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Batteries and rechargers

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Anonymous
December 26, 2004 12:07:20 AM

Archived from groups: rec.photo.digital (More info?)

Did a search in Google-groups for batteries and rechargers, and it
looks like rec.photo.digital is the place to go for discussions.

Read the Maha MHC401FS is the latest and the greatest recharger and
got it with 4 GP 2000 batteries as a package deal. Charged the
batteries up and put them in the camera and went to a party and was
well satisfied.

On the second slow recharge, three of the batteries topped off at 1
hour, but the 4th is still charging after 2 hours. Did I get a bad
battery?

Thanks

Mike

More about : batteries rechargers

Anonymous
December 26, 2004 1:00:28 AM

Archived from groups: rec.photo.digital (More info?)

"Mike Fox" <mikefox@satx.rr.com> wrote in message
news:44lrs01innnisqc3svqe5v9qrsplrrdc6a@4ax.com...
> Did a search in Google-groups for batteries and rechargers, and it
> looks like rec.photo.digital is the place to go for discussions.
>
> Read the Maha MHC401FS is the latest and the greatest recharger and
> got it with 4 GP 2000 batteries as a package deal. Charged the
> batteries up and put them in the camera and went to a party and was
> well satisfied.
>
> On the second slow recharge, three of the batteries topped off at 1
> hour, but the 4th is still charging after 2 hours. Did I get a bad
> battery?
>
> Thanks
>
> Mike

Always treat the batteries as a set. In your case I would just use and see
how the set performs in the camera. You may find after a number of
charge/discharge cycles the problem either goes away or doesn't seriously
impair performance. Good news is you can get four Duracell's in compusa for
$10, so it's not worth worrying about too much .
Dave Cohen
Anonymous
December 26, 2004 8:50:12 AM

Archived from groups: rec.photo.digital (More info?)

Mike Fox wrote:
> Did a search in Google-groups for batteries and rechargers, and it
> looks like rec.photo.digital is the place to go for discussions.
>
> Read the Maha MHC401FS is the latest and the greatest recharger and
> got it with 4 GP 2000 batteries as a package deal. Charged the
> batteries up and put them in the camera and went to a party and was
> well satisfied.
>
> On the second slow recharge, three of the batteries topped off at 1
> hour, but the 4th is still charging after 2 hours. Did I get a bad
> battery?
>
> Thanks
>
> Mike
I would cycle the batteries 3 or 4 times before I worried about it too
much, I have had that happen with a couple of sets when they were new.

Don
Related resources
Anonymous
December 26, 2004 6:56:51 PM

Archived from groups: rec.photo.digital (More info?)

"Mike Fox" <mikefox@satx.rr.com> wrote in message
news:44lrs01innnisqc3svqe5v9qrsplrrdc6a@4ax.com...
> Did a search in Google-groups for batteries and rechargers, and it
> looks like rec.photo.digital is the place to go for discussions.
>
> Read the Maha MHC401FS is the latest and the greatest recharger and
> got it with 4 GP 2000 batteries as a package deal. Charged the
> batteries up and put them in the camera and went to a party and was
> well satisfied.
>
> On the second slow recharge, three of the batteries topped off at 1
> hour, but the 4th is still charging after 2 hours. Did I get a bad
> battery?
>
> Thanks
>
> Mike

Some new sets of batteries all come up to full charge almost simultaneously,
but I have often seen one or two batteries in a new set take much longer to
charge, at least the first time or so. Sometimes they do the same later in
life too. When this happens with my Maha MH-C401FS on slow I usually just
switch it to fast to teach the stubborn ones to behave. Works for me. ;-)

N.
Anonymous
December 26, 2004 6:56:52 PM

Archived from groups: rec.photo.digital (More info?)

"Nostrobino" <not.here@ultranet.com> wrote in message
news:7bBzd.6040$by5.2666@newssvr19.news.prodigy.com...
>
>
> Some new sets of batteries all come up to full charge almost
> simultaneously, but I have often seen one or two batteries in a new set
> take much longer to charge, at least the first time or so. Sometimes they
> do the same later in life too. When this happens with my Maha MH-C401FS on
> slow I usually just switch it to fast to teach the stubborn ones to
> behave. Works for me. ;-)
>
> N.
>

That is called equalization. Measure the open circuit voltage of a set of
batteries, try to match up the ones that will charge together. For example,
one of my chargers will do 2 sets of two cells. I measure the OC voltage of
4 cells, the 2 lowest go in one compartment, the other 2 go together in the
other compartment. Hopefully, as they discharge as a set, the voltage will
be the same on all of them. One hot cell or a poor cell in a set can screw
things up.

This is nothing new. The principle has been around for ages, especially in
large battery installations.
Anonymous
December 27, 2004 1:33:01 AM

Archived from groups: rec.photo.digital (More info?)

"Justín Käse" <chupacabra@operamail.com> wrote in message
news:41cf33ab.2840136@chupacabra...
> In Message-ID:<10stpl43ceb0m64@corp.supernews.com> posted on Sun, 26 Dec
> 2004 11:28:18 -0500, Rudy Benner wrote:
>
> >That is called equalization. Measure the open circuit voltage of a set of
> >batteries, try to match up the ones that will charge together. For
example,
> >one of my chargers will do 2 sets of two cells. I measure the OC voltage
of
> >4 cells, the 2 lowest go in one compartment, the other 2 go together in
the
> >other compartment. Hopefully, as they discharge as a set, the voltage
will
> >be the same on all of them. One hot cell or a poor cell in a set can
screw
> >things up.
>
> Modern "smart" chargers treat each cell according to its needs,
> so you don't have to pair up anything.
> --
>
> JK

Depends on which chargers you are working with. Some such
as the Maha 204F charge 2 pairs of cells so the cells should be
matched (yes, I know it is an older charger, but is still around
quite a bit). The newer Maha 401 charges 4 individual cells
so each is charged according to it's needs. That said, I do watch
mine to make sure they all hit full charge about the same time.
I do notice more of a difference if they have sat for a month or
longer - the self discharge is not matched for the cells - but if
I run them down in the camera then recharge, they all come up
about the same time.
December 27, 2004 1:33:02 AM

Archived from groups: rec.photo.digital (More info?)

Mike F wrote:

> "Justín Käse" <chupacabra@operamail.com> wrote in message
> news:41cf33ab.2840136@chupacabra...
>
>>In Message-ID:<10stpl43ceb0m64@corp.supernews.com> posted on Sun, 26 Dec
>>2004 11:28:18 -0500, Rudy Benner wrote:
>>
>>
>>>That is called equalization. Measure the open circuit voltage of a set of
>>>batteries, try to match up the ones that will charge together. For
>
> example,
>
>>>one of my chargers will do 2 sets of two cells. I measure the OC voltage
>
> of
>
>>>4 cells, the 2 lowest go in one compartment, the other 2 go together in
>
> the
>
>>>other compartment. Hopefully, as they discharge as a set, the voltage
>
> will
>
>>>be the same on all of them. One hot cell or a poor cell in a set can
>
> screw
>
>>>things up.
>>
>>Modern "smart" chargers treat each cell according to its needs,
>>so you don't have to pair up anything.
>>--
>>
>>JK
>
>
> Depends on which chargers you are working with. Some such
> as the Maha 204F charge 2 pairs of cells so the cells should be
> matched (yes, I know it is an older charger, but is still around
> quite a bit). The newer Maha 401 charges 4 individual cells
> so each is charged according to it's needs. That said, I do watch
> mine to make sure they all hit full charge about the same time.
> I do notice more of a difference if they have sat for a month or
> longer - the self discharge is not matched for the cells - but if
> I run them down in the camera then recharge, they all come up
> about the same time.
>
>


This observation seems to imply that multiple cells working together
seem to discharge at an equitable rate, but left to wander about
separately in a spare pocket, they self-discharge somewhat differently.
Interesting, I hadn't thought of it that way.

--
jer
email reply - I am not a 'ten'
Anonymous
December 27, 2004 1:33:03 AM

Archived from groups: rec.photo.digital (More info?)

"Jer" <gdunn@airmail.ten> wrote in message
news:cqnibv$qvj@library2.airnews.net...
> Mike F wrote:
>
>> "Justín Käse" <chupacabra@operamail.com> wrote in message
>> news:41cf33ab.2840136@chupacabra...
>>
>>>In Message-ID:<10stpl43ceb0m64@corp.supernews.com> posted on Sun, 26 Dec
>>>2004 11:28:18 -0500, Rudy Benner wrote:
>>>
>>>
>>>>That is called equalization. Measure the open circuit voltage of a set
>>>>of
>>>>batteries, try to match up the ones that will charge together. For
>>
>> example,
>>
>>>>one of my chargers will do 2 sets of two cells. I measure the OC voltage
>>
>> of
>>
>>>>4 cells, the 2 lowest go in one compartment, the other 2 go together in
>>
>> the
>>
>>>>other compartment. Hopefully, as they discharge as a set, the voltage
>>
>> will
>>
>>>>be the same on all of them. One hot cell or a poor cell in a set can
>>
>> screw
>>
>>>>things up.
>>>
>>>Modern "smart" chargers treat each cell according to its needs,
>>>so you don't have to pair up anything.
>>>--
>>>
>>>JK
>>
>>
>> Depends on which chargers you are working with. Some such
>> as the Maha 204F charge 2 pairs of cells so the cells should be
>> matched (yes, I know it is an older charger, but is still around
>> quite a bit). The newer Maha 401 charges 4 individual cells
>> so each is charged according to it's needs. That said, I do watch
>> mine to make sure they all hit full charge about the same time.
>> I do notice more of a difference if they have sat for a month or
>> longer - the self discharge is not matched for the cells - but if
>> I run them down in the camera then recharge, they all come up
>> about the same time.
>>
>>
>
>
> This observation seems to imply that multiple cells working together seem
> to discharge at an equitable rate, but left to wander about separately in
> a spare pocket, they self-discharge somewhat differently. Interesting, I
> hadn't thought of it that way.
>
> --
> jer
> email reply - I am not a 'ten'

When connected in the device, they are in series, the discharge current will
be equal for all cells. Hopefully, they all start at the same voltage and
have the same discharge characteristics. The same principles apply to
industrial installations, with which I am quite familiar.

When I buy batteries, I keep them as a set. The same batteries are always
used together as a set. They are charged together as a set. I do try to pair
them according to OC voltage because my chargers happen to be setup for 2
cells in series in each compartment.

R.
Anonymous
December 27, 2004 6:17:33 AM

Archived from groups: rec.photo.digital (More info?)

"Jer" <gdunn@airmail.ten> wrote in message
news:cqnibv$qvj@library2.airnews.net...
>
> This observation seems to imply that multiple cells working together
> seem to discharge at an equitable rate, but left to wander about
> separately in a spare pocket, they self-discharge somewhat differently.
> Interesting, I hadn't thought of it that way.
>
> --
> jer
> email reply - I am not a 'ten'

I do keep my batteries together in sets of 4 and have seen this
effect if they have been left for a month or so where the
leakage is a significant portion of the discharge. I have found
the nylon battery wallet like the one on this page
http://store.yahoo.com/greenbatteries-store/batteryhold...
to work real well for my batteries. I put a piece of 3 * 5 index
card inside with the batteries and write the last date they
were charged so I know approximately what their state
of charge is. One trick I found, after using the batteries, I
put them with the positive end down so I know they are
discharged (normally they are stored with the tip up).
NiMh sure beat the old NiCd though with their memory
(well, the new chargers help too).

mikey
Anonymous
December 27, 2004 7:17:43 AM

Archived from groups: rec.photo.digital (More info?)

Jer <gdunn@airmail.ten> writes:

>This observation seems to imply that multiple cells working together
>seem to discharge at an equitable rate, but left to wander about
>separately in a spare pocket, they self-discharge somewhat differently.
> Interesting, I hadn't thought of it that way.

It makes sense. When in a camera, GPS receiver, or just about any other
battery-powered device, one "set" of cell is connected in series by the
battery compartment wiring. When the device is used, exactly the same
number of amp-hours of capacity is withdrawn from each cell because all
devices in a series string see the same current. So, it takes exactly
the same number of amp-hours to bring all cells back to the state they
were in before you started using the device, and series charging works
well.

On the other hand, self-discharge happens within each cell at rates that
may vary from cell to cell.

This is one reason why NiCd and NiMH chargers switch to trickle charge
after they finish fast charging. Self-discharge may cause the cells in
the battery pack to be in different charge states. When the charger
stops fast charging, some cells may be at 100% charge while others are
at (say) 90%. Trickle charge brings the 90% cells up to 100%, without
harming the ones already at 100%.

Dave
Anonymous
December 27, 2004 7:42:27 AM

Archived from groups: rec.photo.digital (More info?)

Dave Martindale wrote:

<snip>

Hi Dave...

Not a photographer, an old retired electrical guy who takes
a *lot* of pictures :) 

> It makes sense. When in a camera, GPS receiver, or just about any other
> battery-powered device, one "set" of cell is connected in series by the
> battery compartment wiring. When the device is used, exactly the same
> number of amp-hours of capacity is withdrawn from each cell because all
> devices in a series string see the same current. So, it takes exactly
> the same number of amp-hours to bring all cells back to the state they
> were in before you started using the device, and series charging works
> well.

With all due respect, Dave, there's no reason to expect
all of the batts in a series circuit to deliver the same
amount of energy... in fact, it would be incredibly rare
were it to happen.

Nevertheless, you sort of ended up with the right answer,
even if for a different reason :) 

What does in fact happen (when the device is on) is that
the "stronger" cell or cells will somewhat charge the
weaker cell or cells. So, they do in fact end up closer
together when finally removed than they would have if
they were stored loose. Again, provided that the
device they're in is turned on once in a while.

Take care.

Ken
December 27, 2004 1:26:24 PM

Archived from groups: rec.photo.digital (More info?)

Ken Weitzel <kweitzel@shaw.ca> wrote in news:ToMzd.594476$nl.388721
@pd7tw3no:
>
> Dave Martindale wrote:
>
>> It makes sense. When in a camera, GPS receiver, or just about any other
>> battery-powered device, one "set" of cell is connected in series by the
>> battery compartment wiring. When the device is used, exactly the same
>> number of amp-hours of capacity is withdrawn from each cell because all
>> devices in a series string see the same current. So, it takes exactly
>> the same number of amp-hours to bring all cells back to the state they
>> were in before you started using the device, and series charging works
>> well.
>
> With all due respect, Dave, there's no reason to expect
> all of the batts in a series circuit to deliver the same
> amount of energy... in fact, it would be incredibly rare
> were it to happen.
>
> What does in fact happen (when the device is on) is that
> the "stronger" cell or cells will somewhat charge the
> weaker cell or cells. So, they do in fact end up closer
> together when finally removed than they would have if
> they were stored loose. Again, provided that the
> device they're in is turned on once in a while.

No, Dave is correct. You have described what would happen if the cells
were connected in parallel. Most devices work with the cells in serial,
which is where the same amps flow through all the cells, just as Dave
described.


--
Mark Heyes (New Zealand)
See my pics at www.gigatech.co.nz (last updated 12-Nov-04)
"There are 10 types of people, those that
understand binary and those that don't"
Anonymous
December 27, 2004 7:14:15 PM

Archived from groups: rec.photo.digital (More info?)

"MarkH" <markat@atdot.dot.dot> wrote in message
news:krRzd.1602031$SM5.129864@news.easynews.com...
> Ken Weitzel <kweitzel@shaw.ca> wrote in news:ToMzd.594476$nl.388721
> @pd7tw3no:
> >
> > Dave Martindale wrote:
> >
> >> It makes sense. When in a camera, GPS receiver, or just about any
other
> >> battery-powered device, one "set" of cell is connected in series by the
> >> battery compartment wiring. When the device is used, exactly the same
> >> number of amp-hours of capacity is withdrawn from each cell because all
> >> devices in a series string see the same current. So, it takes exactly
> >> the same number of amp-hours to bring all cells back to the state they
> >> were in before you started using the device, and series charging works
> >> well.
> >
> > With all due respect, Dave, there's no reason to expect
> > all of the batts in a series circuit to deliver the same
> > amount of energy... in fact, it would be incredibly rare
> > were it to happen.
> >
> > What does in fact happen (when the device is on) is that
> > the "stronger" cell or cells will somewhat charge the
> > weaker cell or cells. So, they do in fact end up closer
> > together when finally removed than they would have if
> > they were stored loose. Again, provided that the
> > device they're in is turned on once in a while.
>
> No, Dave is correct. You have described what would happen if the cells
> were connected in parallel. Most devices work with the cells in serial,
> which is where the same amps flow through all the cells, just as Dave
> described.
>

OK, to be technically correct, just so we have the same terms here,
in a series circuit, the current through any point in the circuit is the
same as anywhere else, HOWEVER, the power from each battery
may not be the same -- power is current * voltage -- if the two
(or more) batteries are in series but are at different voltages (not
a desirable state), then the power from the battery at 0.9 volts is
NOT the same as the power from the battery at 1.4 volts even if
the current is the same. That all said and done, that is usually not
a problem if your batteries are in halfway decent shape. If one is
bad though, you can get some interesting things happening (if one
is bad and the internal resistance has gone up, you will heat that
battery up AND find you can't run the camera or whatever).

This is typically what happens with the lead acid car batteries -
one cell gets enough sulphate sludge in the bottom to short the
cell and discharge it. A discharged cell has a high internal resistance
and you can't start the car because of the drop across the bad
cell more than because you are 2 volts low on the available
voltage. AND the cell will start to boil if you try to pull high
currents because it's internal resistance makes it have most of
the voltage drop across it. Lots of fancy battery testers out
there for car batteries - almost all of the failed ones I have
seen could be easily found with a hydrometer - 5 cells at a
normal charge state and the 6th almost pure water (totally
dead). Enough rambling. Later !!

mikey
Anonymous
December 27, 2004 8:51:32 PM

Archived from groups: rec.photo.digital (More info?)

MarkH wrote:
> Ken Weitzel <kweitzel@shaw.ca> wrote in news:ToMzd.594476$nl.388721
> @pd7tw3no:
>
>>Dave Martindale wrote:
>>
>>
>>>It makes sense. When in a camera, GPS receiver, or just about any other
>>>battery-powered device, one "set" of cell is connected in series by the
>>>battery compartment wiring. When the device is used, exactly the same
>>>number of amp-hours of capacity is withdrawn from each cell because all
>>>devices in a series string see the same current. So, it takes exactly
>>>the same number of amp-hours to bring all cells back to the state they
>>>were in before you started using the device, and series charging works
>>>well.
>>
>>With all due respect, Dave, there's no reason to expect
>>all of the batts in a series circuit to deliver the same
>>amount of energy... in fact, it would be incredibly rare
>>were it to happen.
>>
>>What does in fact happen (when the device is on) is that
>>the "stronger" cell or cells will somewhat charge the
>>weaker cell or cells. So, they do in fact end up closer
>>together when finally removed than they would have if
>>they were stored loose. Again, provided that the
>>device they're in is turned on once in a while.
>
>
> No, Dave is correct. You have described what would happen if the cells
> were connected in parallel. Most devices work with the cells in serial,
> which is where the same amps flow through all the cells, just as Dave
> described.

Hi Mark...

You're absolutely right; the same current flows through
each and every battery. The catch is that each individual
cell doesn't contribute the same amount of energy.

Ken
Anonymous
December 27, 2004 10:30:01 PM

Archived from groups: rec.photo.digital (More info?)

Ken Weitzel <kweitzel@shaw.ca> writes:

>> It makes sense. When in a camera, GPS receiver, or just about any other
>> battery-powered device, one "set" of cell is connected in series by the
>> battery compartment wiring. When the device is used, exactly the same
>> number of amp-hours of capacity is withdrawn from each cell because all
>> devices in a series string see the same current.

>With all due respect, Dave, there's no reason to expect
>all of the batts in a series circuit to deliver the same
>amount of energy... in fact, it would be incredibly rare
>were it to happen.

I didn't say that they delivered the same amount of energy. Energy is
measured in watt-hours or joules, and depends on both voltage and
current. So a cell with a slightly higher terminal voltage delivers
more energy than a lower-voltage cell.

What I said was that all cells delivered the same number of amp-hours.
Since the cells are connected in series, the current through them must
always be the same, so the amp-hours *must* be the same for each cell.
The only exception would be devices that have a tap somewhere in the
battery string to obtain a lower voltage.

>Nevertheless, you sort of ended up with the right answer,
>even if for a different reason :) 

Equal energy and equal amp-hours are not the same thing.

>What does in fact happen (when the device is on) is that
>the "stronger" cell or cells will somewhat charge the
>weaker cell or cells. So, they do in fact end up closer
>together when finally removed than they would have if
>they were stored loose. Again, provided that the
>device they're in is turned on once in a while.

That's not true at all in a series string. Unless some cells have
become so discharged that they go into reverse charge, *all* cells
discharge the same amount at the same time. Stronger cells will provide
more of the energy because their voltage is slightly higher, that's all.
The only time strong cells charge weak ones is if the weak one drops to
zero volts and begins *reverse* charging, which will quickly destroy the
cell.

Now, if the cells were connected in parallel, you would see some of
the "charge balancing" you suggest. But I don't think I've ever seen a
battery-powered device with the cells connected in parallel.

Dave
Anonymous
December 27, 2004 10:33:02 PM

Archived from groups: rec.photo.digital (More info?)

"Mike F" <spam_me_not_mr.gadget2@comcast.net> writes:

>OK, to be technically correct, just so we have the same terms here,
>in a series circuit, the current through any point in the circuit is the
>same as anywhere else, HOWEVER, the power from each battery
>may not be the same -- power is current * voltage -- if the two
>(or more) batteries are in series but are at different voltages (not
>a desirable state), then the power from the battery at 0.9 volts is
>NOT the same as the power from the battery at 1.4 volts even if
>the current is the same.

That's why I said that each cell delivered the same number of amp-hours
of capacity, not that they delivered the same energy. Even if the cell
voltages differ slightly, the amp-hours discharged remain equal, and the
number of amp-hours required to recharge the cells is also the same
(except for any differences in the charge efficiency of the cells).

Dave
Anonymous
December 27, 2004 11:38:41 PM

Archived from groups: rec.photo.digital (More info?)

"Dave Martindale" <davem@cs.ubc.ca> wrote in message
news:cqpo1e$rj$2@mughi.cs.ubc.ca...
> "Mike F" <spam_me_not_mr.gadget2@comcast.net> writes:
>
> >OK, to be technically correct, just so we have the same terms here,
> >in a series circuit, the current through any point in the circuit is the
> >same as anywhere else, HOWEVER, the power from each battery
> >may not be the same -- power is current * voltage -- if the two
> >(or more) batteries are in series but are at different voltages (not
> >a desirable state), then the power from the battery at 0.9 volts is
> >NOT the same as the power from the battery at 1.4 volts even if
> >the current is the same.
>
> That's why I said that each cell delivered the same number of amp-hours
> of capacity, not that they delivered the same energy. Even if the cell
> voltages differ slightly, the amp-hours discharged remain equal, and the
> number of amp-hours required to recharge the cells is also the same
> (except for any differences in the charge efficiency of the cells).
>
> Dave

I agree with you Dave, just wanted to make sure some of the terms
were clear since it is easy for people to equate amphours and power
not understanding there is a difference. The ideal model of a battery is
a voltage source -- in real life, that voltage source has a resistor across
it that is internal to the battery and gives you the self-discharge effect.
While it is true that the same number of amp-hours are required to
recharge cells, the time may not be the same since most smart chargers
change the charge current based on the voltage across the cell so it
may appear the number of amp hours put back are different because
the charge time is different. Hopefully, your batteries will all behave
about the same and peace and harmony will result ... but, this is the
real world ! ;-)

mikey
!