Impress your friends by using correct units and abbreviations

[Zil]

Please explain why watt hours is a better measure of amperes that can be pulled from a storage battery.
My thinking is 1000W is 71 amperes at 14 volts and higher amperes as the battery voltage drops closer to 12 volts. Storage batteries store and accept amperes. The storage capacity of a storage battery is amp hours. Watt hours vary with battery voltage. Amperes in or out don't.

And yes. watts are power used by the device, doing Work. to quote wiki "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)," 745.7 watts is one horsepower. Again work.

Often spell check on this and other forums will not recognize some "whole" words and ask for a hyphen. I think as humans we can recognize a hyphenated word with no confusion.

The amp hour number rating posted on a battery is determined how?

a? A? eh? On an electrical forum is the capitalization of this all that important? I do appreciate the problem with alternating current and air condition.

Na. We be too pedantic, yes? correct use?
Wait wait don't ban me again. I promise to endeavor to use the correct initialism, acronym, punctuation, and capitulation.
for a while anyway..
And I will not ask anymore questions.
Just to be mean, I will post the entire long link from Amazon from time to time.

 

[Warpspeed]

I once worked for a company that shall forever remain nameless, but we were designing safety critical systems used to move large numbers of people...

Anyhow, the Chief quality control honcho once told me that we only check documents and reports for correct spelling, font, width of margins, and that documents absolutely must conform to the official template. We never check facts, figures, or actual content.

So total nonsense gets a pass. But woe betide anyone that dares to submit something with a slightly displaced heading.

 

[wattmatters]

Please explain why watt hours is a better measure of amperes that can be pulled from a storage battery.

Because not all batteries operate/supply the same voltage.

100 Ah tells me nothing about a battery's storage capacity. I also need to know the voltage of the system, and there are a multitude of battery voltages in use.

2.0 kWh tells me how much energy storage capacity a battery actually has and is directly correlated with how much work can be performed by the energy supplied by that battery.

 

[stienman]

Please explain why watt hours is a better measure of amperes that can be pulled from a storage battery.
My thinking is 1000W is 71 amperes at 14 volts and higher amperes as the battery voltage drops closer to 12 volts. Storage batteries store and accept amperes. The storage capacity of a storage battery is amp hours. Watt hours vary with battery voltage. Amperes in or out don't.

To be fair, AH changes according to the discharge rate, so even your method of listing both the AH and Voltage separately don't give honest capacity information.

Properly calculated watt hours include the voltage drop, and are an integration of the area under the curve formed by a specified discharge rate, such as 1C, or 0.1C. So you have three input variables to yield one number, and no manufacturer choose consistent conditions which would allow us to fairly compare cells with each other using only watt hours. I don't know of an ISO or similar standard that would make this easier.

Most people calculate it simply as the typical steady state voltage times the AH, and this gives a general method to compare with other similar batteries. If you want to compare across chemistries, or wildly different discharge/charge rates then you have more work to do. But for a generic "This cell holds more than this one by approximately 5 times" or similar, the simple method works fairly well.

But that's why using correct units is important - they immediately tell the user that either they have all the information needed, or that there is information or variables that might affect the number which might matter in their decision or usage, and they can look up or test according to their needs if the single number with its proper units doesn't match their usage.

 

[12VoltInstalls]

AH changes according to the discharge rate

Yup. Watt hours are useful and necessary but there’s not a static baseline convention for that. Though from what I gather lithium is a linear output, lead is not.

 

[Supervstech]

Please explain why watt hours is a better measure of amperes that can be pulled from a storage battery.
My thinking is 1000W is 71 amperes at 14 volts and higher amperes as the battery voltage drops closer to 12 volts. Storage batteries store and accept amperes. The storage capacity of a storage battery is amp hours. Watt hours vary with battery voltage. Amperes in or out don't.

And yes. watts are power used by the device, doing Work. to quote wiki "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)," 745.7 watts is one horsepower. Again work.

Often spell check on this and other forums will not recognize some "whole" words and ask for a hyphen. I think as humans we can recognize a hyphenated word with no confusion.

The amp hour number rating posted on a battery is determined how?

a? A? eh? On an electrical forum is the capitalization of this all that important? I do appreciate the problem with alternating current and air condition.

Na. We be too pedantic, yes? correct use?
Wait wait don't ban me again. I promise to endeavor to use the correct initialism, acronym, punctuation, and capitulation.
for a while anyway..
And I will not ask anymore questions.
Just to be mean, I will post the entire long link from Amazon from time to time.

Easy...
Wh is a capacity or usage unit with no confusion.

Ah is a calculation based on the voltage of the work being performed.

You wouldn't believe the number of times I've been asked how many Ah do I need to operate a 10A device...

No additional info.


So, is that 10A at 12V? 120V? 240? How long will the load be operating? What Voltage is the battery? Because all that is needed to give an answer in Ah...

In Wh the answer is easy...

How mamy Wh battery is required to operate a 300W appliance for 24h?

 

[WYtreasure]

300 x 24 = 7200

 

[Warpspeed]

I don't think it really matters all that much. There are so many different battery types and applications these days, and for some applications a lot more information is required to make a sensible choice of battery.

Some batteries such as watch and memory backup batteries might be expected to last for a year to several years.
Discharge at 1C or amp hours capacity would be just silly for that. Microamp years maybe ??

Something like cranking amps for an engine starting battery, or peak discharge for a Taser weapon or defibrillator, might be a more useful indication, if there is a properly defined testing method.

Most applications fall somewhere in the middle, but we are still left with specifying in different units with possibly different measurement methods more appropriate for different applications.

 

[WYtreasure]

MWBC: MultiWire Branch Circuit

Commonly written as "multi-wire branch circuit" or "multiwire branch circuit".

Simply defined as: A multiwire branch circuit consists of two or more ungrounded (hot) conductors and one grounded (neutral) conductor.

Yes, no, sort of? ?‍

 

[rmaddy]

Let's keep in mind that this thread is not a general discussion of random acronyms. Please keep this thread related to the correct use of electrical units and misused abbreviations.

There is an acronyms page on this site. If you have a relevant DIY solar acronym to suggest then it should go that page:

Commonly used Forum Acronyms & Abbreviations

Solar is befuddling enough! Why use acronyms? Well, we're lazy typists.... :LOL: xSyP - e.g., 2S2P, shorthand for how many cells in Series (S) and Parallel (P). A - Amperes or amps. A measure of current. See warning. AC - Air Conditioning, sometimes A/C. AC - Alternating Current, a waveform...

diysolarforum.com

Thanks

 

[Shimmy]

MWBC: MultiWire Branch Circuit

Less commonly referred to as a "Baseball"

 

[burgerking]

AWG	Diameter	Diameter	Area
[inches]	[mm]	[mm2]
0000 (4/0)	0.4600​	11.6840​	107.0000​
000 (3/0)	0.4096​	10.4038​	85.0000​
00 (2/0)	0.3648​	9.2659​	67.4000​
0 (1/0)	0.3249​	8.2525​	53.5000​
1	0.2893​	7.3482​	42.4000​
2	0.2576​	6.5430​	33.6000​
3	0.2294​	5.8268​	26.7000​
4	0.2043​	5.1892​	21.2000​
5	0.1819​	4.6203​	16.8000​
6	0.1620​	4.1148​	13.3000​
7	0.1443​	3.6652​	10.5000​
8	0.1285​	3.2639​	8.3700​
9	0.1144​	2.9058​	6.6300​
10	0.1019​	2.5883​	5.2600​
11	0.0907​	2.3038​	4.1700​
12	0.0808​	2.0523​	3.3100​
13	0.0720​	1.8288​	2.6200​
14	0.0641​	1.6281​	2.0800​

in case you need to know the conversion between AWGs and mm²;

 

[wattmatters]

in case you need to know the conversion between AWGs

Can anyone explain why I hear Americans say "ought" when referring to cable gauge, e.g. they say "one ought" or "double ought".

Ought to me means "anything" or "should", not zero.

If I wanted to indicate the wire gauge was 0, I would say "naught", as in "one naught" or "double naught".

Or is use of a silent "N" common in the US?

 

[12VoltInstalls]

Can anyone explain why I hear Americans say "ought" when referring to cable gauge, e.g. they say "one ought" or "double ought".

Ought to me means "anything" or "should", not zero.

If I wanted to indicate the wire gauge was 0, I would say "naught", as in "one naught" or "double naught".

Or is use of a silent "N" common in the US?

Colloquialisms pervert grammar

naught = never, nothing; pronoun
“with naught a concern” pre-modern pre-colonial english; 1200-1400ad

aught = zero; a digit; noun. Or: indiscriminate slight value above zero not defined by a fraction or whole number; “two aught cable” “double aught buckshot;” “seven aught miles from town, third farm on the left.” Colonial to modern english.

Aussie English was culturally suppressed from equivocal refinement of the ‘mother language’ (much like the USA was for different causations) by its history due to banishment of societally uncouth criminals and primary influence of rough seaman whose language was taught primarily by conversation not grammatical education. Those early 200? years essentially created an Aussie dialect that until modern times did not not have the continual influx of the broad range of English speakers that the North American continent had. Yet both English-speaking lands developed their own english style and neo-colloquialisms.

Aught is legacy english and can be used in three grammatically fluid manners. Naught is a grammatical departure even Shakespeare screwed up

Ought is a word the implies responsibility in something one should do, or is used to suggest a superior option to the initial intent of an individual.

 

[Zil]

Easy...
Wh is a capacity or usage unit with no confusion.

Ah is a calculation based on the voltage of the work being performed.

You wouldn't believe the number of times I've been asked how many Ah do I need to operate a 10A device...

No additional info.


So, is that 10A at 12V? 120V? 240? How long will the load be operating? What Voltage is the battery? Because all that is needed to give an answer in Ah...

In Wh the answer is easy...

How mamy Wh battery is required to operate a 300W appliance for 24h?

I selected your response by random selection just to reference my question.
So if I have this right, a Watt is not a calculated value. The Ampere is a calculated value? I have had that backwards my whole industrial life.
My foolish understanding had been, up to now that I'm enlightened, A battery supplies amperes into a circuit. A device demands watts to power that device. As the voltage drops as the battery drains, the watts the device demands atsys the same. Resulting in more amperes from the battery. As the battery by definition, has a limited number of amperes to supply. I should not use amp hours to measure battery capacity, available or remaining. And this is because Watt Hours is not a calculated value?

 

[Supervstech]

I selected your response by random selection just to reference my question.
So if I have this right, a Watt is not a calculated value. The Ampere is a calculated value? I have had that backwards my whole industrial life.
My foolish understanding had been, up to now that I'm enlightened, A battery supplies amperes into a circuit. A device demands watts to power that device. As the voltage drops as the battery drains, the watts the device demands atsys the same. Resulting in more amperes from the battery. As the battery by definition, has a limited number of amperes to supply. I should not use amp hours to measure battery capacity, available or remaining. And this is because Watt Hours is not a calculated value?

Sort of...

If you are on a forum asking how many amp hours you need to power a load for x hours...
We need to know the voltage of the battery and the voltage of the load to answer the question.
Also, the Ah rating of a battery is based on a specific load test. Usually 20A. Load, and batteries are more or less capable of supplying the Ah rate at different loads.

Wh is a calculation as well... heck, everything is a calculation... but if your load is in watts, and the battery is in watts, then it is a simpler question to answer what is needed if all the units are the same.

 

[Hedges]

Some abbreviations that have been stumping me.
Acronyms and Abbreviations has been LOCKED so I'm dumping them here. Maybe when there are enough of them the Mods will let svetz edit the thread.

You're welcome rmaddy.

@Hedges
SPDT and DPDT from this thread: Help me figure this out?

Single Pole Double Throw and Double Pole Double Throw.

That can apply to switches or relays.

After "Single" and "Double", use digits, like 3PDT



Of course, don't want to forget other common units like "peta", commonly heard when saying "petawatt laser"

Department of Energy gives green light for a flagship petawatt laser facility at SLAC

High-power lasers will work in concert with the lab’s X-ray laser to dramatically improve our understanding of matter in extreme conditions.

www6.slac.stanford.edu

Also "atto", as in "attosecond pulses"

Researchers manage to generate attosecond pulses at 100 kHz repetition rate

Attosecond laser pulses in the extreme ultraviolet (XUV) are a unique tool enabling the observation and control of electron dynamics in atoms, molecules, and solids. Most attosecond laser sources operate at a pulse repetition rate of 1 kHz (1,000 shots per second), which limits their usefulness...

phys.org

 

[Supervstech]

I selected your response by random selection just to reference my question.
So if I have this right, a Watt is not a calculated value. The Ampere is a calculated value? I have had that backwards my whole industrial life.
My foolish understanding had been, up to now that I'm enlightened, A battery supplies amperes into a circuit. A device demands watts to power that device. As the voltage drops as the battery drains, the watts the device demands atsys the same. Resulting in more amperes from the battery. As the battery by definition, has a limited number of amperes to supply. I should not use amp hours to measure battery capacity, available or remaining. And this is because Watt Hours is not a calculated value?

And exactly how do you get amps?

It is a watt load drawn at a certain voltage... the resulting calculation is amps...

So, your entire enlightened life you thought Amps were the base unit of power? I'm sorry, that must have been hard to cope with the world that way.

 

[Hedges]

An ampere is a coulomb per second, now conveniently assigned to the precise number 1/(1.602176634×10−19) = 10^19/1.602176634 elementary charges.

Coulomb - Wikipedia

en.wikipedia.org

A Watt is one Joule per second.

Watt - Wikipedia

en.wikipedia.org

 

[WYtreasure]

Let's keep in mind that this thread is not a general discussion of random acronyms. Please keep this thread related to the correct use of electrical units and misused abbreviations.

There is an acronyms page on this site. If you have a relevant DIY solar acronym to suggest then it should go that page:

Commonly used Forum Acronyms & Abbreviations

Solar is befuddling enough! Why use acronyms? Well, we're lazy typists.... :LOL: xSyP - e.g., 2S2P, shorthand for how many cells in Series (S) and Parallel (P). A - Amperes or amps. A measure of current. See warning. AC - Air Conditioning, sometimes A/C. AC - Alternating Current, a waveform...

diysolarforum.com

Thanks

The "Acronyms & Abbreviations" thread has been locked.

I am finding acronyms & abbreviations, within these forums, which I do not understand. I post & attempt to define them here so this thread can also be used as reference.

Cool, or not cool?