LeftieBiker
Moderator
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Delivery Date: 30 Apr 2018
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Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 1:01 am

LeafSpy Pro + Konnwei KW902 ELM327 BT OBDII dongle
Isn't that the BAD OBDII dongle...?
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

cwerdna
Posts: 9833
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 1:24 am

LeftieBiker wrote:
Mon Aug 26, 2019 1:01 am
LeafSpy Pro + Konnwei KW902 ELM327 BT OBDII dongle
Isn't that the BAD OBDII dongle...?
Yes. Of that model, some of them are bad. Some aren't. The ones that are bad can be fixed.

'19 Bolt Premier
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

LeftieBiker
Moderator
Posts: 13498
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 3:47 am

cwerdna wrote:
Mon Aug 26, 2019 1:24 am
LeftieBiker wrote:
Mon Aug 26, 2019 1:01 am
LeafSpy Pro + Konnwei KW902 ELM327 BT OBDII dongle
Isn't that the BAD OBDII dongle...?
Yes. Of that model, some of them are bad. Some aren't. The ones that are bad can be fixed.
It may not be a good idea to advertise them in a signature line, though. Better to promote the ones that work 100%, and trash your CANBUS 0% of the time...
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

SageBrush
Posts: 4907
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 4:26 am

A lot of the confusion seems to come from laziness, and no small amount of arrogance that ignorance should be tolerated. Irony that.

As to *why* people have difficulty, I think it comes from trying to match the pattern of gallons, and gallons per time. This is why it is common to see kW/h: the presumption is that gallons are to kW as gallons/h are to kW/h. My wife and I have discussed this more times than I care to count. She understands that one of the units is an amount and the other unit is amount per time ... yet her mind refuses to accept that a rate is not written as something *per time.*
It does no good to write for her
(amount/time)*time, or to explain to her that the watt unit is a ratio by definition. She accepts the algebra as correct but cannot translate the meaning into everyday usage.
She finds her inability to use the units easily VERY frustrating. In her case it is not from lack of effort.

The Australians use the mega-Joule instead of the kWh to denote an energy amount. They lose some calculation convenience but I suspect have less confusion in the units.
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

css28
Posts: 50
Joined: Fri Aug 02, 2019 2:14 pm
Delivery Date: 02 Aug 2019
Location: Bloomfield Twp, Michigan

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 5:16 am

SageBrush,
I think you've touched on the root of the confusion.
Most "rate units" have time in the denominator (miles/hr, km/hr, ft/sec) and kW just feels wrong to people who aren't interested in analyzing it.

If megajoules were the currency of choice I suspect people would be far more comfortable with it. Example; My battery holds 108 MJ when fully charged. My car consumes 14.8 MJ/hr when I'm traveling at 60 mph.

P.S.: You're a gm-volt forum alumnus, right? Tdiclub as well?
- Chris
----------
2017 SV, purchased 8/10/19, Coulis red

Flyct
Posts: 271
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Leaf Number: 307113
Location: Bradenton, Florida, US

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 6:20 am

To add to the confusion about units of measurement and which is TRULY correct.

There are countries that use the the metric system and then there is the country that went to the moon.

Flame suit on.
2019 Leaf SL Plus w/All Options
2015 Lexus RX450h Hybrid SUV
2019 Ford F-350 Lariat Ultimate Crew Cab Short Bed Diesel
2017 Grand Design Reflection 337RLS 5th Wheel RV
2017 Kawasaki FXT-Pro LE Side by Side
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css28
Posts: 50
Joined: Fri Aug 02, 2019 2:14 pm
Delivery Date: 02 Aug 2019
Location: Bloomfield Twp, Michigan

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 6:40 am

Flyct wrote:
Mon Aug 26, 2019 6:20 am
To add to the confusion about units of measurement and which is TRULY correct.

There are countries that use the the metric system and then there is the country that went to the moon.

Flame suit on.
Fortunately, the subject of this rant is all SI units. It would be worse if we were characterizing things in Btu and horsepower.
- Chris
----------
2017 SV, purchased 8/10/19, Coulis red

SageBrush
Posts: 4907
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 7:14 am

css28 wrote:
Mon Aug 26, 2019 5:16 am
P.S.: You're a gm-volt forum alumnus, right? Tdiclub as well?
I have posted in both those forums in the past.
Many would have been happy if I had not. Just like here :lol:

I wasted a lot of time on those forums but one person actually corrected some confusion on my part about COP and explained the thermodynamic basis. I'm indebted to that person. It might actually have been you.
Last edited by SageBrush on Mon Aug 26, 2019 7:40 am, edited 1 time in total.
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
Posts: 4907
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 7:22 am

css28 wrote:
Mon Aug 26, 2019 6:40 am
It would be worse if we were characterizing things in Btu and horsepower.
I get nauseated just hearing those units.

I'm always amused by home heating and cooling conventions in Btu. The actual unit being measured is Btu/hour.
Somewhere along the line the industry bowed to ignorance.
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
Posts: 4907
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Why do we still confuse KW and KWH?

Mon Aug 26, 2019 8:23 am

Flyct wrote:
Mon Aug 26, 2019 6:20 am
To add to the confusion about units of measurement and which is TRULY correct.
There are countries that use the the metric system and then there is the country that went to the moon.
The imperial system is correct, that is not the point. The point is that it is cumbersome.
As for your presumption, it is wrong. Electrical engineering went metric before I was born. I'm less sure about rocketry engineering but physics went metric long ago.
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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