Impress your friends by using correct units and abbreviations
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WYtreasure
It's not happy hour, I'm just like this.
CME: Coronal Mass Ejection
ICME: Interplanetary Coronal Mass Ejection
CME is a Sun Fart. ICME is a Sun Fart that reaches Earth. More appropriate definitions will influence edits of this post. ?
Some folks are forecasting more of these over the next few years.
Maybe we should consider preparing for these in our solar systems, maybe not. That is a discussion for another thread.
ICME: Interplanetary Coronal Mass Ejection
CME is a Sun Fart. ICME is a Sun Fart that reaches Earth. More appropriate definitions will influence edits of this post. ?
Some folks are forecasting more of these over the next few years.
Maybe we should consider preparing for these in our solar systems, maybe not. That is a discussion for another thread.
For anyone with an iPhone or iPad, hold down the zero key to get the option to enter the degree symbol. Super easy.
Strange. I’ve never seen that happen.
TerryTtibbs
New Member
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- Mar 15, 2022
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How many volts and how many currents is all I ever cared about, nothing else matters really.
This is my understanding. Storage Battery capacity is measured by Amp Hours. For deep cycle batteries, Standardized to 20 hours, but I have seen cheaters use 10 hours. It is the measurement of the amperes available and for how long. 100 a/h battery can discharge a steady 5 amperes for 20 hours then it's dead. Watts are a measure of work performed by the current.
And no one has mentioned the abbreviation " I " for current.
And no one has mentioned the abbreviation " I " for current.
wattmatters
Solar Wizard
Sorry to be pedantic but given this is a thread about correct use of terminology...
Watts are not a measure of work. Watts are a unit of power.
Work = energy = integral of power over time.
And power at any given moment = current x voltage.
For a battery, the Ah rating needs to be multiplied by the battery's voltage to provide an energy capacity value. It's this which determines how much work a battery is capable of doing.
The amount of work a battery is capable of performing is of course not a constant as you noted as it depends on the rate the battery is discharged amongst other factors (temperature, age, chemistry, variability of load etc).
TerryTtibbs
New Member
- Joined
- Mar 15, 2022
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- 56
Little V=tingle
Big V=wet your pants
Little A=feel a bit stiff
Big A=MR toasty
I suppose on this basis W=a combination of : - tingle, wet your pants, feel a bit stiff and MR toasty in various degrees.
Big V=wet your pants
Little A=feel a bit stiff
Big A=MR toasty
I suppose on this basis W=a combination of : - tingle, wet your pants, feel a bit stiff and MR toasty in various degrees.
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On the style guides saying to put a space between numbers and units-- I hate them. Nothing worse than trying to read a technical publication when you have a number and its units separated with a line break. I understand the argument for the space, but in practical terms it is bunk, especially when your unit is all lower-case.
Is there a common convention for things like kW(PV) on a device that cannot do subscripts?
Is there a common convention for things like kW(PV) on a device that cannot do subscripts?
Also
s - seconds
whereas
S - siemens, conductivity (1/ohms)
When I am peer-reviewing documents at work, many times I find myself writing up findings for the issues mentioned above.
Another is adding hyphens such as writing "milli-amperes" instead of milliamperes.
I agree with one of the reply of another user, that there should be a space between the value and its unit, such as using 25 ºC and not 25ºC, but I like how the lack of a space holds information together on one line if it would otherwise be split up by a carriage break, so I tend to let that one slide.
I believe the speed of light is c (lowercase).
While I don't personally like a space between a value and its abbreviated units for aesthetic reasons, the use of a non-break space eliminates the issue you mention. When typing a document in a word processor you should be able to enter a non-break space. On a Mac this can be done with option-space. Not sure about Windows, maybe Alt-space. In a web document you can use . A non-break space prevents the text on either side from being separated across lines.
Thanks for the reply, as I didn't know that was an option. I looked it up, and for MS-Word it is Ctrl-Shift-Space.
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.
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
Solar Wizard
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.
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
Solar Wizard
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
Mostly Harmless
- Joined
- Jan 6, 2021
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- 489
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
life passes by too quickly to not live in freedom
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.
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
It's not happy hour, I'm just like this.
300 x 24 = 7200
Warpspeed
Solar Wizard
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.
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
It's not happy hour, I'm just like this.
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? ?
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? ?
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:
diysolarforum.com
Thanks
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
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