AA battary capacity, Ah (?)

[Bob Kos]

Right on the money. Heat kills batteries. Cheap chargers overheat the
batteries. The Maha chargers work nice for reasonable cost. I have NiMH
batteries that still work well after 5 years thanks to the TLC they get in
my cheapie Maha charger. Thomas Distributing is the place to get 'em.

Speaking of heat, you should use caution in using lithium AA throwaway
batteries. They apparently get quite hot during heavy discharge cycles. So
much so that my Olympus D-600L's warranty would be voided if those batteries
were used in it.

Ted Edwards wrote in message <3F0C7BA5.2CF7@telus.net>...

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

Ted

 

[Old Nick]

On Fri, 11 Jul 2003 19:34:24 +0000 (UTC), davem@cs.ubc.ca (Dave
Martindale) wrote something
.......and in reply I say!:

PMFJI. You sound as if you are addressing the questions I have.

I have a couple of little Uniden walkie-talkies, that take 4 X AAA
cells. They chew out the cells fairly fast, so I bought NiCds. No go.
The radios appear to have trouble dealing with the lower voltage. I
reckon they are trying to grab max volts to get Tx power up, and
probably should have had an extra battery. Rechargeable ALkalines
worked fine, but as you say deteroriate rapidly.

Sorry. Question. Are NiMH cells better in this regard? I am ringing
battery houses, and one guy said they were. I assume this would be
because they have lower internal resistance. Is this so? I got the
impression the guy knew more about _batteries_ than I do, but less
about electrical theory <G>

Next <G>. One shop had several AH capacities, at different prices
(actually they were the only ones to explain this, and will get my
custom). Are there any advantages/disadvantages to getting the lower
capacities, if this means they get discharged better etc?

Thanks for any help. Sick of buying expensive "special" chargers that
then gather dust.

This is really just demonstrating that alkalines aren't suitable for
your digital camera - too much internal resistance.

******************************************************************************************
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
!!
<")
_/ )
( )
_//- \__/

 

[Dave Martindale]

nsnfwhite@iinet.net.au (Old Nick) writes:

I have a couple of little Uniden walkie-talkies, that take 4 X AAA
cells. They chew out the cells fairly fast, so I bought NiCds. No go.
The radios appear to have trouble dealing with the lower voltage. I
reckon they are trying to grab max volts to get Tx power up, and
probably should have had an extra battery. Rechargeable ALkalines
worked fine, but as you say deteroriate rapidly.

Sounds like the radio is poorly designed. Alkaline cells start at 1.5
volts, but drop pretty much continuously in voltage as they are drained.
Depending on the load, a device needs to operate properly down to 1 V
per cell (light load) to 0.8 V per cell (heavy load) in order to get
most of the energy out of alkalines. So a properly-designed radio
powered by 4 alkaline cells should tolerate 6 V in, but work properly
all the way down to 4 V. NiCd and NiMH cells provide about 1.2 V over
nearly their entire discharge time, over a wide range of load. Thus,
4 cells will provide 4.8 V and the radio *should* work fine.

If the radio doesn't work on NiCds, and the NiCds were in fact all good,
then it just doesn't operate properly at 4.8 V. If it works at 6 V but
not at 4.8 V, it will start working OK on alkalines, but stop working
when the alkalines are still half-full.

Sorry. Question. Are NiMH cells better in this regard? I am ringing
battery houses, and one guy said they were. I assume this would be
because they have lower internal resistance. Is this so? I got the
impression the guy knew more about _batteries_ than I do, but less
about electrical theory <G

NiMH is not better than NiCd in this respect. NiMH actually have higher
internal resistance than NiCd, though still far below alkalines. If
NiCds don't work, NiMH aren't likely to either.

Next <G>. One shop had several AH capacities, at different prices
(actually they were the only ones to explain this, and will get my
custom). Are there any advantages/disadvantages to getting the lower
capacities, if this means they get discharged better etc?

Lower capacity cells may just be older. But they may also have lower
internal resistance. You can't really tell without measuring. I
wouldn't pay much of a premium for exceptionally high capacity.

Dave

 

[jakdedert]

All the Motorola FRS radios (that I'm familiar with) use three AA cells.
All of their literature states that alkalines or Nimhs *must* be used.
According to Motorola, NiCads are not acceptable.

jak

"Dave Martindale" <davem@cs.ubc.ca> wrote in message
news:benk0e$dmo$1@mughi.cs.ubc.ca...

nsnfwhite@iinet.net.au (Old Nick) writes:

I have a couple of little Uniden walkie-talkies, that take 4 X AAA
cells. They chew out the cells fairly fast, so I bought NiCds. No go.
The radios appear to have trouble dealing with the lower voltage. I
reckon they are trying to grab max volts to get Tx power up, and
probably should have had an extra battery. Rechargeable ALkalines
worked fine, but as you say deteroriate rapidly.

Sounds like the radio is poorly designed. Alkaline cells start at 1.5
volts, but drop pretty much continuously in voltage as they are drained.
Depending on the load, a device needs to operate properly down to 1 V
per cell (light load) to 0.8 V per cell (heavy load) in order to get
most of the energy out of alkalines. So a properly-designed radio
powered by 4 alkaline cells should tolerate 6 V in, but work properly
all the way down to 4 V. NiCd and NiMH cells provide about 1.2 V over
nearly their entire discharge time, over a wide range of load. Thus,
4 cells will provide 4.8 V and the radio *should* work fine.

If the radio doesn't work on NiCds, and the NiCds were in fact all good,
then it just doesn't operate properly at 4.8 V. If it works at 6 V but
not at 4.8 V, it will start working OK on alkalines, but stop working
when the alkalines are still half-full.

Sorry. Question. Are NiMH cells better in this regard? I am ringing
battery houses, and one guy said they were. I assume this would be
because they have lower internal resistance. Is this so? I got the
impression the guy knew more about _batteries_ than I do, but less
about electrical theory <G

NiMH is not better than NiCd in this respect. NiMH actually have higher
internal resistance than NiCd, though still far below alkalines. If
NiCds don't work, NiMH aren't likely to either.

Next <G>. One shop had several AH capacities, at different prices
(actually they were the only ones to explain this, and will get my
custom). Are there any advantages/disadvantages to getting the lower
capacities, if this means they get discharged better etc?

Lower capacity cells may just be older. But they may also have lower
internal resistance. You can't really tell without measuring. I
wouldn't pay much of a premium for exceptionally high capacity.

Dave

 

[Dave Martindale]

"jakdedert" <jdedert@bellsouth.net> writes:

All the Motorola FRS radios (that I'm familiar with) use three AA cells.
All of their literature states that alkalines or Nimhs *must* be used.
According to Motorola, NiCads are not acceptable.

That's not true of the T6210. In the battery installation section, it
just says "AA batteries" or a special NiMH pack sold by Motorola. It
doesn't specify what kind of AA batteries.

Later in the manual, it describes how you can change the battery meter
voltage thresholds. The two settings are "A" for alkaline and "n" for
"NiMH or NiCad rechargeable". That's a direct quote from the manual.
So it's clearly intended to work with NiCd cells.

The Motorola NiMH pack is somewhat weird - its capacity is only 550 mAH.
I wonder if they use 4 AAA cells in it to get 4.8 V for higher transmit
power (but short battery life). It also has contacts that mate with
charging contacts on the battery compartment cover, which in turn mate
with contacts on the Motorola charger. This ensures that only the
Motorola rechargeable pack can be charged inside the radio.

Dave

 

[Ted Edwards]

lcoe wrote:

Ted, or anyone, i bot a RShack "Auto Sensing" model (for ni-cad and lithium).
the manual and box says, "automatically senses full charge and shuts off".
further, in the manual it says, '`...charge only fully discharged cells...'

I replied to this but don't see it and my ISP has been having the
nasties so:

I wouldn't trust it but YMMV. First off, they don't mention delt-V
termination or NiMH. Second, there should be no need to fully discharge
cells before charging if it were truly a smart charger.

another feature is a "backup" fixed timer, 1.5hr for nicad, 2.0 for lith.
it's RS model 23-405, 50% off recently. it's heavy, brick shaped, but
is it really fully automatic?

I don't think so and wouldn't trust it but I haven't personally seen
it. I *know* the Maha's are good.

Ted

 

[Sofie]

Old Nick......
Adding the extra NiCad cell as you suggested will give you a total of 4.8
V.... very close to what 3 fresh alkaline batteries will put out. An
eloquent solution that I have seen in some consumer equipment over the years
is to use (2) AAA cells and (2) 1/2AAA cells. The 1/2 cells obviously
won't have the capacity of a larger full size AAA cell, but the radio will
operate correctly with the voltage boost....... and all the batteries can
fit in the radio's battery compartment without the need for "ugly"
modifications and "add ons".
The "half" cells in the AAA size can be difficult to find but they are
available.......
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
-----------------------------

 

[jakdedert]

I'm sorry. I've got so many of these--of several different models--that I
can't pull up just where I saw that info. I checked to be sure, because I
have NiCds I could be using. Nimh's work great, and alkaline usage is
acceptable...unless I have a crew of 11 guys all trying to keep in touch.
Then I go through a case of them in a week or so.

I'm sure I saw this info somewhere...it may have been one particular model.
The 280 manual (only one which I was able to put my hands on easily) doesn't
mention NiCd's at all...just rechargeable alk's. We've got 280's, 250's,
6220's, FR-60's--among others.

jak

"Dave Martindale" <davem@cs.ubc.ca> wrote in message
news:beoaro$j5n$1@mughi.cs.ubc.ca...

"jakdedert" <jdedert@bellsouth.net> writes:
All the Motorola FRS radios (that I'm familiar with) use three AA cells.
All of their literature states that alkalines or Nimhs *must* be used.
According to Motorola, NiCads are not acceptable.

That's not true of the T6210. In the battery installation section, it
just says "AA batteries" or a special NiMH pack sold by Motorola. It
doesn't specify what kind of AA batteries.

Later in the manual, it describes how you can change the battery meter
voltage thresholds. The two settings are "A" for alkaline and "n" for
"NiMH or NiCad rechargeable". That's a direct quote from the manual.
So it's clearly intended to work with NiCd cells.

The Motorola NiMH pack is somewhat weird - its capacity is only 550 mAH.
I wonder if they use 4 AAA cells in it to get 4.8 V for higher transmit
power (but short battery life). It also has contacts that mate with
charging contacts on the battery compartment cover, which in turn mate
with contacts on the Motorola charger. This ensures that only the
Motorola rechargeable pack can be charged inside the radio.

Dave

 

[Eastburn]

Remember - NiCad are 1.25 volts per cell. To low for some electronics
to function when in a higher voltage circuit.

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer oldtree@pacbell.net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

 

[lcoe]

In rec.crafts.metalworking Eastburn <oldtree@pacbell.net> wrote:

Remember - NiCad are 1.25 volts per cell. To low for some electronics
to function when in a higher voltage circuit. > Martin

1.2, right? also, i now find that the NiMH are also 1.2(!). --Loren

--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer oldtree@pacbell.net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

 

[GregS]

In article <bf1jbh$f0q$2@mughi.cs.ubc.ca>, davem@cs.ubc.ca (Dave Martindale) wrote:

Eastburn <oldtree@pacbell.net> writes:
Remember - NiCad are 1.25 volts per cell. To low for some electronics
to function when in a higher voltage circuit.

It's actually easier to design circuits to work properly on NiCd and
NiMh, since the voltage is close to 1.2 V per cell for almost the entire
discharge life of the cell.

In comparison, alkaline cells deliver 1.5 V when new but drop to 1.0 V
or less at end of life (depending on current). Any device that wants to
use alkaline cells should be designed to operate all the way down to 1 V

Forgot to mention high output current where Nicad is king, Nimh second, and
alkaline third. An alkaline will output perhaps 1.2 volts or less at high current.
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.

greg

 

[Dave Martindale]

szekeres@pitt.edu (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

 

[jakdedert]

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" <davem@cs.ubc.ca> wrote in message
news:bf1n86$g5p$1@mughi.cs.ubc.ca...

szekeres@pitt.edu (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

 

[CMF]

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" <jdedert@bellsouth.net> wrote in message
news:27%Qa.177$8h2.159@fe04.atl2.webusenet.com...

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" <davem@cs.ubc.ca> wrote in message
news:bf1n86$g5p$1@mughi.cs.ubc.ca...
szekeres@pitt.edu (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

 

[Venger]

"Eastburn" <oldtree@pacbell.net> wrote in message
news:3F1391E3.5BC54ED4@pacbell.net...

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

 

[Dave Martindale]

"CMF" <maury@HAMNOTSPAMcmf-enterprises.com> 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

 

[CMF]

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" <davem@cs.ubc.ca> wrote in message
news:bf4b66$4vo$1@mughi.cs.ubc.ca...

"CMF" <maury@HAMNOTSPAMcmf-enterprises.com> 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

 

[Rex B]

|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.

 

[Old Nick]

On Tue, 15 Jul 2003 19:06:25 +0000 (UTC), davem@cs.ubc.ca (Dave
Martindale) wrote something
.......and in reply I say!:

Sigh! <G> As the starter of this portion of the thread, I must remind
you they _are_ Uniden :-< They seemed like a good idea at the time.

In other words, it's a
piece of junk.

******************************************************************************************
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
!!
<")
_/ )
( )
_//- \__/

 

[Old Nick]

On Mon, 14 Jul 2003 15:27:05 -0700, "Sofie" <sofie@olypen.com> 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" <nsnfwhite@iinet.net.au> wrote in message
news:3f11e736.149455491@news.iinet.net.au...
On Sat, 12 Jul 2003 17:34:37 -0700, "Sofie" <sofie@olypen.com> 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
!!
<")
_/ )
( )
_//- \__/