good for 3 hours, while the AAs are good for
about 27 hours; the AAs last 9x as long.

You do pay for it in weight and size; the 9 V battery is 45 g and about
22.8 cm^3, and the 6 AAs will be about 144 g and about 50.4 cm^3.

Yes,that makes sense. And the weight is clearly related to the
energy, related to the amount of "stuff" in an alkaline cell.


Looking at pricing, Wal-Mart sells a two-pack of Rayovac 9 V batteries
for $5.47, or $2.735 each. They sell a 4-pack of Rayovac AAs for $2.97
($0.743 each) or an 8-pack for $4.97 ($0.621 each). This makes a string
of 6 AAs cost something around $3.73 to $4.46; more expensive than the
9 V battery, but also better performance.

Interesting. Thanks (& to everyone else) for the information.

One thing (maybe the *only* thing) in favor of 9V batteries
is that their snap-in contact system seems to be much more
reliable than that of standard cylindrical cells, especially
chains of cells.

(This may be an unfair comparison, since 9V batteries are
usually only found in low-current applications, and it may
be that the higher current in the multi-cell products is the
culprit causing the terminal corrosion.)

Best regards,


Bob Masta

DAQARTA v7.60
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusiq generator
Science with your sound card!

 

[Ralph Mowery]

"Michael Black" <et472@ncf.ca> wrote in message
news:alpine.LNX.2.02.1505060232090.14480@darkstar.example.org...

Maybe he was suggesting getting the meter for free with the coupon, and
then using the 9v battery in something else.

I was suprised a couple of years ago to find that the cheap DMM I bought
at the hardware chain store here used a 9v battery. "Everyone knows a DMM
should use AA batteries".

Maybe my Fluke meter is not any good because it uses a 9 volt battery.
Guess that I should ask for my $ 350 back.

 

[John Fields]

On Wed, 6 May 2015 10:58:28 -0400, "Ralph Mowery"
<rmowery28146@earthlink.net> wrote:

"Michael Black" <et472@ncf.ca> wrote in message
news:alpine.LNX.2.02.1505060232090.14480@darkstar.example.org...
Maybe he was suggesting getting the meter for free with the coupon, and
then using the 9v battery in something else.

I was suprised a couple of years ago to find that the cheap DMM I bought
at the hardware chain store here used a 9v battery. "Everyone knows a DMM
should use AA batteries".



Maybe my Fluke meter is not any good because it uses a 9 volt battery.
Guess that I should ask for my $ 350 back.

---
I think Michael Black's comment was supposed to be joke-ish since -
as far as I know - all battery-operated DMMs are powered by 9V
batteries.

Do you know of any exceptions which use AAs?

John Fields