Quite true. Amps or fractions of an amp is the rate (or speed) of flow in use. Or the “speed” referenced above. AH or fractions is the capacity available over time. Or the amount of total energy available measured over time. So, if specs are accurate, a 1000 mAh (1 Amp hour) cell could deliver 1 amp of current for one hour before being drained.
So yes, @ the last katun has it just exactly backwards.
How can an A be a speed if it lacks the time factor?
How can Ah be a static capacity if the expression is A/h? (Ampere divided by hour).
I can hold a battery of 80A capacity “still,” it cannot give me a ” speed of flow in use.”
the “amount of total energy available (A) measured over time (h)” is a velocity, just as distance measured over time is a velocity (mi/h), it is the energy flowing in a given amount of time.
However, let’s do a small elementary problem: If I have a 12-volt battery and apply a “load” of 4A to it for one hour (4Ah load) or let’s say even 48 watts; what capacity does my battery have? If, as you say, Ah indicates the capacity of the battery (i.e., the capacity from when it is charged to when it is discharged), the solution will be simple and will be one.
AMPS is current at an instant in time. So it is electrical flow at one instant. Not over a given time. Let’s call it volume at an instant. So maybe “speed” is not a perfect label. But certainly Ah is not speed in any sense. Again, current is an instantaneous thing. So lets throw out “speed” entirely. But this would match better to your original statement. But still, I agree, it is wrong. I was trying to simplify things relative to your OP.
Amp Hours is the number of amps over a specified time. In batteries this is often equal to rated capacity.
Amp Hour (Ah) = Current (I) x Discharge Time (T)
The only way to associate “speed” to Ah is by using it relative to the length of time to discharge a source. I guess for this discussion we are talking about batteries, yes?
So if we are talking “speed, it will only be relative to the ”speed” that it takes (X amount of time) to discharge a specific battery at a given flow rate (Amps). So speed in this case is not the volume of electron flow (Amps). But rather the speed it takes to discharge a source (battery) at a given flow rate.
So, to recap, current is instantaneous flow. Ah is current for a given amount of time.
BTW Ah is also used, when converted to Watt hours to calculate energy use over time. Like most meters for electrical use billing.
Thank you for continuing this dialogue.
I think I have found the “crux” of the matter; we have, we refer to, two different models of battery evaluation; the view you propose is Ampere X hour (A*h or Ah) whereas I see it as Ampere/hour (Ampere divided by hour). as, for example, at this link: .
I consider the unit of measurement of current to be solely the Ampere (A), and not the set Ah, and for me it is easier to determine the capacity of a battery (which then are the consumption capacities) by dividing its rated capacity over a time, rather than multiplying it by the same.
I think it’s just the way of looking at things.
That it is a way of looking at things is also proffered on the same page, where, further down, Wh is described (specifying: “watt-hours” and not watts X hours) and where it is described as, “The amount of electrical energy consumed by a circuit over a period of time.” and consumption is a subtraction, subdivision and transformation of resources and not their multiplication.
The same formula you propose to me [Amp Hour (Ah) = Current (I) x Discharge Time (T)] has “Discharge Time” as its term, that is, a subtraction, a splitting of resources over a period of time, going from being “power” to being heat, motive power, light, usually even simultaneously, etc., and separating from the energy left to the battery; certainly not their multiplication.
But as I repeat, it is just a way of understanding, and expressing differently, the same thing
As the other poster already noted, Ah is not Amps divided by time. It is Amps (current) multiplied by time. For example,a battery with a capacity of 3,000 mAh will theoretically deliver 3,000 mA of current for 1 hour, or 1,000 mA of current for 3 hours, etc.
Look at any battery designation: it will state capacity in mAh, not in mA.
Perhaps a cogent argument. I guess I can see your logic. But, it is just not the accepted way used in discussion of electrical terms. In other words it is not the standard that the majority of rest of folks on BLF (and probably in the rest of the world) find to be correct. So it tends to confuse people.
Yes, I comprehend, I will adjust.
Out of curiosity I can offer you a dialogue that is very technical and human at the same time, where both the term Amps (Amps) and “amp-hours” (transcribed like this) are used. the reproduction (drawing) of the instruments reproduces only “Amps” or “A”, in general I note that Amps, when “moving” are referred to as Amp-hours, when “static” only as Amps or Amps and that the semantics used is more “formal” from Earth.
Is the transcript of the difficult time experienced by Apollo 13, where battery and power management played a key role:
https://history.nasa.gov/afj/ap13fj/21day5-batterycharge.html
Looking at the drawings their instruments are ameters, so they say amps because they’re displaying the current draw (and the charging current), not the capacity/volume of the battery.
I see nothing in the NASA document to support your argument.
Maybe there’s a good reason why this convention was settled on, maybe there isn’t but it’s what we’ve got so might as well all be on the same page.
Not to stay a convention can’t and shouldn’t be changed if there’s something wrong with it, but if we can’t replace the BS Gregorian calendar with something that makes mathematical sense I wouldn’t hold out much hope for swapping the meanings of A and Ah, W and Wh.
I have started looking for a source of fresh-dated Energizer Lithium AAs. These are primarily for my earthquake cache, so shelf life matters.
Had the disappointing experience of buying a bunch of them to Amazon recently and receiving cells dated 2027 — making the claimed 20 year shelf life rather meaningless.
If you are close to a Sam’s Club, they should have the lithium batteries that are fresh. Ya, I know , you have to be a member. But you might ask some friends if they are. And they have the best prices of anywhere. Then come in 18 count, I believe, and that comes out to $1.97 for either AA’s or AAA’s. Hope you sent back the old ones from Amazon. Sometimes Sam’s will have cheap offers to join. I believe last years around Christmas time, they were offering $6.00 memberships for a year. (I could be wrong, but it a deal).