smkettner
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Re: Why do we still confuse KW and KWH?

Tue Aug 27, 2019 11:11 am

cwerdna wrote:
Mon Aug 26, 2019 11:12 pm
smkettner wrote:
Mon Aug 26, 2019 10:00 pm
No one is actually confused.
...
Simple slip of the keyboard makes way too big a deal of it. For those that are always careful and deliberate to get this right perfectly every time I commend you. For the rest... let it go.
Sometimes, it's not a slip of the keyboard. Sometimes, a person keeps getting it wrong over and over. This guy is an example: http://mynissanleaf.com/viewtopic.php?p=389319#p389319. He was not just making typos. He didn't know what he was talking about. Read his further replies in that thread like
" A 40w light bulb is not 40w (that would mean it burns out after 1hr) its a 40 wh light bulb"
" A 3000w genny is actually a 3000wh genny"
"a 40w bulb is not 40watts. that would mean the bulb can only work for 1 hour. your average "cheap" incandescent 40w bulb is actually a 60,000w bulb (40watts times estimated lifespan of 1500 hours)

the RATE it consumes power is 40 watts per hour." UGH!

How about Reeler that I referred to at viewtopic.php?p=564743#p564743? What's surprising and scary is his background and "experience" with EVs: viewtopic.php?p=565245#p565245.

There are a few folks who fairly often get it wrong, say 50% of the time, not 80 to 100% of the time. For them, I think it's a lack of understanding and not a slip up either.
Yes the out of context corrections make a mess of things. I contend neither was confused.
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Flyct
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Re: Why do we still confuse KW and KWH?

Tue Aug 27, 2019 1:05 pm

EVDRIVER wrote:
Tue Aug 27, 2019 7:20 am
Let's not even start on 110/220V.

There you go. It’s 120/240v NOT 110/220v. (This is good for another 5 pages of responses)
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SageBrush
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Re: Why do we still confuse KW and KWH?

Tue Aug 27, 2019 1:45 pm

Flyct wrote:
Tue Aug 27, 2019 1:05 pm
EVDRIVER wrote:
Tue Aug 27, 2019 7:20 am
Let's not even start on 110/220V.
There you go. It’s 120/240v NOT 110/220v. (This is good for another 5 pages of responses)
That was his point ;)
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SageBrush
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Re: Why do we still confuse KW and KWH?

Tue Aug 27, 2019 1:48 pm

smkettner wrote:
Tue Aug 27, 2019 11:11 am
Yes the out of context corrections make a mess of things. I contend neither was confused.
Whatever.

How about this: take the time to try and write clearly, or if needed, take the time to LEARN. Otherwise do not expect people to take the time to answer.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

SageBrush
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Re: Why do we still confuse KW and KWH?

Tue Aug 27, 2019 2:47 pm

alozzy wrote:
Mon Aug 26, 2019 12:12 am
There are so many misconceptions and misunderstandings about all kinds of things, so confusion over kW vs kWh is relatively forgivable in my opinion.

I'm a lot more worried that some people still think that the earth is flat, or that there is zero gravity in space, or that the sun is actually yellow, or that science is a collection of irrefutable facts and so any "mistakes" that past scientists made, which are later refuted, somehow utterly disproves all scientific understanding and achievement (detractors of the theory of evolution love that argument).
Unfortunately but not surprisingly, the people who most aggressively think they should be able to write incorrect units without comment are also the most scientifically ignorant and much more often than not, AGW denialists.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

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Nubo
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Re: Why do we still confuse KW and KWH?

Tue Aug 27, 2019 11:55 pm

EVDRIVER wrote:
Tue Aug 27, 2019 7:20 am
Let's not even start on 110/220V.
Bit of a tangent, I noticed recently that our home voltage was gradually dropping over a week or so (reading from a small UPS). We're normally close to 125V. I ruled out internal wiring and figured something with the transformer or substation was overstressed from warm weather demands.

When it got down to 110V I contacted the utility. I was surprised but they actually came and checked. They confirmed that it was upstream somewhere and needed further investigation. Next day, unplanned 3000 home outage that they had to dispatch a crew. But afterwards we were back over 120V.
I noticed you're still working with polymers.

goldbrick
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Re: Why do we still confuse KW and KWH?

Wed Aug 28, 2019 9:59 am

Line voltage certainly varies with demand until it hits a brownout (low voltage) or blackout. One thing that is dependable is that the frequency is always very close to 60.0 Hz. I'd bet there are regulations on both the allowable voltage level range and frequency range but the frequency is controlled to a much tighter spec.

With the advent of smart meters I wonder if the system will become more closed loop. Ie, will the various meters report feed back the voltage at that point so the network/grid can make adjustments to even out voltage variations. AFAIK, without smart meters the grid is very open-loop with the only feedback/controls at the substation levels. Or maybe there are monitoring stations placed around the grid that report back somehow.

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Nubo
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Re: Why do we still confuse KW and KWH?

Wed Aug 28, 2019 12:07 pm

goldbrick wrote:
Wed Aug 28, 2019 9:59 am
Line voltage certainly varies with demand until it hits a brownout (low voltage) or blackout. One thing that is dependable is that the frequency is always very close to 60.0 Hz. I'd bet there are regulations on both the allowable voltage level range and frequency range but the frequency is controlled to a much tighter spec.

With the advent of smart meters I wonder if the system will become more closed loop. Ie, will the various meters report feed back the voltage at that point so the network/grid can make adjustments to even out voltage variations. AFAIK, without smart meters the grid is very open-loop with the only feedback/controls at the substation levels. Or maybe there are monitoring stations placed around the grid that report back somehow.
I suspect they do have automated alerts, but the voltage was still within allowable limits. What probably wasn't being watched was the trend. After seeing it creep down day after day I was like "shit's about to go down, dawg". :lol:
I noticed you're still working with polymers.

jjeff
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Re: Why do we still confuse KW and KWH?

Thu Aug 29, 2019 3:47 am

Common N. American voltages that I've seen:
120v- can sometimes drop down a bit but the term 110v is really outdated AFAIK.
208v-Commercial 3 phase 240v, can drop down close to 200v. Uses (2) 120v commercial legs.
220v-like 110v it's an outdated term AFAIK.
240v-generally residential power using (2) 120v legs.
277v-commercial 3 phase power using just 1 hot, not really used for EVs except some Teslas.
480v-commercial 3 phase power using (2) 277v legs, probably only used for QC DC stations but in this case they'd probably use all (3) 277v hots.

I believe some locations use lesser voltages than 480v for internal power and in that case I don't know if they use less than 277v/hot, I've only seen 277/480v in my line of work, I'm sure true electricians have see more types than me.

And AFA the whole KW and kWh, I'm personally one that gets confused on it frequently and often refer to old posts to get it right, same as the spelling for their, there, they're, I've been told many times what is correct and even looked it up but for some reason it's really hard for me to get it correct :? but I try :)
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JayCan
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Re: Why do we still confuse KW and KWH?

Thu Aug 29, 2019 4:30 am

Nubo wrote:
Tue Aug 27, 2019 11:55 pm
EVDRIVER wrote:
Tue Aug 27, 2019 7:20 am
Let's not even start on 110/220V.
Bit of a tangent, I noticed recently that our home voltage was gradually dropping over a week or so (reading from a small UPS). We're normally close to 125V. I ruled out internal wiring and figured something with the transformer or substation was overstressed from warm weather demands.

When it got down to 110V I contacted the utility. I was surprised but they actually came and checked. They confirmed that it was upstream somewhere and needed further investigation. Next day, unplanned 3000 home outage that they had to dispatch a crew. But afterwards we were back over 120V.
Power authorities have a 10% plus/minus tolerance for output supply. At 110v still acceptable but barely. Summer is the worst time for voltage drop issues due to heavy AC loads. Since there was a power outage shortly after probably one transformer of a 3 phase array in a substation yard was degraded and causing the drop in voltage. It probably tanked, dropping out that part of the grid.
'15 SL 40k kms, 12 bars

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