Olympus C740UZ - NIMH AA Specs - Whats the meaning ?

My Olympus C740UZ uses 4 AA's as well as an AC Adapter rated at 6.5 Volts 2
A. Alkaline AA's are 1.5 volts they don't specify Amperage. HIMH's are
usually 1.2 Volts or 1.25 Volts with Amps 1400 mah to 2500 mah.

As mentioned above, my AC Adapter is rated at 2 amps output. Is this the
same as 2000 mah (is mah milliamps per hour ?).

So my camera apparently is OK operating at between 4.8 volts and 6.5 volts.
What amperage is acceptable or best, I have no clue.

How does one sort this technical mud out. What NIMH AA's are best ? Longest
lasting charge? Longest life ? Does rapid charging wear them out faster ?
One of my chargers is a 4 hr charger (4 AA's) and the other is a 7 hr
charger for 4 AA's

I'm fairly tech savy in general - deg in computer programming - I've
recently tried to shop for NIMH batteries and chargers and I can't
help but get the feeling that coprporate america's answer to the
availability of information is to drown you with a sea of generalized
unclear information with the goal of getting you to purchase products that
don't really meet your needs so that you will wind up making several
purchases since with the confusing information you are unlikely to purchase
what you really want/need the first time.

I'm inclined to think that there is little consumer protection as far as
requiring manufacturers to provide clear understandable information. I don't
think this is an accident.

"dave" wrote in message
ink.net...
My Olympus C740UZ uses 4 AA's as well as an AC Adapter rated at 6.5 Volts
2
A. Alkaline AA's are 1.5 volts they don't specify Amperage. HIMH's are
usually 1.2 Volts or 1.25 Volts with Amps 1400 mah to 2500 mah.

As mentioned above, my AC Adapter is rated at 2 amps output. Is this the
same as 2000 mah (is mah milliamps per hour ?).

So my camera apparently is OK operating at between 4.8 volts and 6.5
volts.
What amperage is acceptable or best, I have no clue.

How does one sort this technical mud out. What NIMH AA's are best ?
Longest
lasting charge? Longest life ? Does rapid charging wear them out faster ?
One of my chargers is a 4 hr charger (4 AA's) and the other is a 7 hr
charger for 4 AA's

I'm fairly tech savy in general - deg in computer programming - I've
recently tried to shop for NIMH batteries and chargers and I can't
help but get the feeling that coprporate america's answer to the
availability of information is to drown you with a sea of generalized
unclear information with the goal of getting you to purchase products that
don't really meet your needs so that you will wind up making several
purchases since with the confusing information you are unlikely to
purchase
what you really want/need the first time.

I'm inclined to think that there is little consumer protection as far as
requiring manufacturers to provide clear understandable information. I
don't
think this is an accident.


With the price of batteries at $ 2 each why worry much about it. You may
spend $ 20 for them over a year or two.

The higher the miliamp hour rating , the longer they will last before
recharging. You can not equate the charger with the battery ratings. The
camera will use a very small ammount of current tuil you press the button
that takes the pix. When that hapens you need a very high burst of current
for about a second.
The rating of the charger at 2 amps is the maximum of how much it can put
out. The rating of the batteries is how much plus the time they can put out
current. For one rated for 1000 mha means it can put out 1000 ma for one
hour. If the current is doubled to 2000 ma, the battery will only last 1/2
hour. In use the camera will use maybe 50 to 100 ma most of the time and
then a couple of thousand ma for about one second. Hard to really tell how
long the batteries will last but the book of the cam may have a typical
number of pix you can take provided you take them in a short period of time
and if the lcd display is used or not.

As to charging times , if the charger is rated for the batteries the
charging time will not mater that much.

Just buy 2 or 3 sets and don't worry about it.
They will run down in a few weeks if they are used or not so recharge them a
day or so before you are planning on using them.

dave wrote:
My Olympus C740UZ uses 4 AA's as well as an AC Adapter rated at 6.5 Volts 2
A. Alkaline AA's are 1.5 volts they don't specify Amperage. HIMH's are
usually 1.2 Volts or 1.25 Volts with Amps 1400 mah to 2500 mah.

As mentioned above, my AC Adapter is rated at 2 amps output. Is this the
same as 2000 mah (is mah milliamps per hour ?).

So my camera apparently is OK operating at between 4.8 volts and 6.5 volts.
What amperage is acceptable or best, I have no clue.

How does one sort this technical mud out. What NIMH AA's are best ? Longest
lasting charge? Longest life ? Does rapid charging wear them out faster ?
One of my chargers is a 4 hr charger (4 AA's) and the other is a 7 hr
charger for 4 AA's

I'm fairly tech savy in general - deg in computer programming - I've
recently tried to shop for NIMH batteries and chargers and I can't
help but get the feeling that coprporate america's answer to the
availability of information is to drown you with a sea of generalized
unclear information with the goal of getting you to purchase products that
don't really meet your needs so that you will wind up making several
purchases since with the confusing information you are unlikely to purchase
what you really want/need the first time.

I'm inclined to think that there is little consumer protection as far as
requiring manufacturers to provide clear understandable information. I don't
think this is an accident.

Hi Dave...

The output of your adaptor is 2 amps. Continuously,
or virtually forever.

Your 2000mah (2ah) batteries will deliver 2 amps for
one hour. Or any derivative of that - ie 4 amps for
1/2 hour. Or 1 amp for 2 hours. Any combination,
that is, until we run into the dreaded reciprocity
failure

A voltage regulator in your camera pulls the voltage
down to its design requirement. That is, when your
adaptor is in use, the camera itself reduces that
to 4.8 volts. Incidentally, it's the voltage drop
across the regulator that determines the battery
condition for the battery display, and to shut it off
when it finally gets too low.

mah = mils per hour. Buy the best that you can find and
that your budget allows.

It's my personal opinion that the faster you charge
them the lower their lifespan you should expect.
If you wanna charge them in 15 minutes, they will get
hot, and there's a price to be paid for that.
Others may disagree with me.


If you buy more than one set (and sooner or later you
will) then mark them as a set. Use them as a set,
charge them as a set.

Finally, treat them with the greatest of respect.
Their internal impedance is so low that they'll
happily dump their entire charge in just a few
seconds. They get incredibly hot incredibly fast.
I've had a burn mark on my leg for several years now
just for having put a set of them loose in a blue jeans
pocket. If you're lucky enough to have youngsters
in your life, keep the youngsters and batteries
well separated.

Hope this helps - or at least get your started.

Ken

"dave" wrote in message
ink.net...
My Olympus C740UZ uses 4 AA's as well as an AC Adapter rated at 6.5 Volts
2
A. Alkaline AA's are 1.5 volts they don't specify Amperage. HIMH's are
usually 1.2 Volts or 1.25 Volts with Amps 1400 mah to 2500 mah.

As mentioned above, my AC Adapter is rated at 2 amps output. Is this the
same as 2000 mah (is mah milliamps per hour ?).

It would be yes, but the 2A rating is *maximum* - the camera would only use
the full 2A at rare times when its doing 'everything' at once.


So my camera apparently is OK operating at between 4.8 volts and 6.5
volts.
What amperage is acceptable or best, I have no clue.

'apparently' may be a dangerous assumption. The 6.5V is probably internally
regulated down to ~5V (and then probably stepped up/down for other voltages
like 5,3.3,12... maybe others too)

How does one sort this technical mud out. What NIMH AA's are best ?
Longest
lasting charge? Longest life ?

Once you get beyond about 2000mAh your getting into somewhat unknown
territory with NiMh's - they may quote figures like 2400mAh, but there's no
telling if they will provide that on the irregular-style discharge pattern
camera and similar items take.

Does rapid charging wear them out faster ?
One of my chargers is a 4 hr charger (4 AA's) and the other is a 7 hr
charger for 4 AA's

Are these NhMh chargers or NiCd chargers? Timer or charge sensing? Remember
that NiMh's really need a different charger to NiCad's to ensure the
_maximum_ life out of them. (Without getting to technical; NiCad's have a
nice voltage peak/drop at the point of full charge which is easy to detect,
whereas NhMh's have a much smaller peak and instead of a voltage drop after
full charge they just get hotter)

That said, NhMh's are still a developing technology - as yet nobody really
knows exactly what is the best way to ensure long life. NiMh's don't seem to
like trickle charge (14hours+ charge time) as it seems to shorten the total
life, fast charging (less than a few hours) also is fraught with the risks
of overcharging and reducing the life/capacity quickly. Best way at the
moment seem to be just to charge them on a 5-10 hour charge current and hope
for the best. You're pretty much guaranteed to get about 500 charge cycles
before the capacity starts to drop off, and most people seem to then get
another 500-1000+ cycles before they become useless.


I'm fairly tech savy in general - deg in computer programming - I've
recently tried to shop for NIMH batteries and chargers and I can't
help but get the feeling that coprporate america's answer to the
availability of information is to drown you with a sea of generalized
unclear information with the goal of getting you to purchase products that
don't really meet your needs so that you will wind up making several
purchases since with the confusing information you are unlikely to
purchase
what you really want/need the first time.

You have a degree in computer programming and you say:

drown you with a sea of generalized unclear information with the
goal of getting you to purchase products that don't really meet your needs

- irony at its best.

....

I don't think the industry is trying to put something over on you at
all. Its obvious most digital cameras will eat regular AA's at a
disturbing rate and the greater amperage (current) available from the
Nimh rechargables last a lot longer. Which brand is best ?? What does
it matter how they work if they work ??

dave wrote:
My Olympus C740UZ uses 4 AA's as well as an AC Adapter rated at 6.5 Volts 2
A. Alkaline AA's are 1.5 volts they don't specify Amperage. HIMH's are
usually 1.2 Volts or 1.25 Volts with Amps 1400 mah to 2500 mah.

As mentioned above, my AC Adapter is rated at 2 amps output. Is this the
same as 2000 mah (is mah milliamps per hour ?).

So my camera apparently is OK operating at between 4.8 volts and 6.5 volts.
What amperage is acceptable or best, I have no clue.

How does one sort this technical mud out. What NIMH AA's are best ? Longest
lasting charge? Longest life ? Does rapid charging wear them out faster ?
One of my chargers is a 4 hr charger (4 AA's) and the other is a 7 hr
charger for 4 AA's

I'm fairly tech savy in general - deg in computer programming - I've
recently tried to shop for NIMH batteries and chargers and I can't
help but get the feeling that coprporate america's answer to the
availability of information is to drown you with a sea of generalized
unclear information with the goal of getting you to purchase products that
don't really meet your needs so that you will wind up making several
purchases since with the confusing information you are unlikely to purchase
what you really want/need the first time.

I'm inclined to think that there is little consumer protection as far as
requiring manufacturers to provide clear understandable information. I don't
think this is an accident.

"dave" writes:
My Olympus C740UZ uses 4 AA's as well as an AC Adapter rated at 6.5 Volts 2
A. Alkaline AA's are 1.5 volts they don't specify Amperage. HIMH's are
usually 1.2 Volts or 1.25 Volts with Amps 1400 mah to 2500 mah.

As mentioned above, my AC Adapter is rated at 2 amps output. Is this the
same as 2000 mah (is mah milliamps per hour ?).

Not at all. mAh (note the capitalization is milliamps multiplied by
hours. A 2000 mAh battery will deliver 1 mA for 2000 hours, or 100 mA
for 20 hours, or 2 A for 1 hour (in theory; in practice capacity is less
at really high currents). The peak available output current for a NiMH
AA cell might be 10 A (10000 mA).

The rating on the AC adapter is peak output current, 2 A in this case.
It doesn't have a capacity rating, because its capacity is effectively
infinite as long as it's plugged into the wall. It will deliver 2000 mA
forever.

So my camera apparently is OK operating at between 4.8 volts and 6.5 volts.
What amperage is acceptable or best, I have no clue.

If the AC adapter is rated at 2 A, the camera will need nearly 2 A at
its peak (probably recharging the flash, writing to the memory card,
with the viewfinder on). But most of the time it will draw considerably
less.

Dave

I just bought 2 sets of 2 Panasonic NIMH AA's. All were yielding 1.2 Volts
as rated. I doubt they were just manufactured. In fact the 2 that came with
the charger was with the last charger on the shelf which would suggest that
it must have been on the shelf for some time. Just to double check, I put 2
in a flashlight and they were at full brightness as far as I could tell.
This would seem to suggest that they hold their charge I would think.

"Ralph Mowery" wrote in message
ink.net...

"dave" wrote in message
ink.net...
My Olympus C740UZ uses 4 AA's as well as an AC Adapter rated at 6.5
Volts
2
A. Alkaline AA's are 1.5 volts they don't specify Amperage. HIMH's are
usually 1.2 Volts or 1.25 Volts with Amps 1400 mah to 2500 mah.

As mentioned above, my AC Adapter is rated at 2 amps output. Is this the
same as 2000 mah (is mah milliamps per hour ?).

So my camera apparently is OK operating at between 4.8 volts and 6.5
volts.
What amperage is acceptable or best, I have no clue.

How does one sort this technical mud out. What NIMH AA's are best ?
Longest
lasting charge? Longest life ? Does rapid charging wear them out faster
?
One of my chargers is a 4 hr charger (4 AA's) and the other is a 7 hr
charger for 4 AA's

I'm fairly tech savy in general - deg in computer programming - I've
recently tried to shop for NIMH batteries and chargers and I can't
help but get the feeling that coprporate america's answer to the
availability of information is to drown you with a sea of generalized
unclear information with the goal of getting you to purchase products
that
don't really meet your needs so that you will wind up making several
purchases since with the confusing information you are unlikely to
purchase
what you really want/need the first time.

I'm inclined to think that there is little consumer protection as far as
requiring manufacturers to provide clear understandable information. I
don't
think this is an accident.


With the price of batteries at $ 2 each why worry much about it. You may
spend $ 20 for them over a year or two.

The higher the miliamp hour rating , the longer they will last before
recharging. You can not equate the charger with the battery ratings. The
camera will use a very small ammount of current tuil you press the button
that takes the pix. When that hapens you need a very high burst of
current
for about a second.
The rating of the charger at 2 amps is the maximum of how much it can put
out. The rating of the batteries is how much plus the time they can put
out
current. For one rated for 1000 mha means it can put out 1000 ma for one
hour. If the current is doubled to 2000 ma, the battery will only last
1/2
hour. In use the camera will use maybe 50 to 100 ma most of the time and
then a couple of thousand ma for about one second. Hard to really tell
how
long the batteries will last but the book of the cam may have a typical
number of pix you can take provided you take them in a short period of
time
and if the lcd display is used or not.

As to charging times , if the charger is rated for the batteries the
charging time will not mater that much.

Just buy 2 or 3 sets and don't worry about it.
They will run down in a few weeks if they are used or not so recharge them
a
day or so before you are planning on using them.

dave wrote:

I just bought 2 sets of 2 Panasonic NIMH AA's. All were yielding 1.2 Volts
as rated. I doubt they were just manufactured. In fact the 2 that came with
the charger was with the last charger on the shelf which would suggest that
it must have been on the shelf for some time. Just to double check, I put 2
in a flashlight and they were at full brightness as far as I could tell.
This would seem to suggest that they hold their charge I would think.

Hi Dave...

One more unique characteristic of the rechargable you're
going to experience

You'll hopefully remember in the good old days going
camping, or working on the car with a flashlight
and zinc-carbon batteries. First few nights, they're
fine. Then for the next few nights they're getting
dimmer. A few more nights of not bright enough but
better'n nothing. And on the last night still glowing
but just enough that if you hold it right against your
watch you can almost make out the time. Good memories

Anyway, because of the incredibly low internal impedance
of these nimh's, they dump all they've got until the
instant it's all gone. So it could well be that your
flashlight was indeed "full bright", but would have
been completely dead black in a matter of seconds,
or minutes.

The definitely do lose their charge quickly in
storage. Charge them just before you set off

Ken

"dave" wrote in message
.net...
So the AC adapter 2A is the max continuos output. whereas the the 2100 ma
is
the current that will be supplied in 1 hr which is also the total current
available. The available current could be yielded over a much longer or a
much shorter period of time depending on the rate od output. In other
words
if it were output at 21000 ma it would last 1/10 of an hour.

That's it. Although in practice both very high current drains (10's of
amps), and very low drains (less then a few mA) don't provide the capacity
you'd expect, for the normal range of use it applies just as you've
described it.

Also note that NiCads and NiMh's have quite a high self-discharge rate -
leave them fully charged doing nothing for a few weeks and they'll be down
to 50% or less of their capacity, so its best to charge them or at least top
them up for a few hours shortly before you need them for anything important.

....and while on the subject - you'll hear about whats known as the 'memory
effect' with NiCads - that's a (supposed) effect whereby if you repeatedly
discharge a battery to say 50%, then charge, discharge etc... the battery
develops a 'memory' and will then continue to provide only that capacity.
Lots of people would routinely discharge their batteries before charging to
avoid this issue.

Firstly, its not really much of a problem with NiCads used in cameras as the
discharge pattern is random enough to break any memory effect, secondly -
cycling the cells all the way down and up a couple of times breaks any
memory the cells may of developed, and thirdly - there's no evidence that
NiMh's *have* such a memory anyway! (but that said it was years before
anyone noticed it in NiCads...)

....

Thanks again, I'm ignorant of this stuff at this point.

"Ken Weitzel" wrote in message
news:IyQnd.287781$nl.159733@pd7tw3no...


dave wrote:

I just bought 2 sets of 2 Panasonic NIMH AA's. All were yielding 1.2
Volts
as rated. I doubt they were just manufactured. In fact the 2 that came
with
the charger was with the last charger on the shelf which would suggest
that
it must have been on the shelf for some time. Just to double check, I
put 2
in a flashlight and they were at full brightness as far as I could tell.
This would seem to suggest that they hold their charge I would think.

Hi Dave...

One more unique characteristic of the rechargable you're
going to experience

You'll hopefully remember in the good old days going
camping, or working on the car with a flashlight
and zinc-carbon batteries. First few nights, they're
fine. Then for the next few nights they're getting
dimmer. A few more nights of not bright enough but
better'n nothing. And on the last night still glowing
but just enough that if you hold it right against your
watch you can almost make out the time. Good memories

Anyway, because of the incredibly low internal impedance
of these nimh's, they dump all they've got until the
instant it's all gone. So it could well be that your
flashlight was indeed "full bright", but would have
been completely dead black in a matter of seconds,
or minutes.

The definitely do lose their charge quickly in
storage. Charge them just before you set off

Ken