Battery cable came off!

True, but nobody is suggesting that you start your car with a capacitor. At
issue was the batteries ability to absorb spikes from the alternator. Given
that, batteries do have capacitance. I don't know how much it should be to
be effective though, but its there.

 

I feel like Kerry... "What I meant to say is, 'Uh, the battery is
nothing more than THE EQUIVALENT of a large capacitor.'"

I think that it's time for a belt of Pinch!

JT

 

I feel like Kerry... "What I meant to say is, 'Uh, the battery is
nothing more than THE EQUIVALENT of a large capacitor.'"

I think that it's time for a belt of Pinch!

JT

 

A car battery has many farads of capacitance. In other words,
it's a very stout capacitor..
MK

 

A car battery has many farads of capacitance. In other words,
it's a very stout capacitor..
MK

 

A car battery has many farads of capacitance. In other words,
it's a very stout capacitor..
MK

 

A car battery has many farads of capacitance. In other words,
it's a very stout capacitor..
MK

 

Sure they do. A pair of wires running side-by-side do too. Not enough to
consider them functional "capacitors" though.

Yes, they store energy... but not ELECTRICAL energy. That's generated out of a
chemical reaction.

 

Sure they do. A pair of wires running side-by-side do too. Not enough to
consider them functional "capacitors" though.

Yes, they store energy... but not ELECTRICAL energy. That's generated out of a
chemical reaction.

 

Not even close. The smaller the plates of a capacitor, the less the
capacitance. The further apart they are, the less the capacitance. Lead-acid
battery plates are EXTREMELY small and EXTREMELY far apart compared to a true
capacitor's.

If you were to drain the water from a battery and measure the capacitance, I
suspect you'd find it in the low microfarads, if not picofarads.

 

Not even close. The smaller the plates of a capacitor, the less the
capacitance. The further apart they are, the less the capacitance. Lead-acid
battery plates are EXTREMELY small and EXTREMELY far apart compared to a true
capacitor's.

If you were to drain the water from a battery and measure the capacitance, I
suspect you'd find it in the low microfarads, if not picofarads.

 

I didn't say he was wrong.

 

I didn't say he was wrong.

 

I've seen such a "pair of wires" literally used in a electronic circuit for
a capacitor,by DESIGN.

Engineers modeling components like a battery for computer aided design,the
battery model definitely has capacitance.
Even the electronic symbol for a battery is two plates,just like a
capacitor.

yes,it is electrical energy. What other sort of energy would it be?

differing from electric charges generated by friction;static electricity.
They both are ELECTRIC charges,though.Both are electric current,too.

 

I've seen such a "pair of wires" literally used in a electronic circuit for
a capacitor,by DESIGN.

Engineers modeling components like a battery for computer aided design,the
battery model definitely has capacitance.
Even the electronic symbol for a battery is two plates,just like a
capacitor.

yes,it is electrical energy. What other sort of energy would it be?

differing from electric charges generated by friction;static electricity.
They both are ELECTRIC charges,though.Both are electric current,too.

 

Sure, usually in RF circuits where very tiny amounts of capacitance are needed.
Sometimes a "capacitor" even exists as just a pair of interlaced traces on the
circuit board. And in high-frequency designs, particularly network cables, the
inherent capacitance of the wires must be taken into account.

That doesn't mean a pair of wires *are* "a capacitor", or that in most cases the
inherent capacitance is of any concern or use, any more than the capacitance in
a lead-acid battery is of any concern or any real use.

Well, usually a series of stacked plates of alternating lengths. But that's
true of the the symbol for ANY battery, including your good old carbon-based
flashlight batteries.

They don't STORE electrical energy. When you charge a battery, the electrical
(kinetic) energy you feed into it creates a chemical reaction; the electrical
energy is converted to chemical (potential) energy. When not charging, the
inverse chemical reaction converts chemical energy back to electrical energy.

In a very simpistic sense, sure, a battery is "storing" electricity (as opposed
to "electrical energy"). At the physics level, it's merely converting one form
of energy to another.

 

Sure, usually in RF circuits where very tiny amounts of capacitance are needed.
Sometimes a "capacitor" even exists as just a pair of interlaced traces on the
circuit board. And in high-frequency designs, particularly network cables, the
inherent capacitance of the wires must be taken into account.

That doesn't mean a pair of wires *are* "a capacitor", or that in most cases the
inherent capacitance is of any concern or use, any more than the capacitance in
a lead-acid battery is of any concern or any real use.

Well, usually a series of stacked plates of alternating lengths. But that's
true of the the symbol for ANY battery, including your good old carbon-based
flashlight batteries.

They don't STORE electrical energy. When you charge a battery, the electrical
(kinetic) energy you feed into it creates a chemical reaction; the electrical
energy is converted to chemical (potential) energy. When not charging, the
inverse chemical reaction converts chemical energy back to electrical energy.

In a very simpistic sense, sure, a battery is "storing" electricity (as opposed
to "electrical energy"). At the physics level, it's merely converting one form
of energy to another.

 

When you DRAW current from a battery,how does the chemistry knows to start
converting chemicals to electric current?
Where does that initial current come from?


Simple,the *charge on the plates* decreases and the chemical reaction adds
more electrons to fill the depletion of the plates charge.

 

When you DRAW current from a battery,how does the chemistry knows to start
converting chemicals to electric current?
Where does that initial current come from?


Simple,the *charge on the plates* decreases and the chemical reaction adds
more electrons to fill the depletion of the plates charge.

 

Sure. The capacitance I mention is more of an apparant capacitance.
It's not true capacitance per say, but the normal operating car battery
does provide a large apparant capacitance to the system. But this would

not be the case with a non functioning battery.
I use car and deep cycle marine batteries to run radios here in the
house.
My chargers are unfiltered, but yet I have little noise to my radios.
The use of my battery as a cap is a bit different in operation vs a
true
capacitor, but the final apparant filtering is still there. If the
battery were
not acting as a cap of sorts, I would have hash and trash out the
kazoo..
I don't know if this makes any sense, as it's hard for me to describe
stuff
like this off the top of my head..
As a quite dangerous test you could try running a car radio off the
running
alternator with no battery connected. I bet it will be quite noisy,
fairly
unregulated as far as volume, etc vs rpm. IE: if the rpm dropped too
low,
the radio might totally drop out due to the low voltage.
Hook the battery up, and all is smoothed out. Both as far as
regulation,
and also filtering. If thats not acting like a large "apparent"
capacitor,
I don't know what is. The operation is different, but the end results
are
about the same. This is not something I've really thought about too
much,
but I've always considered the usual operating car battery to have many
farads of capacitance, at least as far as overall function. Maybe not
true
in the strict sense, as far as true caps go, but as far as the end
results
of placing it in the system. I dunno if this makes any sense or not..
:/
MK