Serial battery configurations

[Diamon]

So, I know that if I wire batteries together in a serial configuration the voltage will increase to a total of the combined voltages of the batteries. But how does it work?
My train of thought is that batteries contain two chambers (+ and -) and the electrons want to travel from - to + in order to create an equlibrium. So you make a connection between them with something in between that is then powered by the passing electrons. But that would mean that if I stack a few betteries on top of each other the electrons would simply travel from the topmost section to the one at the bottom of the stack while the batteries in between is shorted out instantly. This is obviously not how it works so there must be something I'm missing with this theory. Does anyone of you know how it works?

-Diamon

[Yeticorn]

From my understanding, chemical reations in a battery can only happen so fast. This is why batteries have a maximum current they can produce.

Ex: A 500 milliamp-hour battery can in no way produce a 30,000 milliamps for 1 second. The chemicals just don't react fast enough.

Also, it's my understanding that stacking batteries (i.e. serial) simply allows current to flow while the electrons themselves remain local - they simply become normalized and lose charge.

Information and examples are from here, I'd recommend reading the article. It's actually very interesting Great site for looking up general information (it's where I got the above information

[Diamon]

That's not what I was asking but thanks anyways.

Also current IS electrons rushing past in a conductor.
And a power source can produce an infinite amount of ampere, until the conductor evaporates that is

[Yeticorn]

I guess I'm not understanding the question.

[Konrad]

There are limits, of course.

Every cell has an internal resistance (impedance, actually, if you want to be technical, due to the miniscule capacitive reactance). Very little, routinely ignored in almost all practical applications. But when you put a large number of cells in series (ie, the definition of a battery) you'll eventually reach a threshold of diminishing returns as the added voltages and resistances place limits on the maximum load you can draw. This usually affects things like radio transmitters significantly but has no real impact on things like digital electronics. The same rules govern stacked solar cells, which is why you'll never see any that can put out large voltages.

You can google battery types or battery engineering to learn more than you'd ever want to know in disgusting detail. Or google electronics, physics, or chemistry to learn what happens when electrons move around. Your question is unclear about how sophisticated the answer needs to be.

[x88x]

Are you asking about application or the physics behind it?

Application:
Voltage (V) builds in series, current (A) and capacity (Ah) builds in parallel. Fortunately, it's not like capacitance and resistance, so it's actually just a straight linear combination. Also, voltage is not affected by building in parallel, and current and capacity are not affected by building in series.

Physics:
How the affect is achieved is, of course, different for all the different chemistries, but the general top-down explanation is this:
As has been mentioned, electricity is just electrons moving from molecule to molecule along a conductor. You can think of batteries as just a way to store a bunch of electrons for later use. Almost every battery is actually a bunch of smaller stacks (usually) in series (as Konrad mentioned), so in effect you're just extending the system when you put more batteries in series. It goes like this: voltage is the amount of electrons that can cross over the battery (or pack), current is the rate at which those electrons can cross, and capacity is the amount of electrons that can be held in reserve.

Halfway between:
There are five important stats for a battery, and they're all connected:
1) Voltage, measured in Volts (V).
2) Current, measured in Amps (A).
3) Capacity, measured in Ampere-hours (Ah).
4) C-rate, measured in...C's...? It's more of a ratio than anything else.
5) Internal resistance, measured in Ohms (symbol is the Greek capitol letter Omega...nothing in the font I'm using now, sorry).

These five stats are bound by two equations:

The two stats that are most commonly listed on a battery are the voltage and capacity, though depending on the application, the C-rate or max current is often listed as well. Oh, I forgot to mention above, but the current in the equations is always the max current possible. Some batteries will also have two different C-rates, one for max continupus and one for max peak.

C-rate is the one that I found most confusing at first, but it is actually very simple. It gives you the max current, using the equation above, and it also tells you how long until the battery is depleted if it is being drawn at max current. Just divide an hour by the C-rate and it would take that many minutes, regardless of what the capacity or max current are. For example, a 5C battery at max draw would drain completely in 12 minutes. Because of this, C-rate is also frequently used as a measure of the rate at which battery energy is being used. For example, you might have a battery rated to 10C, but at any given point in normal use you might say that you are drawing power at 0.5C.

In case you're wondering, yes, there is actually a reason I know all this off the top of my head. I've been spending the last few weeks researching battery and electric motor tech for some projects I'm lining up to experiment with electric vehicles.

Oh, and btw, Yeticorn, the battery that you described would actually be possible with some of the more robust chemistries. 30A out of a 500mAh battery would be a 60C rate, completely within the realm of possibility for a 1s burst. None in quite so small capacity, but any of these would do it.
http://www.hobbyking.com/hobbyking/s...8&ParentCat=85
http://www.hobbyking.com/hobbyking/s...7&ParentCat=85

EDIT:
I just reread you OP. Diamon, and I think I see the problem. You're looking at the circuit backwards. The electrons don't move primarily from one end of the battery, through the circuit, to the other end, they move through the battery and everything else is a side-effect of this. Think of the battery like a water pump, it provides the motive force for the system, and 'powers' the other things in the water line. In fact, a pump really is a great parallel. The larger diameter the in/outtake, the higher the voltage, the higher the pressure, the higher the current.

[Diamon]

Thanks for the answers, they were not quite what I was looking for but my question was hard to understand, and to ask properly.

The thing I wanted to know was why the voltage increases when you wire batteries in a serial configuration. And if you think about it it doesn't really seem to make sense since the electrons doesn't pass through all of the batteries. They just flow from the battery to the bottom. However electrons doesn't need to be in contact with each other to have force. The magnetic fields will add up and increase the voltage (one of my teachers could explain it).

Anways, +rep!

[x88x]

If you want a detailed explanation, check out this site.
http://www.allaboutcircuits.com/vol_..._11/index.html

You say that the electrons don't pass through all the batteries...where are you getting that information? Because that's exactly what they do. The electrons are pushed by the battery 'out' of the + terminal, through the connecting circuit, in an attempt to equalize with the - terminal (ground). The more batteries you stack in series, the more electrons are 'pushed' out of the stack. Like Konrad and I mentioned, almost all batteries are a combination of smaller stacks (usually in series, but not necessarily), so the behavior of multiple batteries in series still operates on the same principle.

What I think you're referring to with the magnetic fields is electron flow. Electron flow is easiest to explain if you think about an electric conductor 1 atom wide. Basically what happens is that a voltage source (in this case, a battery) pushes extra electrons onto the conductor. This causes the first atom in line to accept more electrons than it should normally have, making it unstable. This unstable state is fixed by an equivalent number of electrons being pushed off of the atom in the opposite direction. Remember, there is still a positive 'pressure' of electrons in the direction of the voltage source. Also, from Newton's Third Law of Motion, we know that every action has an equal and opposite reaction. That still applies in atomic physics, the forces are just really small for each reaction. Anyways, the first atom pushed atoms off onto the second atom. The process then repeats itself with the second atom, and every atom down the line, eventually resulting in (ideally) the same number of electrons getting pushed off the last atom in line that were pushed onto the first atom in line. There are, of course, losses in real scenarios, but that's what happens in an ideal conductor. One additional thing that is not readily apparent, these excess electrons are only passed along the surface molecules of a material. This is why twisted and braided wires are more common than solid strand, and why to push higher current levels (ie, more electrons in a given amount of time), you need higher gauge wire (ie, more surface area).

[Konrad]

Water analogies are commonly used when explaining basic electronics.

Think of it as having a cylinder of water with a small hole in the bottom. Some water is always going to pour out, although the water molecules at the top are quite unlikely to be the ones that come out first. (Impossible to track the behaviour of individual molecules, or electrons, without impossibly exotic quantum mechanics that don't actually give you the answer anyhow.)

If the container gets taller, ie holds more "weight" of water it'll "push" more water out of the hole, this is basically what happens when you increase a voltage by stacking batteries. If you instead make the tiny hole at the bottom a bit bigger then you'll get a wider flow of water, more water molecules per second as it were, and the electronic equivalent would be increasing the current (amps) instead, by wiring your batteries in parallel instead.

Hope that helps. I always hated the water analogies anyhow.

[x88x]

Think of it as having a cylinder of water with a small hole in the bottom. Some water is always going to pour out, although the water molecules at the top are quite unlikely to be the ones that come out first.

For clarification, the bottom of the cylinder in this example is the + terminal (just wanted to point that out, since + is normally thought of as the top of an image).