How to tell a kilowatt hour from a kelvin week henry

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Paul9
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Re: How to tell a kilowatt hour from a kelvin week henry

Post by Paul9 »

Thanks coulomb when writing my post I suspected I was "out" by a factor of a coupla billion!

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Re: How to tell a kilowatt hour from a kelvin week henry

Post by EVdownUnder »

Did anyone read the RACV article on "Dictionary of energy jargon – and how to decode it."

https://www.racv.com.au/royalauto/livin ... coded.html
KwH.JPG
KwH.JPG (17.84 KiB) Viewed 374 times

"Get fluent in the language of gas and electricity with this handy energy lingo decoder."

Well done RACV. I thought it would make me laugh but I actually started crying :cry:
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Re: How to tell a kilowatt hour from a kelvin week henry

Post by weber »

Wow. Thanks for that, Patrick. They could hardly have got it any wronger. If you're an RACV member, it would be good to email them about it. I'm sure they don't want to be wrong any longer than they have to. At least they got megajoules right. :)
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Re: How to tell a kilowatt hour from a kelvin week henry

Post by smithy2167 »

They appear to have made a correction. It now says kWH ... nearly there!

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Re: How to tell a kilowatt hour from a kelvin week henry

Post by EVdownUnder »

weber wrote:
Mon, 23 Dec 2019, 11:22
Wow. Thanks for that, Patrick. They could hardly have got it any wronger. If you're an RACV member, it would be good to email them about it. I'm sure they don't want to be wrong any longer than they have to. At least they got megajoules right. :)
I emailed them the same day I posted here, and cheekily asked for a year of free subscription for my editing work :lol:
I'm still waiting for a reply :roll:
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Re: How to tell a kilowatt hour from a kelvin week henry

Post by weber »

Here's another fine point of symbol usage that relates specifically to batteries.

The relative rate of charge or discharge of a battery is often described as a multiple of its capacity, by using the letter "C". For example a "2C" charge or discharge of a battery with a capacity of 100 amp hours, corresponds to a current of 200 amps.

In this case, the letter "C" is not a unit symbol but a quantity symbol. In other words, it's a variable. It stands for "capacity", as in C = 100 Ah. So "2C" is intended to mean: multiply the capacity figure in amp hours by 2 and treat it as a current in amps. The dropping of the "h" for hours is understood.

We should not put a space of any kind between the 2 and the "C", because that would mean 2 coulombs, a measure of charge, not current. A coulomb is an amp second.

But even without the space, it could still be read as coulombs. The standard way to distinguish quantity symbols from unit symbols is to set quantity symbols in italics. So the correct form is 2C .

To ease the pain of typing this, I use yet another compose-key sequence with the free software for Windows called WinCompose, so I only need to type Right Alt c space .

<Multi_key> <c> <space>		: "[i]C[/i] "	# BBCode italic C, SPACE, for capacity (a quantity, not a unit)

Here are a bunch of other compose-key sequences I use to save keystrokes when typing units, including not having to use the shift key in most cases.

# SI Unit and multiplier symbols preceded by a narrow no-break space
<Multi_key> <space> <0>		: " °"	U202F U0080 # NARROW NO-BREAK SPACE, DEGREE SIGN
<Multi_key> <space> <a>		: " A"	U202F A # NARROW NO-BREAK SPACE, A for ampere
<Multi_key> <space> <A>		: " A"	U202F A # NARROW NO-BREAK SPACE, A for ampere
<Multi_key> <space> <c>		: " °C"	U202F U0080 C # NARROW NO-BREAK SPACE, °C for degree Celsius
<Multi_key> <space> <C>		: " C"	U202F C # NARROW NO-BREAK SPACE, C for coulomb
<Multi_key> <space> <F>		: " F"	U202F F # NARROW NO-BREAK SPACE, F for farad
<Multi_key> <space> <g>		: " g"	U202F g # NARROW NO-BREAK SPACE, g for gram
<Multi_key> <space> <G>		: " G"	U202F G # NARROW NO-BREAK SPACE, G for giga
<Multi_key> <space> <h>		: " h"	U202F h # NARROW NO-BREAK SPACE, h for hour
<Multi_key> <space> <j>		: " J"	U202F J # NARROW NO-BREAK SPACE, J for joule
<Multi_key> <space> <J>		: " J"	U202F J # NARROW NO-BREAK SPACE, J for joule
<Multi_key> <space> <k>		: " k"	U202F k # NARROW NO-BREAK SPACE, k for kilo
<Multi_key> <space> <K>		: " K"	U202F K # NARROW NO-BREAK SPACE, K for kelvin
<Multi_key> <space> <l>		: " L"	U202F L # NARROW NO-BREAK SPACE, L for litre
<Multi_key> <space> <L>		: " L"	U202F L # NARROW NO-BREAK SPACE, L for litre
<Multi_key> <space> <m>		: " m"	U202F m # NARROW NO-BREAK SPACE, m for milli and metre
<Multi_key> <space> <M>		: " M"	U202F M # NARROW NO-BREAK SPACE, M for mega
<Multi_key> <space> <n>		: " n"	U202F n # NARROW NO-BREAK SPACE, n for nano
<Multi_key> <space> <p>		: " p"	U202F p # NARROW NO-BREAK SPACE, p for pico
<Multi_key> <space> <P>		: " P"	U202F P # NARROW NO-BREAK SPACE, P for peta and pascal
<Multi_key> <space> <r>		: " r"	U202F r # NARROW NO-BREAK SPACE, r for revolution
<Multi_key> <space> <R>		: " Ω"	U202F Ω # NARROW NO-BREAK SPACE, Ω for ohm
<Multi_key> <space> <s>		: " s"	U202F s # NARROW NO-BREAK SPACE, s for second
<Multi_key> <space> <S>		: " S"	U202F S # NARROW NO-BREAK SPACE, S for siemens
<Multi_key> <space> <t>		: " t"	U202F t # NARROW NO-BREAK SPACE, t for tonne
<Multi_key> <space> <T>		: " T"	U202F T # NARROW NO-BREAK SPACE, T for tera
<Multi_key> <space> <u>		: " µ"	U202F µ # NARROW NO-BREAK SPACE, µ for micro
<Multi_key> <space> <v>		: " V"	U202F V # NARROW NO-BREAK SPACE, V for volt
<Multi_key> <space> <V>		: " V"	U202F V # NARROW NO-BREAK SPACE, V for volt
<Multi_key> <space> <w>		: " W"	U202F W # NARROW NO-BREAK SPACE, W for watt and weber
<Multi_key> <space> <W>		: " W"	U202F W # NARROW NO-BREAK SPACE, W for watt and weber
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).

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