a battery question

yuejian · Feb 8, 2002

Greetings,

I've got 2 sets of new Ni-MH batteries. As some discussion in this forum pointed out that new batteries don't last very long in D5/D7.

After my first set died in my D5, I used the batteries for my CANON flash. To my supprise, the "dead" batteries were able to charge the flash way over 100 times. I left them in the flash to fully discharge. Now, I wonder whether a fully discharge like this would actually help or hurt the batteries.

Any advice ? Thanks.

...Yuejian

morf · Feb 8, 2002

you will hear lost of noise on this one... check out bryans site

http://webpages.charter.net/bbiggers/DCExperiments/html/batteries_for_newbies.html

yuejian said:
Greetings,

I've got 2 sets of new Ni-MH batteries. As some discussion in this
forum pointed out that new batteries don't last very long in D5/D7.

After my first set died in my D5, I used the batteries for my CANON
flash. To my supprise, the "dead" batteries were able to charge the
flash way over 100 times. I left them in the flash to fully
discharge. Now, I wonder whether a fully discharge like this would
actually help or hurt the batteries.

Any advice ? Thanks.

...Yuejian

Mike Roberts · Feb 8, 2002

yuejian said:
After my first set died in my D5, I used the batteries for my CANON
flash. To my supprise, the "dead" batteries were able to charge the
flash way over 100 times. I left them in the flash to fully
discharge. Now, I wonder whether a fully discharge like this would
actually help or hurt the batteries.

New NiMH batteries need to be fully charged and fully discharged 3-4 times to condition them. If your charger has a conditioning cycle (good ones do) just run them through that 3-4 times. Otherwise, charge them (best on a slow charger for this) and discharge them with say your flash. I would then put them in flashlight until it will not light. Repeat 3-4 times. Then your batteries will be operating at peak efficiency.

Every so often (I do it every other month) repeat the entire process.

Buy new batteries once a year.

Mike Roberts

yuejian · Feb 8, 2002

After reading the link Morf pointed out, I thought I was clear. After reading yours, Mike, I'm confused again.

Thanks, guys.

...Yuejian

Mike Roberts said:
yuejian said:

After my first set died in my D5, I used the batteries for my CANON
flash. To my supprise, the "dead" batteries were able to charge the
flash way over 100 times. I left them in the flash to fully
discharge. Now, I wonder whether a fully discharge like this would
actually help or hurt the batteries.

Click to expand...

New NiMH batteries need to be fully charged and fully discharged
3-4 times to condition them. If your charger has a conditioning
cycle (good ones do) just run them through that 3-4 times.
Otherwise, charge them (best on a slow charger for this) and
discharge them with say your flash. I would then put them in
flashlight until it will not light. Repeat 3-4 times. Then your
batteries will be operating at peak efficiency.

Every so often (I do it every other month) repeat the entire process.

Buy new batteries once a year.

Mike Roberts

Mike Roberts · Feb 8, 2002

yuejian said:
After reading the link Morf pointed out, I thought I was clear.
After reading yours, Mike, I'm confused again.

Well I do not agree with everything the link says. I know I have been doing what I said (since my chargers have a conditioning cycle I have never done the flashlight discharge so maybe he is more right on that one) for 7 months now and have never had a problem with my batteries or their charge. Unless you want to count the time I dropped one in a rented Jeep, in the middle of nowhere, in the south-eastern desert of Utah, and it somehow warped space and time and has never been seen since. A 3 battery set of NiMh is pretty darn useless.

I get 150 or so pics per set of batteries using EVF for taking pics, LCD for review of 50% of the pics taken. I rarely use the flash.

I use AA Powerex 1700 mAh batteries and MaHa C204f chargers.

Mike Roberts

Paul vzo · Feb 8, 2002

My experience indicates that ALL battery types need a breaking in of 3-4 cycles, charge and discharge. I've found this true on Nicads, NiMh, and Lith-Ion, cell phone batteries, AA cells, whatever. Check out the superb new piece on the "Battery Shootout" on http://www.imaging-resource.com . (I hope I got the hyphen, lack of plurality right.) It's linked at http://www.dpreveiw 's home page. Be careful on the flashlight drill. When a rechargable goes below zero voltage, it can actually "flip" the polarity! Then it's NG! Discharge to dim, I would advise.

BTW, I've just experimented with the D7 "6V" input. It uses a 4.0 x 1.7mm style coax plug, Radio Shack #274-1532. I found out that it actually needs a minimum of 6.2 volts, less than that and the camera shuts off. I guess that's why http://www.thomas-distributing.com 's auxilary battery pack uses the 7.2 volt lithium model.

Mike Roberts said:
yuejian said:

After reading the link Morf pointed out, I thought I was clear.
After reading yours, Mike, I'm confused again.

Click to expand...

Well I do not agree with everything the link says. I know I have
been doing what I said (since my chargers have a conditioning cycle
I have never done the flashlight discharge so maybe he is more
right on that one) for 7 months now and have never had a problem
with my batteries or their charge. Unless you want to count the
time I dropped one in a rented Jeep, in the middle of nowhere, in
the south-eastern desert of Utah, and it somehow warped space and
time and has never been seen since. A 3 battery set of NiMh is
pretty darn useless.

I get 150 or so pics per set of batteries using EVF for taking
pics, LCD for review of 50% of the pics taken. I rarely use the
flash.

I use AA Powerex 1700 mAh batteries and MaHa C204f chargers.

Mike Roberts

Erik Wagenaar · Feb 9, 2002

Paul Verizzo said:
BTW, I've just experimented with the D7 "6V" input. It uses a 4.0
x 1.7mm style coax plug, Radio Shack #274-1532. I found out that
it actually needs a minimum of 6.2 volts, less than that and the
camera shuts off. I guess that's why http://www.thomas-distributing.com 's
auxilary battery pack uses the 7.2 volt lithium model.

I too did some experiments. My camera shuts down when voltage drops below 6.5 V. I will make myself a cable so I can use mz Sony Infolithium battery (7.2V) Erik

Vernon D Rainwater · Feb 9, 2002

Paul Verizzo said:
My experience indicates that ALL battery types need a breaking in
of 3-4 cycles, charge and discharge. I've found this true on
Nicads, NiMh, and Lith-Ion, cell phone batteries, AA cells,
whatever. Check out the superb new piece on the "Battery Shootout"
on http://www.imaging-resource.com . (I hope I got the hyphen, lack of
plurality right.) It's linked at http://www.dpreveiw 's home page. Be
careful on the flashlight drill. When a rechargable goes below
zero voltage, it can actually "flip" the polarity! Then it's NG!
Discharge to dim, I would advise.
BTW, I've just experimented with the D7 "6V" input. It uses a 4.0
x 1.7mm style coax plug, Radio Shack #274-1532. I found out that
it actually needs a minimum of 6.2 volts, less than that and the
camera shuts off. I guess that's why http://www.thomas-distributing.com 's
auxilary battery pack uses the 7.2 volt lithium model.

Hello Paul,

I have not fully decided on the D7 camera so still absorbing all the user comments that I can trying to learn and decide. Your description of the 6V input connector now has me wondering what size Coax Type plug is correct. Below is a link( in the Power Consumption - External Power section) that indicates the size is: Outer Barrel is 0.150 inches (3.81mm) and the Inner Contact is 0.050 inches and that it is referred to as a 3.8mm connector.
Can someone please post which is correct OR what is the correct size.
My Regards, Vernon

http://home-4.worldonline.nl/~t800373/

Paul vzo said:
Mike Roberts said:

yuejian said:

After reading the link Morf pointed out, I thought I was clear.
After reading yours, Mike, I'm confused again.

Click to expand...

Well I do not agree with everything the link says. I know I have
been doing what I said (since my chargers have a conditioning cycle
I have never done the flashlight discharge so maybe he is more
right on that one) for 7 months now and have never had a problem
with my batteries or their charge. Unless you want to count the
time I dropped one in a rented Jeep, in the middle of nowhere, in
the south-eastern desert of Utah, and it somehow warped space and
time and has never been seen since. A 3 battery set of NiMh is
pretty darn useless.

I get 150 or so pics per set of batteries using EVF for taking
pics, LCD for review of 50% of the pics taken. I rarely use the
flash.

I use AA Powerex 1700 mAh batteries and MaHa C204f chargers.

Mike Roberts

Click to expand...

yuejian · Feb 9, 2002

Paul Verizzo said:
My experience indicates that ALL battery types need a breaking in
of 3-4 cycles, charge and discharge. I've found this true on
Nicads, NiMh, and Lith-Ion, cell phone batteries, AA cells,
whatever. Check out the superb new piece on the "Battery Shootout"
on http://www.imaging-resource.com . (I hope I got the hyphen, lack of
plurality right.) It's linked at http://www.dpreveiw 's home page. Be
careful on the flashlight drill. When a rechargable goes below
zero voltage, it can actually "flip" the polarity! Then it's NG!
Discharge to dim, I would advise.

Thanks for the advices

Paul vzo said:
BTW, I've just experimented with the D7 "6V" input. It uses a 4.0
x 1.7mm style coax plug, Radio Shack #274-1532. I found out that
it actually needs a minimum of 6.2 volts, less than that and the
camera shuts off. I guess that's why http://www.thomas-distributing.com 's
auxilary battery pack uses the 7.2 volt lithium model.

Your 6.2v measurement must be with load. I use 4 Kodak NiMh of 1700mAh (who knows who makes them). When fully charged, each gives me 1.38v without load. The set would thus provide a total of 5.52v. They work fine. Compared to your 6.2v measurement, I don't know what would be responisble for the difference.

When the batteries are used up in my D5, the voltage drops down to around 1.28 v each, thus a total of 5.12v.

... Yuejian

David S Levin · Feb 9, 2002

yuejian said:
Your 6.2v measurement must be with load. I use 4 Kodak NiMh of
1700mAh (who knows who makes them). When fully charged, each gives
me 1.38v without load. The set would thus provide a total of 5.52v.
They work fine. Compared to your 6.2v measurement, I don't know
what would be responisble for the difference.

The 6v Port and battery compartment do not necessarily drive the same components. The battery compartment probably feeds a charge pump circuit to INCREASE the voltage to that required by the camera (ever wonder how a portable MP3 player can write to a 3v flash card with 1 battery).

What's the voltage on the Minolta AC adapter?

David S Levin · Feb 9, 2002

Mike Roberts said:
New NiMH batteries need to be fully charged and fully discharged
3-4 times to condition them. If your charger has a conditioning
cycle (good ones do) just run them through that 3-4 times.
Otherwise, charge them (best on a slow charger for this) and
discharge them with say your flash. I would then put them in
flashlight until it will not light. Repeat 3-4 times. Then your
batteries will be operating at peak efficiency.

According to thomas-distributing (or was it one of the other recent battery reviews) you should NEVER use an NiMh in a flashlight or other analog device. Problem is as the first battery reaches 0 volts it will see a reverse voltage from the other battery. Reverse voltage can damage an NiMh.

The Maha charger is designed to stop the discharge when the voltage reaches a certain level.

I suppse if it's a 1 cell flashlight there is no way to reverse bias.

Paul vzo · Feb 9, 2002

Erik, my Sony camcorder Info-Lithium batteries, nominally 7.2V, measure 8.35V after charging! I'm not yet brave enough to put that on my new D7. My other concern is that inside the batteries (I've taken old ones apart), besides the cylindrical LI cells, there is a tiny PC board that, I presume, is the "Info" function. It might also be part of the charger control. I bring this up because the battery needs to supply just over 1A with the LCD on, more than that when you shoot and record.

So far, none of my NiMh AA's last more than ten or fifteen minutes. Granted, they are almost two years old, but in my Oly they last forever. I've some new Ray0vacs, and they aren't doing any better. Granted, I haven't had but one charge-discharge cycle on them yet. Maybe they will get better.

I'm wondering if some of this battery consumption problem isn't early shutoff in the camera's firmware (I have the latest 121). When my camera shutoff due to low batteries, I took them out immediately and tested them, they measured 1.2V no load, and 1.1V with light load, whatever it is that my meter puts on it.

Paul

Erik Wagenaar said:
Paul Verizzo said:

BTW, I've just experimented with the D7 "6V" input. It uses a 4.0
x 1.7mm style coax plug, Radio Shack #274-1532. I found out that
it actually needs a minimum of 6.2 volts, less than that and the
camera shuts off. I guess that's why http://www.thomas-distributing.com 's
auxilary battery pack uses the 7.2 volt lithium model.

Click to expand...

I too did some experiments. My camera shuts down when voltage drops
below 6.5 V. I will make myself a cable so I can use mz Sony
Infolithium battery (7.2V) Erik

Paul vzo · Feb 9, 2002

Vernon, the differences you write of are too small to matter. The aforemention Radio Shack plug seems to work fine, and I would prefer the outer diameter on the large side of things so that it fits better, anyway.

Paul

Vernon D Rainwater said:
http://home-4.worldonline.nl/~t800373/

Vernon D Rainwater said:

Mike Roberts said:

yuejian said:

After reading the link Morf pointed out, I thought I was clear.
After reading yours, Mike, I'm confused again.

Click to expand...

Well I do not agree with everything the link says. I know I have
been doing what I said (since my chargers have a conditioning cycle
I have never done the flashlight discharge so maybe he is more
right on that one) for 7 months now and have never had a problem
with my batteries or their charge. Unless you want to count the
time I dropped one in a rented Jeep, in the middle of nowhere, in
the south-eastern desert of Utah, and it somehow warped space and
time and has never been seen since. A 3 battery set of NiMh is
pretty darn useless.

I get 150 or so pics per set of batteries using EVF for taking
pics, LCD for review of 50% of the pics taken. I rarely use the
flash.

I use AA Powerex 1700 mAh batteries and MaHa C204f chargers.

Mike Roberts

Click to expand...

Click to expand...

Paul vzo · Feb 9, 2002

Y, I presume you are refering to using the NiMh's in the battery compartment. Am I wrong? Do you have them plugged into the so-called "6V" input jack?

Be careful about those voltage measurements without load! A battery can have a high no-load voltage, but if the internal resistance is high due to characteristics or age, the load voltage will be much lower.

Paul

yuejian said:
Your 6.2v measurement must be with load. I use 4 Kodak NiMh of
1700mAh (who knows who makes them). When fully charged, each gives
me 1.38v without load. The set would thus provide a total of 5.52v.
They work fine. Compared to your 6.2v measurement, I don't know
what would be responisble for the difference.

When the batteries are used up in my D5, the voltage drops down to
around 1.28 v each, thus a total of 5.12v.

... Yuejian

yuejian · Feb 10, 2002

Paul, The earlier measured 6.2 volt (by another author) was with load I assume. The author pointed out that anything lower would cause the camera to shut off. I've heard the 6.2v number several times. It must be true.

In my measurement, however, the batteries was measured without load. With no load, the batteries give out only 5.52v. Under the camera's loading, the actual voltage of the batteries must be lower by whatever amount. Yet the camera works fine with lower than 5.52v.

So, how could the camera works fine with lower than 5.2v by batteries yet refuses to work when powered by an adapter with lower than 6.2v ?

Regards,

Yuejian

Paul Verizzo said:
Be careful about those voltage measurements without load! A
battery can have a high no-load voltage, but if the internal
resistance is high due to characteristics or age, the load voltage
will be much lower.

Paul

yuejian said:

Your 6.2v measurement must be with load. I use 4 Kodak NiMh of
1700mAh (who knows who makes them). When fully charged, each gives
me 1.38v without load. The set would thus provide a total of 5.52v.
They work fine. Compared to your 6.2v measurement, I don't know
what would be responisble for the difference.

When the batteries are used up in my D5, the voltage drops down to
around 1.28 v each, thus a total of 5.12v.

... Yuejian

Click to expand...

yuejian · Feb 10, 2002

Thanks, David. Driving different components could be a reason.

...Yuejian

David S Levin said:
yuejian said:

Your 6.2v measurement must be with load. I use 4 Kodak NiMh of
1700mAh (who knows who makes them). When fully charged, each gives
me 1.38v without load. The set would thus provide a total of 5.52v.
They work fine. Compared to your 6.2v measurement, I don't know
what would be responisble for the difference.

Click to expand...

The 6v Port and battery compartment do not necessarily drive the
same components. The battery compartment probably feeds a charge
pump circuit to INCREASE the voltage to that required by the camera
(ever wonder how a portable MP3 player can write to a 3v flash card
with 1 battery).

What's the voltage on the Minolta AC adapter?

Tom Brock · Feb 10, 2002

yuejian said:
...Yuejian

David S Levin said:

yuejian said:

Your 6.2v measurement must be with load. I use 4 Kodak NiMh of
1700mAh (who knows who makes them). When fully charged, each gives
me 1.38v without load. The set would thus provide a total of 5.52v.
They work fine. Compared to your 6.2v measurement, I don't know
what would be responisble for the difference.

Click to expand...

The 6v Port and battery compartment do not necessarily drive the
same components. The battery compartment probably feeds a charge
pump circuit to INCREASE the voltage to that required by the camera
(ever wonder how a portable MP3 player can write to a 3v flash card
with 1 battery).

What's the voltage on the Minolta AC adapter?

Click to expand...

Tom Brock · Feb 10, 2002

This camera seems to be designed for a nominal voltage of 4-1.55V cells and may be pushing the lower limit of its power spec with 4-1.2V NiMH cells at full charge (1.38V). That could be why the heating if the cells aren't fully charged, why the power remaining indicator dies immediately with almost no warning, and why some cameras just seem to stop working and hum. Just a thought based on everything I have read about this camera and the issues associated with powering it. I would really like to know the input voltage spec on the camera circuits. I'll bet 5 NiMH batteries would work like a charm and you would be able to use almost all of the charge in them unlike what we are able to do with 4 NiMH batteries. Of couse since 5 won't fit in the camera, this would have to be done as an external power source that plugs in to the camera's external power socket.

yuejian said:
...Yuejian

David S Levin said:

yuejian said:

Your 6.2v measurement must be with load. I use 4 Kodak NiMh of
1700mAh (who knows who makes them). When fully charged, each gives
me 1.38v without load. The set would thus provide a total of 5.52v.
They work fine. Compared to your 6.2v measurement, I don't know
what would be responisble for the difference.

Click to expand...

The 6v Port and battery compartment do not necessarily drive the
same components. The battery compartment probably feeds a charge
pump circuit to INCREASE the voltage to that required by the camera
(ever wonder how a portable MP3 player can write to a 3v flash card
with 1 battery).

What's the voltage on the Minolta AC adapter?

Click to expand...

Paul vzo · Feb 11, 2002

I could be wrong, but it sounds like we are talking internal vs. external batteries. The 6.2 figure is for external. Internal seems to shut down at 4V. That's a guesstimate based on the following: Nicads and NiMh are considered dead when the voltage drops to 1 V per cell, I forget how much load that is rated at, but it definitely is under load. If I run the camera until it dies and immediately remove the batteries, and immediately test with my digital VOM in its "Battery Test" mode, I get about 1.09V. While you are right in that being above 1V, the VOM does not put a heavy load on the battery; it's more designed for alkaline and standard batteries. Unfortunately, I don't know where my instruction book is to find out what the load is. Maybe someday I'll run a couple of skinny wires to the battery slots and test directly.

yuejian said:
In my measurement, however, the batteries was measured without
load. With no load, the batteries give out only 5.52v. Under the
camera's loading, the actual voltage of the batteries must be lower
by whatever amount. Yet the camera works fine with lower than 5.52v.

So, how could the camera works fine with lower than 5.2v by
batteries yet refuses to work when powered by an adapter with lower
than 6.2v ?

Regards,

Yuejian

Paul Verizzo said:

Be careful about those voltage measurements without load! A
battery can have a high no-load voltage, but if the internal
resistance is high due to characteristics or age, the load voltage
will be much lower.

Paul

yuejian said:

Your 6.2v measurement must be with load. I use 4 Kodak NiMh of
1700mAh (who knows who makes them). When fully charged, each gives
me 1.38v without load. The set would thus provide a total of 5.52v.
They work fine. Compared to your 6.2v measurement, I don't know
what would be responisble for the difference.

When the batteries are used up in my D5, the voltage drops down to
around 1.28 v each, thus a total of 5.12v.

... Yuejian

Click to expand...

Click to expand...

JIM NODLER · Feb 11, 2002

Just some thoughts about the difference in battery voltage on the internal cells and an external power source. It could be that a voltage increasing circuit is used to bring the internal voltage up, but I think it more likely that a circuit is used to bring the external power supply voltage down to the optimum internal operating voltage which would probable be slightly less than 6 volts. Thre reason the exernal supply needs at least 6.2 or 6.5 volts depending on who you believe is that a voltage regulator cannot work if there is not a differential between the input voltage and the output voltage. It would be nice if the camera manufactures would share specifications on things such as internal battery minimum/maximum voltages and amperage, and the same thing for the external power input.

The reason they do not could be attributed to fear of loosing out on selling a $50 ac adaptor when we can buy the same item for $9.95 at RS if we know the paramaters or fear that someone will believe that a cheap "6v" adaptor actually puts out 6v instead of more than 10 on occasion. This could be enough to burn the power circuit out. Overvolting the input will certainly take out the power supply on a dell laptop [expensive lesson] when you would assume the manufacturer would take some variance into account [expensive lesson]. Or it could be that that might take a few more dollars to publish and they don't think anyone is interested or can understand specifications anyway.

If anyone has one of the minolta ac adaptors, it would probably be helpful to measure the open circuit voltage and assume that is the safe maximum for power input off of a third party supply.

David S Levin said:
Mike Roberts said:

New NiMH batteries need to be fully charged and fully discharged
3-4 times to condition them. If your charger has a conditioning
cycle (good ones do) just run them through that 3-4 times.
Otherwise, charge them (best on a slow charger for this) and
discharge them with say your flash. I would then put them in
flashlight until it will not light. Repeat 3-4 times. Then your
batteries will be operating at peak efficiency.

Click to expand...

According to thomas-distributing (or was it one of the other recent
battery reviews) you should NEVER use an NiMh in a flashlight or
other analog device. Problem is as the first battery reaches 0
volts it will see a reverse voltage from the other battery.
Reverse voltage can damage an NiMh.

The Maha charger is designed to stop the discharge when the voltage
reaches a certain level.

I suppse if it's a 1 cell flashlight there is no way to reverse bias.

--flashman

a battery question

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