In article ,
Capt. Neal® wrote:

You haven't read the post where I clarified your above misconception by
explaining lead/acid batteries don't store electrons per se but use
electrons provided in the charging process to drive chemical reactions
that change the composition of the plates and set them up for chemical
reactions in the other direction that changes the composition of the
plates back with an attendant release of electrons via the chemical
reactions. One could say electrons are stored vicariously.

CN

Ahhh, but that is not what you posted....
and that is a very simplistic view of the actual Chemistry, and Physics
involved here...and it also doesn't go to the OP's orginal question, and
your claim that wet cell batteries individual cell charge state will
self-level between cells connected in series by discharging under load.
This is ONLY true when the cells are COMPLETELY discharged, and they are
DEAD FLAT. At that point they are all equal, and not before.



Bruce in alaska
--
add a 2 before @

In article ,
Capt. Neal® wrote:

Not what I said. I said a battery is a tank that uses chemical reactions
to store or release electrons.

No that is NOT what you posted.... Hmmm Backtracking a bit here are we?

In actual fact, H2SO4 is a conductor of electricity. You dispute this?
Try putting the stripped ends of an extension cord that is plugged into
a wall outlet into a beaker of H2SO4 and see the sparks fly.......
If it wasn't a conductor of electricity it would not blow the circuit
breaker, when doing the above experiment.

In actual fact, Lead is also a conductor of electricity, and PB02
is also a conductor of electricity. You dispute this? Try the same
experiment above with a chunk of lead or Lead Ozide. Same result the
breaker blows.

Now tell us all that there is "NO Conduction of Electrons" thru
a beaker of H2SO4, (a conductor) that has, a chunk of lead, (another
conductor) and a chunk of Lead Ozide, (another conductor) in it. when a
the two chunks are connected to the stripped ends of the wires, as in
the above experiment. The breaker certainly trips. If there is no
conduction in a battery, why does the breaker trip? Inquiring minds
would certainly like to know.

The rest of us know, that the above Grammer School Physics Experiment
demonstrates, that all the above conductors when placed in series do
consist of an electrical circuit, and that electrons do flow thru the
above circuit very well. Now that we have explained it to you, in terms
that you certainly can verify, by doing the above experiment, you should
be nice and go away. If not, then as I stated before, infusing the
required knowlege is beyound your capability, due to "High Internal
Resistance" between your ears.


Bruce in alaska I hate teaching Grammer School Physics, and
thought that when I retired i wouldn't be
doing it anymore....... Oh well.....
--
add a 2 before @

In article ,
Capt. Neal® wrote:

Semantics and an honest mistake explained in the post above. Here is a cut
and paste for your edification.

***************

Thanks for pointing out that inconsistency. My bad.

Semantics again, but you are correct. I should have said some of the
electrons
flowing through the circuit (external) will drive the chemical reaction in
the
discharged battery so it's state of charge will be increased.

Even though the positive and negative poles are on opposite ends of an AA
cell, electricity does not really flow through from end to end as there is
no internal circuit as such - just chemical reactions as in a lead/acid
battery.

But let's not miss the point by pointing out semantics discrepancies. The
fact
is the discharged cell will take on some charge from the circuit. The same
goes for two 12v lead/acid batteries in a circuit.

CN


Now there is a BACKTRACK, if i have ever seen one......


Me

In article ,
Capt. Neal® wrote:


Thanks for pointing out that inconsistency. My bad.

Semantics again, but you are correct. I should have said some of the
electrons
flowing through the circuit (external) will drive the chemical reaction in
the
discharged battery so it's state of charge will be increased.

Even though the positive and negative poles are on opposite ends of an AA
cell, electricity does not really flow through from end to end as there is
no internal circuit as such - just chemical reactions as in a lead/acid
battery.

But let's not miss the point by pointing out semantics discrepancies. The
fact
is the discharged cell will take on some charge from the circuit. The same
goes for two 12v lead/acid batteries in a circuit.

CN


Oh, Oh, what's this, another BACKTRACK..... Hmmmm, maybe the
Internal Resistance, is falling....... NOT.......


Me

In article ,
Capt. Neal® wrote:

Negative sarge! A charged battery has used electrons provided for it in
the charging process to change the chemical composition of the plates
so these same plates can again change their composition through chemical
reactions during the discharge cycle to provide electrons. Electrons aren't
rally stored as they are in a capacitor. Potential to release electrons is
stored by chemical reactions that change the plate metal composition.

CN

but that is not what you posted.... Hmmm, another BACKTRACK.....

Are you getting tired of doing that???? Could it be your theories
are wrong??? Maybe you just don't comprehend the system???


Me who wonders......

Oomph is as a good as any other term

Practical electricity is about energy, charge and time.

Volts, amps, ohms are just derivations from energy, charge and time.

Until someone actually meets a volt, shakes a hand with an amp or goes out
to dine with the parents of an ohm I'll maintain my heritical views.

Oomph is now the unit of doing something, I patent it and claim copyright.
Volts and Amps are just illegitamate children. Ohms are the result of incest
on a dark night, useful and I'll keep them working out of sight in the
skullery.

Please do not confuse terminolgy and education with reality.

Only 9 angels dance on the top of the pinhead, if I could detirmine the
speed of the angel maybe I could find out what direction the pinhead is
travelling in.


"engsol" wrote in message
...
Great anology....i think 'oooph' should become a new lab
standard.
I think CN had one good point...engineers regard batteries as
a two-terminal device with a certain transfer function...chemists
working in the battery industry would see them totally differently.
Norm B

"Meindert Sprang" wrote in message
...
snip

The charge of a battery is the product of current x time.
True, but irrelevant

Both batteries are in series and one load is connected to the set,
operating
at 24V. Another load is connected across only one battery, operating at
12V.
So it is evident that one battery is discharged more than the other.
Yes, but you don't need the load - batteries will always have different
charge levels in individual cells, whether in the same case or not. It's
easy to measure the differences.

I start to charge the set in series, so the current through both batteries
is exactly the same.
No. You are failing to understand that the charging process is a chemical
reaction that converts energy into a differnt form.. The current flowing at
the positive and negative terminal of the whole string of cells is the same,
obviously, but the current that flows 'through' any cell is a complex result
of the conversion processes occurring inside the cells of which it is a
string. Each cell can be considered an energy sink. The amount of energy
imparted to each cell will differ, either within a single battery or within
a series of batteries. This is not a problem for the charging process. The
current flowing across any cell, or any group of cells, is most definately
not equal, and there is no reason it should be.

Since one battery is discharged more than the other and
the current throug both is the same, one battery must be charged longer
that
the other.
No. All cells are charged for as long as the charge is applied. It makes
no sense to say that one is charged longer than the other. Perhaps you
meant to say that some will continue to have the full potential applied when
they are not accepting additional energy - this is normal in any charging
process and causes no problem for the battery. It is, in fact, exactly what
happens when any battery is fully charged and a maintaining charge is being
applied. It is no different for the battery as a whole as it is for the
individual cells.

Exactly how am I going to achive that with the same current
through both batteries?
You do not achieve that, and you don't need to.

One battery will reach the full state before the other but is still being
charged with full current because the other battery hasn't reached the
voltage that corresponds with full charge.
One battery wil reach the full state before the other, like one cell will
reach the full state before some others. It's not a problem. It is not being
charged with full current because the 'load' that the system presents to the
charging process is reduced by the reduced charging requirements of the cell
(or cells) that have reached or are approaching full charge. The current
that can be absorbed by a bank of cells depends on the charge state of the
cells in the string, not the charge state of the most discharged cell.
That's why I said before that the system 'monitors' the state of the string
of cells, not individual cells. If the charge rate was controlled by the
most discharged cell then modern lead acid batteries, with typical
manufacturing differences, wouldn't last any time at all.

James Hahn wrote:

"Meindert Sprang" wrote

I start to charge the set in series, so the current through both
batteries is exactly the same.

No. You are failing to understand that the charging process is a chemical
reaction that converts energy into a differnt form.. The current flowing
at the positive and negative terminal of the whole string of cells is the
same, obviously,

Yes, indeed, obviously. And equally obviously the current flowing at the
positive and negative terminal of each individual cell in the string is
also the same. Surely you would not be daft enough to deny that!

but the current that flows 'through' any cell is a
complex result of the conversion processes occurring inside the cells of
which it is a string.

What exactly happens at the microscopic level may well be complex and
diverse, but the current passing through any surface you'd care to cut
through any cell will be the same.

Each cell can be considered an energy sink. The amount of energy
imparted to each cell will differ, either within a single battery or
within a series of batteries.

This is not in dispute.

The current flowing across any cell, or any group of cells, is most
definately not equal, and there is no reason it should be.

There is every reason it should be. It makes no difference whether
the load seen by a charging device is a string of resistors or of
battery cells, the current at every point in the circuit must be
equal at all times.

There is, however, no reason why the amount of energy absorbed by
each cell during charging should be the same.

One battery will reach the full state before the other but is still being
charged with full current because the other battery hasn't reached the
voltage that corresponds with full charge.

One battery wil reach the full state before the other, like one cell will
reach the full state before some others. It's not a problem.

It is a problem, because the fuller battery's internal voltage will
rise sooner than that of the not-so-full one, and so it will continue
to take a higher share of the monitored charging voltage applied to the
string. This not only means the less full one will take longer to
reach full charge but also that it's being charged at a suboptimal
voltage and so may never reach proper full charge, while the fuller
battery is being overcharged leading to a shorter life.

It is not
being charged with full current because the 'load' that the system
presents to the charging process is reduced by the reduced charging
requirements of the cell (or cells) that have reached or are approaching
full charge.

"Ronald Raygun" wrote in message
k...
James Hahn wrote:

"Meindert Sprang" wrote

I start to charge the set in series, so the current through both
batteries is exactly the same.

No. You are failing to understand that the charging process is a
chemical
reaction that converts energy into a differnt form.. The current
flowing
at the positive and negative terminal of the whole string of cells is
the
same, obviously,

Yes, indeed, obviously. And equally obviously the current flowing at the
positive and negative terminal of each individual cell in the string is
also the same. Surely you would not be daft enough to deny that!

but the current that flows 'through' any cell is a
complex result of the conversion processes occurring inside the cells of
which it is a string.

What exactly happens at the microscopic level may well be complex and
diverse, but the current passing through any surface you'd care to cut
through any cell will be the same.

Each cell can be considered an energy sink. The amount of energy
imparted to each cell will differ, either within a single battery or
within a series of batteries.

This is not in dispute.

The current flowing across any cell, or any group of cells, is most
definately not equal, and there is no reason it should be.

There is every reason it should be. It makes no difference whether
the load seen by a charging device is a string of resistors or of
battery cells, the current at every point in the circuit must be
equal at all times.

There is, however, no reason why the amount of energy absorbed by
each cell during charging should be the same.

One battery will reach the full state before the other but is still
being
charged with full current because the other battery hasn't reached the
voltage that corresponds with full charge.

One battery wil reach the full state before the other, like one cell
will
reach the full state before some others. It's not a problem.

It is a problem, because the fuller battery's internal voltage will
rise sooner than that of the not-so-full one, and so it will continue
to take a higher share of the monitored charging voltage applied to the
string. This not only means the less full one will take longer to
reach full charge but also that it's being charged at a suboptimal
voltage and so may never reach proper full charge, while the fuller
battery is being overcharged leading to a shorter life.

It is not
being charged with full current because the 'load' that the system
presents to the charging process is reduced by the reduced charging
requirements of the cell (or cells) that have reached or are approaching
full charge.

So how does all this techno babble answer the OP's question I wonder? :-)

ChrisR wrote:

So how does all this techno babble answer the OP's question I wonder? :-)

Well, it doesn't directly. The OP *should* know by now however, that CN
and all his drivel should be studiously ignored. But, to be on-topic, I
would suggest the following:

1. If the 12V device draws minimal current, and/or is to be in use only
sporadically, then tap one battery and don't worry about it. If you're
using a couple of amp-hours per day, and recharge fairly frequently, the
diffential in the batteries will be, IMO, negligible.

2. If the 12V device (VHF IIRC) is a significant load, you can always
build a simple voltage divider (the VHF should be input voltage tolerant
enough to handle the voltage sag during transmission) and run from both
batteries. The overall battery draw will, of course, be somewhat larger
since you'll dissipate heat in the dropping resistor. If multiple
devices are used, however, this approach quickly becomes problematic.

Keith