kWh vs kW and why it's important

[mbender]

I disagree. It's pedantic when people complain about which letters of kWh are capitalized. But the difference between kilowatts and kilowatt hours is fundamental to conversations about electric vehicles.

An extra 3kw would be amazing in the leaf.

Just to be clear, I understood that the author thinks "an extra 3kW would be amazing" because maybe the sluggish acceleration would improve. At no time did I make the connection that he meant and additional 3kWh battery capacity.
So the author's assumption that everyone understood what he meant is not accurate.

He just likes being an ass.

The author should consider to try to understand the topic instead of name calling someone who uses units of measurements correctly.

adding an apostrophe to "EV" to make it plural (let alone adding an apostrophe to verbs).

+1+1+1 ... = +10

EVSE vs. charger is another conversation altogether, and I'm all for precise use of language. But EVSE is the silliest, most awkward-sounding acronym ever created! Well, maybe the acronym isn't that bad, but insisting that it be used in place of the plug one uses to charge an EV, rather than 'charger' is pedantic at best. Almost anywhere EVSE is used -- if and when expanded into its full four words (and/or spoken) -- would make those sentences sound absurd, pretentious and/or ungrammatical.

{ it's its / there their / even no know now and others } I can overlook because people type fast and the frequency of those words in writing is fairly close. I agree that many do not know or appreciate the difference(s) between 'affect' vs. 'effect' though, and there's simply no good excuse for mixing up the "to"s!

My 2¢ and humble, unsolicited, opinion.

 

[GRA]

snip>
EVSE vs. charger is another conversation altogether, and I'm all for precise use of language. But EVSE is the silliest, most awkward-sounding acronym ever created! Well, maybe the acronym isn't that bad, but insisting that it be used in place of the plug one uses to charge an EV, rather than 'charger' is pedantic at best. Almost anywhere EVSE is used -- if and when expanded into its full four words (and/or spoken) -- would make those sentences sound absurd, pretentious and/or ungrammatical.

I try to use charging station when I'm writing or speaking to a general audience, and keep EVSE for we tech nerds. But I occasionally slip up and write 'charger'.

{ it's its / there their / even no know now and others } I can overlook because people type fast and the frequency of those words in writing is fairly close.

Yeah, I let those slide, because when I'm typing fast I often use their instead of there or they're, even though I know the difference. Being seriously anal I go back and correct them when I notice them.

I agree that many do not know or appreciate the difference(s) between 'affect' vs. 'effect' though, and there's simply no good excuse for mixing up the "to"s!

My 2¢ and humble, unsolicited, opinion.

I agree with your comment and hope it will have the appropriate effect, while not appearing to be an affectation.

 

[Nekota]

The units can get even more interesting. Miles per gallon is actually convertible to mm^2. Think of it a little more literally, and it makes sense.

It only makes sense if you think there's such a thing as 2-dimensional gasoline. :lol:

It makes sense to me since a gallon is volume measurement and a mile is a linear distance. Divide volume by distance and you get an area. Or sweep area for a distance to make a volume. Now for numbers - 1 gallon (US) is 3.78 10^6 mm^3 and a mile is 1.609 10^6 mm. Dividing a gallon by a mile results in 2.35 mm^2. Now stretch that area to 30 miles long and it shrinks to 0.078 mm^2. To convert to a tube diameter multiply by 4/pi and take square root - resulting in 0.0993 mm or rounded to 10 um . A hair from your head is 60-80 micron for comparison.

Another way to think of this is the gasoline required to power a car getting 30 miles from a gallon of gas is being injected into the engine as a stream that is 10 millionths of a meter in diameter.

Now I think I did the math right - anyone want to check?

<edit>

I made a mistake ! (Thanks Alan) I took .078 mm^2 and converted to microns or 78. Then 4/PI gives 99 and square root is just shy of 10. But the correct answer is 315!

 

[LeftieBiker]

I try to use charging station when I'm writing or speaking to a general audience, and keep EVSE for we tech nerds. But I occasionally slip up and write 'charger'.

The best term I've come up with, in terms of ease of use and accuracy combined, is "charging cable" or even "charge cable."

 

[dgpcolorado]

I try to use charging station when I'm writing or speaking to a general audience, and keep EVSE for we tech nerds. But I occasionally slip up and write 'charger'.

My solution for that one is to use "charge station", which is both accurate and easy to understand. Yes, EVSE is awkward.

Yeah, I let those slide, because when I'm typing fast I often use their instead of there or they're, even though I know the difference. being seriously anal I go back and correct them when I notice them.

I both notice and appreciate those who use the correct words and spelling, as well as those who take the time to edit out typos. There are some people here at MNL who write beautifully and with clarity; some others, not so much.

The online posting mistake that seems most common to me, and really grates, is using "your" for "you're". I don't really understand why homophones are so difficult for so many. Perhaps they aren't taught in schools anymore.

 

[GRA]

I try to use charging station when I'm writing or speaking to a general audience, and keep EVSE for we tech nerds. But I occasionally slip up and write 'charger'.

My solution for that one is to use "charge station", which is both accurate and easy to understand. Yes, EVSE is awkward.

Yeah, I let those slide, because when I'm typing fast I often use their instead of there or they're, even though I know the difference. being seriously anal I go back and correct them when I notice them.

I both notice and appreciate those who use the correct words and spelling, as well as those who take the time to edit out typos.

I've now gone back and capitalized 'being'. :lol: As the sweatshirt a friend bought for me some years back reads, "Does anal retentive have a hyphen?" We either already know the answer, or will go crazy until we find out!

There are some people here at MNL who write beautifully and with clarity; some others, not so much.

Well, that excludes me. I consider my writing style to embody all the worst elements of a lawyer crossed with an engineer, even though I'm neither. Clauses, sub-clauses and sub-subclauses wrapped in parentheses inside of brackets, as all the exceptions to the general statement occur to me (and MUST be listed), and excessive technical detail until most people's eyes glaze over (but _I_ would find it essential for full understanding, and have trouble realizing that everyone doesn't desire that level of detail). I have gotten slightly better at tailoring my explanations for the audience, but I have to work at it.

At least I usually avoid excessive use of jargon and acronyms, unless I know my audience is conversant with them. I remember one aviation-related forum where we got so tired of one guy's stringing of technical acronyms together like so many railroad cars hauling coal, prefaced and suffixed by some pithy phrases that only the real grognards could decipher, that we started aping his style back at him to get him to stop. Cruel, but it needed to be done. Even though most of us could work out his meaning eventually, and what he said was usually valuable, it took more energy to unscramble his style than it was worth. First we tried gentle hints, but when that didn't work we had to resort to sterner measures.

The online posting mistake that seems most common to me, and really grates, is using "your" for "you're". I don't really understand why homophones are so difficult for so many. Perhaps they aren't taught in schools anymore.

I don't know if they're still taught. I was shocked to find some years ago that geography no longer is taught in K-12. Actually, considering how clueless many Americans are about the world's geography, as used to be shown when Jay Leno was asking questions of people on the street ("On what continent is Israel?" "China?"), I suppose I shouldn't have been so surprised.

But homophones are difficult, because of the way our brains perceive words, phrases and sentences when we read. There used to be a little test circulating around, where you were asked to read a paragraph and count how many times the letter 'f' appeared, upper or lower case. How hard could it be? I've been a heavy reader since I was a child as well as an excellent speller, and figured I would ace it. To my surprise, I missed by quite a lot. Here's a shorter version - read it as you normally would and count them:

Finished files are the re-
sult of years of scientific
study combined with the
experience of many years.

 

[mctom987]

…adding an apostrophe to "EV" to make it plural. It's just "EVs" dammit...

My EV's green. *grin*

 

[alanlarson]

The amazing thing I found was a sign next to a NRG Evgo charge station in Milpitas the other day:

Please note:
Level 2 charger
is delivering
a charge at
approximately
3.3 kW/hour.
This charger is
scheduled for
replacement

So, they annoy the folks who are pedantic about EVSE vs charger, they got my attention by not getting the units
right.

I tried to figure what kW/hour was, and I only could come up with a rate of change of power. So after 2 hours,
it would be delivering 6.6 kW . . . It doesn't make real-world sense, but that is what you get when you refer
to things with the wrong units.

But then, this is next to a DC quick charger that is sitting in front of a No Parking space, hashed off so one
is not supposed to park there even for charging.

 

[Nubo]

The units can get even more interesting. Miles per gallon is actually convertible to mm^2. Think of it a little more literally, and it makes sense.

It only makes sense if you think there's such a thing as 2-dimensional gasoline. :lol:

It makes sense to me since a gallon is volume measurement and a mile is a linear distance. Divide volume by distance and you get an area. Or sweep area for a distance to make a volume. Now for numbers - 1 gallon (US) is 3.78 10^6 mm^3 and a mile is 1.609 10^6 mm. Dividing a gallon by a mile results in 2.35 mm^2. Now stretch that area to 30 miles long and it shrinks to 0.078 mm^2. To convert to a tube diameter multiply by 4/pi and take square root - resulting in 0.0993 mm or rounded to 10 um . A hair from your head is 60-80 micron for comparison.

Another way to think of this is the gasoline required to power a car getting 30 miles from a gallon of gas is being injected into the engine as a stream that is 10 millionths of a meter in diameter.

Now I think I did the math right - anyone want to check?

<edit>

I made a mistake ! (Thanks Alan) I took .078 mm^2 and converted to microns or 78. Then 4/PI gives 99 and square root is just shy of 10. But the correct answer is 315!

Thanks for bringing me back to 3-D gas.