There are no forum members that confuse A and AH.

[SailingHarmonie]

Originally Posted by Baronkrak

W = Voltage x Amperage
Is incorrect.

W = V x A x p.f.
VA = V x A

Gord is not confused.

He is not the one who started this discussion when you criticized the thread that was discussing DC power for ignoring power factors...

He is not the one who demanded to know why a DC circuit would have a power factor of 1.0.

You can keep it going, but you are not impressing...

[Baronkrak]

Originally Posted by Baronkrak

And how did you calculate that power factor of "1.000000" ?

That was the question.

[team karst]

Lets say i have a 12V battery that had a 20 A dc current due to a fixed resistive load and there was also variable load on that wire, lets say a old fashioned bell, that switched between zero and 10 Amps. So the battery sees a total current that changes from 20 to 30 A.
Is this an ac current or a dc current? Keep in mind the battery will only supply a positive current with these loads.

[Chotu]

Originally Posted by team karst

Lets say i have a 12V battery that had a 20 A dc current due to a fixed resistive load and there was also variable load on that wire, lets say a old fashioned bell, that switched between zero and 10 Amps. So the battery sees a total current that changes from 20 to 30 A.
Is this an ac current or a dc current? Keep in mind the battery will only supply a positive current with these loads.

This is like a philosophical question. I love it!

My answer is it is not alternating current. Alternating current follows a sine wave or other type of situation where the polarity reverses on the conductors.

This is a variable DC current situation.

[team karst]

True it is variable current.

In fact, the example given has a current with frequency components at 1x, 3x, 5x etc of the bell frequency. Square waves having odd harmonic frequency spectrum.
So we have many frequency currents riding on top of dc.
Does this affect the answer?

[Chotu]

Originally Posted by team karst

True it is variable current.

In fact, the example given has a current with frequency components at 1x, 3x, 5x etc of the bell frequency. Square waves having odd harmonic frequency spectrum.
So we have many frequency currents riding on top of dc.
Does this affect the answer?

I’m still going to stick with no. Not alternating current.

Having never even thought about it before, the definition of alternating current is in the first word. Alternating.

The polarity of the conductors have to alternate to meet the definition.

If all of the variability and waveforms are above the 0V threshold line and don’t go negative, it’s still DC, although some very complex waveforms.

At least that’s the answer I’m sticking with ha ha

[sailingharry]

Originally Posted by GordMay

Power factor is defined as the cosine of angle, between the voltage phasor and the current phasor.
pf = CosØ
In a DC circuit, the current and voltage are always in phase, which is another way of saying that the phase difference, between the current and voltage, is zero degrees; and the cosine of zero, is one.

Gord,

He's either clueless or being intentionally obtuse. As they say "don't feed the trolls."

[Baronkrak]

He still like you, associates Direct Current with pf.

Originally Posted by GordMay

Power factor is defined as the cosine of angle, between the voltage phasor and the current phasor.
pf = CosØ
In a DC circuit, the current and voltage are always in phase, which is another way of saying that the phase difference, between the current and voltage, is zero degrees; and the cosine of zero, is one.

Originally Posted by sailingharry

….. the pf in direct current is 1.....

Originally Posted by Stu Jackson

……..

Whether people know or don't know, the point is that many keep using and typing the wrong unit of measurement.


That's the only point.

[wyb2]

Originally Posted by Baronkrak

In any case VA should be used for direct current.
Not to worry, even Victron uses incorrectly W for VA. (BMV 712)
Beginner common mistake.

Originally Posted by Baronkrak

W = Voltage x Amperage
Is incorrect.

W = V x A x p.f.
VA = V x A

Originally Posted by Baronkrak

And how does “Basic power factor fundamentals" applies to Direct Current circuitry ?

Originally Posted by Baronkrak

There is no pf in direct current.

VA = V x A applies.

Originally Posted by Baronkrak

He still like you, associates Direct Current with pf.

Everyone is confused because you are talking about VA, and everyone knows VA is only seen/used in practice when dealing with AC.

In DC:
W=V*A
VA=V*A

In AC:
W=V*A*pf
VA=V*A

In DC, W is by far the more standard notation. Saying it's incorrect is...incorrect.

"In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical circuit)."


"The volt-ampere (SI symbol: VA,[1] sometimes V⋅A or V A) is the unit of measurement for apparent power in an electrical circuit. It is the product of the root mean square voltage (in volts) and the root mean square current (in amperes).[2] Volt-amperes are usually used for analyzing alternating current (AC) circuits. In direct current (DC) circuits, this product is equal to the real power, measured in watts.[3]"

[Bowdrie]

Originally Posted by Jamme

So:

- Ah in a battery is the equivalent of how many pretzels I have in a bag. 🥨
- Amps is the equivalent of how fast I’m gonna eat these pretzels. 🥨 🥨 🥨🥨
The same pretzel bag can last an hour or a whole day, depending on how pretzel-hungry I am.
Scientific enough?
[emoji3][emoji253] ✌️ ☮️

That pretty much nails it.
I came to a "Scientific enough" conclusion in regard to "power factor" for AC motors.
At the 0/180-degree points there are electrons that are just too lazy to shoulder much, (if any,) of the burden of work.
Therefore, the ones at the other positions on the sine wave are forced to carry a heavier load.

[GordMay]

Originally Posted by Baronkrak

He still like you, associates Direct Current with pf.

Originally Posted by GordMay

Power factor is defined as the cosine of angle, between the voltage phasor and the current phasor.
pf = CosØ
In a DC circuit, the current and voltage are always in phase, which is another way of saying that the phase difference, between the current and voltage, is zero degrees; and the cosine of zero, is one.

Originally Posted by Baronkrak

And how did you calculate that power factor of "1.000000" ?

I don’t associate Power Factor with Direct Current; because DC has no PF component.
I, merely, replied to the question, as to how I would ‘calculate’ that proposition - a mathematical proof.

[s/v Jedi]

wyb2 and Gord are 100% correct. For DC we talk about Watts, never VA.

The important bits to remember:

It is very difficult to measure the state of charge of a battery. The best thing to do is count how much energy comes in and goes out using a fully charged battery as the reference point. This is called “Coulomb counting” and it is what a Victron battery monitor does. The difficulty is that it needs to recognize that “fully charged” reference point and the manual describes how to program this.

When a battery is fully charged, it holds a certain amount of energy. This is expressed in Watt-hour, Wh or kilo-Watt-hour kWh. The “W” is a capital letter because it refers to the inventor of the unit, James Watt.
You can calculate this amount of energy a battery can hold when you know the nominal voltage and the Ah rating. For example, a 400Ah LiFePO4 cell has a nominal voltage of 3.2V so it can hold 3.2 x 400 = 1,280 Wh or 1.28kWh. If you connect four of those cells in series for a 12V battery then you can simply multiply that by four, so the battery becomes 4x 1.28 = 5.12kWh. If you connect 8 cells in series for 24V, it becomes 10.24kWh and this shows why it is so good to go higher in voltage: you multiply power and energy storage without increasing amperage.

This also shows why it doesn’t make sense to use Ah instead of kWh: both batteries are 400Ah while the 24V is is twice as big, which is precisely indicated by the kWh rating.

So, use Ah to find the state of charge of a battery but use Wh to describe the amount of energy stored, used or generated.

[JBP]

Originally Posted by Jamme

So:

- Ah in a battery is the equivalent of how many pretzels I have in a bag. 🥨

- Amps is the equivalent of how fast I’m gonna eat these pretzels. 🥨 🥨 🥨🥨

The same pretzel bag can last an hour or a whole day, depending on how pretzel-hungry I am.

Scientific enough?
[emoji3][emoji253] ✌️ ☮️

If the pretzels at the bottom of the bag have lost their salt, let's call it their "Pretzel Factor", you can still have a satisfying result if you alternate your pretzel selection between the bottom and top, or "Alternating Consumption". If all the pretzels have the same amount of Pretzel Factor then you can eat them straight off the top or "Direct Consumption ". This proves AC must address PF, but DC does not.

The big question is, are you going to share those pretzels?

[Baronkrak]

Originally Posted by wyb2

Everyone is confused because you are talking about VA, and everyone knows VA is only seen/used in practice when dealing with AC.

Everyone? Really

Originally Posted by wyb2

In DC:
W=V*A
VA=V*A

In AC:
W=V*A*pf
VA=V*A

That is confusing because the symbol W is being used in two different formulas

In DC:
VA=V*A

In AC:
W=V*A*pf

This is the way.

Originally Posted by wyb2

In DC, W is by far the more standard notation.

No wonder people get confused, definitely incorrect.

[Chotu]

Originally Posted by Baronkrak

Everyone? Really



That is confusing because the symbol W is being used in two different formulas

In DC:
VA=V*A

In AC:
W=V*A*pf

This is the way.



No wonder people get confused, definitely incorrect.

In DC, the traffic can be absolutely horrendous and it’s not a fantastic destination by boat either. It’s quite out of the way. VA is known to have terrible traffic as well but only on the VA/DC border. A lot of people think VA=DC , but VA is fairly rural, as is W VA.
However, considering all the traffic and convenience by boat as factors,, Watts the formula for the best place to visit? … pffffff! Might as well just go to AC and enjoy yourself! Easier to get to by boat too!

No one should be confused. This is all perfectly gin clear. Like the water in the Chesapeake