Jeff said:
Sorry, I don'[t think you have it quite right. "Current" is an
instantaneous rate of charge flow. Although formally defined in terms
of forces in wires, it is better understood as a change in charge, as
in coulombs/second. Since Coulombs can be thought of as a number of
electrons (6.24E+18), Amps are "electrons per second" ignoring the
constant factor. Amps-hours thus represent a number of electrons.
However, the spec sheet said "Average current consumption for 12 VDC
systems over 24-hour period" which is "Amp-hours/day" - for some
reason Kinch keeps ignoring this even though is is clearly stated. This
is measure of charge flow, simply scaled up by 24 from amperes.

snip


Measuring something is different from stating its instantaneous
property. Velocity is stated for a moment in time, but is real hard
to measure without considering a change in position over time, or by
using some other technique that considers time.


You've said (pretty obliquely) some of the same thing ("electrons per
second"), and I agree with your statement about measurement being
different than describing an instantaneous property.
Current is flow. Flow is not stagnant. Flow cannot be anything else
but flow. For flow to happen in this case, electrons have to move. When
they move, it is called "current". Think of a river - can "current" flow
without movement? You can describe the amount of electrons existing in a
conductor at any one instant in time as a snapshot of an amount of
electrons existing in a conductor, but that amount is the result of the
electrons having flowed through that part of the conductor during some
amount of time however small or large. Just measuring or calculating the
number of electrons present in a conductor is not a measure of current
in and of itself, because current is a measure or calculation of the
number of electrons having flowed through a conductor during a given
specific amount of time.

What you are describing is the *rate* of flow as a snapshot of some
instant in time. But to get that snapshot of the rate of flow, you must
first have current, measured in amp-hours. What you alluding to is not a
measurement, it is a description of a rate of measurement at one
instant. Mr. Kinch talked about a piece of equipment should be rated at
(x) amps, but the term *amps* is in this case a *new terminology*
contraction for amp-hours, or it wouldn't make any sense. We all assume,
consciously or unconsciously, when reading a current rating listed on
any equipment when listed as *amps* to actually be amps-per-hour (the
*rate*) which is the current standard convention.
The time used for your measurement, however, is irrelevant, it is just a
way to determine how many electrons have flowed through the conductor
during that time. So if you used average current over one hour, or one
day, or one year, etc., you still have the same exact same type of
measurement; amps-per-whatever. But average measurement does not
describe what the flow is at any one instant in time, which is what you
were alluding to.
Electrical "pressure" is the old terminology for voltage, described as
"potential". This is not current, but influences current as described by
ohm's law.
Charge is a different entity entirely and is not current.
Velocity is not current, but can influence current. The term can also
seem confusing. If you have a large diameter pipe and have 1 gallon per
hour of water flowing through it, and you have a very small diameter
pipe and have 1 gallon per hour flowing through it you will have two
very different velocities. But if current is the measurement of
units-of-something-per-time, then the *current* is the same in both
pipes, although the *pressure* will necessarily be different (just like
ohm's law). But if the velocity of current, that is, if electrons are
limited in the actual speed each can flow through a given conductor
regardless of pressure (IE: speed of light in a perfect conductor), then
the number of electrons that can flow through a conductor in a given
time is limited at least by the size of the conductor, regardless of the
pressure (voltage). So *velocity* can be an imprecise term to describe
current if you label the amount of current flow as speed of flow (speed
of each electron moving), rather than the total number of
electrons-per-unit-of-time. Of course, exceeding a conductor's ability
to pass a certain number of electrons in a given amount of time will
result in excessive heat which may result in damage, hence the need to
describe a conductor's ability to handle a specific *rate* of current
flow. Most conductors will destruct due to heat before actually
exceeding its max rate of flow of electrons. That is why cooling a
conductor allows more current to be applied through it before self
destructing.
When measuring current with a meter, all U.S. meters that I have seen
and used measure in amps per hour averaged. Meters cannot take a
snapshot in time, because no matter how short the cutoff, it is still time.
If you'd like, you are invited over to look at any number of textbooks
I have (several lockers full) that will describe it for you more
eloquently and completely than I will here. Although my textbooks are
written in the "old" language of electronics - you know; amp-hours,
cycles per second, etc.