some questions. what charger? what are these holes?

[EVDRIVER]

Define power

Define energy

Please

It is defined above in my post.

 

[Slow1]

Define power

Define energy

Please

Read here: http://hyperphysics.phy-astr.gsu.edu/hbase/work.html" onclick="window.open(this.href);return false;

Pretty good primer. Key points to get:

Power denotes rate
Energy denotes capacity

Thus: Kw or w is a measure of "power" and kWh, Wh, joules are all measures of energy.

It really is that simple.

 

[nerys]

I agree with your definition ofnpower and energy

I think you have the kw terms backwards.

Of course i could be wrong. Documentation on your link to kw and kwh please.

 

[dgpcolorado]

I agree with your definition ofnpower and energy

I think you have the kw terms backwards.

Of course i could be wrong. Documentation on your link to kw and kwh please.

These things have been repeatedly defined correctly by other posters above. But here goes:

kWh: http://en.wikipedia.org/wiki/Kilowatt_hour" onclick="window.open(this.href);return false;

The kilowatt hour, or kilowatt-hour, (symbol kWh, kW·h, or kW h) is a unit of energy equal to 1,000 watt-hours, or 3.6 megajoules.

Note that it has nothing whatever to do with kW "per" hour. It is kilowatts "times" hours.


kW: http://en.wikipedia.org/wiki/Watt#Kilowatt" onclick="window.open(this.href);return false;

The kilowatt is equal to one thousand (10³) watts...This unit is typically used to express the output power of engines and the power of electric motors, tools, machines, and heaters...One kilowatt is approximately equal to 1.34 horsepower.

Like the engineers above, as a scientist I prefer to use my terms and abbreviations correctly to avoid confusion.

 

[nerys]

Ok watched some videos. it is clear I am incorrect.

I am correct in my results but incorrect in my terms and monikers.

what is strange is in the videos I watched which make it clear I am wrong I agree with everything in the video.

Very strange. I guess I am just using the wrong "terms" to describe the "right" things.

I still don't quite grasp "why" what I am using is wrong since I agree with everything they say. I am going to just have to do some learning on the terminology until I get it.

I was expecting to find a portion I did not agree with and go AHA that is why I am wrong but I agree with 100% of what they are saying.

Grrrr annoying. I will figure it out.

what is really annoying is that in the video they say 100 watt bulb on for 1 hour will use 100 watt hours of energy.

but they they say watt hours is not watts times hours

but to get 100w for 1 hours to be 100 watt hours you have to do watts times hours. watts PER hour

its a built in contradiction and I think that is what is aggravating me.

 

[Nubo]

Yes a watt is an amount of power. This is not hard stuff here.

A 1000watt bulb only consumes 1000watts if you run it for 1 hour.

This is not really rocket science. Lets say you want to solar offset you car. 20kw a day.

No. 20kWh a day

10 hours sunlight.

You dont need 3.3kwh. You need 2kwh.

No. You need 20kWh. Which means you need a system that will produce 20kWh during that 10 hours of sunlight. Since the solar production will vary over the course of that 10 hours, you will need a system with a peak output of considerably more than 2kW.

2kw per hour times 10 hours nets you 20kw total produce power.

More correctly, 2kw sustained for 10 hours would net you 20kwH. But solar doesn't work like that, as I pointed out above. This is an example of why it's important to know how these terms work. kW is an instantaneous rate. To plan and achive the desired output you need to plot that instantaneous rate over time, for various seasons, and integrate the areas under those curves. For example, what is the day's output for the system below, on Jan 1? The area under that blue curve represents kWH. Even though the peak output on Jan 1 is about 2kW, the total for that day is nowhere near 20kWh.

 

[nerys]

2kw per hour times 10 hours nets you 20kw total produce power.

More correctly, 2kw sustained for 10 hours would net you 20kwH.

there is no more correctly. you said PRECISELY the same thing just mixed up the words.

per hour times 10 hours IS EXACTLY THE SAME THING as 2kw sustained for 10 hours. there is NO difference at all in any way shape or form in those sentences as far as meaning is concerned.

SO maybe this is where I am confused.

I say 2+2=4

you say no more correctly 1+1+1+1=4

in my view we said EXACTLY the same thing.

why am I wrong why is your description "more" correct? (I am IGNORING the variability of solar it was just an example)

MIND you. I KNOW I am wrong. but knowing I am wrong means nothing to me. I need to understand "WHY" I am wrong or whats in my head is simply not going to change (which is why this is annoying

 

[Slow1]

2kw per hour times 10 hours nets you 20kw total produce power.
More correctly, 2kw sustained for 10 hours would net you 20kwH.

I would have said this as "2kW for 10 hours nets you 20kWh total produced power

there is no more correctly. you said PRECISELY the same thing just mixed up the words.

per hour times 10 hours IS EXACTLY THE SAME THING as 2kw sustained for 10 hours. there is NO difference at all in any way shape or form in those sentences as far as meaning is concerned.

The thing here is that "2kw per hour" really doesn't make sense. "kW" is already a rate, so it is redundant to say "per hour" and that is the hair being split here in the discussion. Sort of like saying "I'll drive 20mph per hour" - while perhaps you can say do that for 2 hours and you will go 40 miles and it isn't 'wrong', it is the expression of the idea with unnecessary words that makes it awkward to read/parse.

SO maybe this is where I am confused.

I say 2+2=4

you say no more correctly 1+1+1+1=4

in my view we said EXACTLY the same thing.

Agreed that the math is not in contention; rather it is the expression of the units that is leading to corrections/confusions.

why am I wrong why is your description "more" correct? (I am IGNORING the variability of solar it was just an example)

MIND you. I KNOW I am wrong. but knowing I am wrong means nothing to me. I need to understand "WHY" I am wrong or whats in my head is simply not going to change (which is why this is annoying

This discussion ran along the lines of understanding the terms "kW" and "kWh" and what they mean. So the quibble about saying "kW per hour" is that it doesn't display an understanding/acceptance that "kW" is a unit of rate that doesn't use/require a "per hour" (it really is a unit of joules per second if you want to really get down to it). So like you would never say "I drive 55mph per hour on the highway" it likewise makes no sense to say "My solar panels generate 6.5kW per hour" - it just makes no sense. You can say "My solar panels generated 6.5kW for a full hour" or perhaps to address Nubo's point that solar production isn't a constant rate one could say "My solar panels generated an average of 6.5kW for an hour" that would be meaningful.

I really appreciate the fact that you appear willing to try and understand this. It may seem to be subtle and immaterial, but in fact really grasping the meaning of these units may help you (and others) to understand other related concepts. Rampant misuse of the units/terms will likely lead to further confusion.

 

[Nubo]

2kw per hour times 10 hours nets you 20kw total produce power.

More correctly, 2kw sustained for 10 hours would net you 20kwH.

there is no more correctly. you said PRECISELY the same thing just mixed up the words.

First, please use quotes and/or learn how to use the quote system. It's hard enough to try to clear up the issue, without forcing readers to guess which parts of your post are yours and which are quotes of what other people have said.

We didn't say the same thing. The notion of "2kw per hour" is a misuse of the term. Watt is an instantaneous rate. As someone already noted, it ALREADY contains a "PER": 1 joule per second. It is nonsense to say "1 joule per second per hour". That actually is describing a situation where rate of consumption is CHANGING at the rate of 1 watt per hour -- this is definitely not what you meant to say.

...
MIND you. I KNOW I am wrong. but knowing I am wrong means nothing to me. I need to understand "WHY" I am wrong or whats in my head is simply not going to change (which is why this is annoying

I'll try to come up with an analogy that may trigger an "aha!" moment...

 

[jlv]

Please get your nomenclature correct. These are scientific units with specific abbreviations: watts is a capital W; kilowatts is kW, and kilowatt-hours is kWh. They have well defined meanings: http://www.rapidtables.com/electric/kWh.htm" onclick="window.open(this.href);return false;

A post with "w", "kw", or "kwh" indicates the person who wrote it probably doesn't know what they are talking about.

 

[Nubo]

Please get your nomenclature correct. These are scientific units with specific abbreviations: watts is a capital W; kilowatts is kW, and kilowatt-hours is kWh. They have well defined meanings: http://www.rapidtables.com/electric/kWh.htm" onclick="window.open(this.href);return false;

A post with "w", "kw", or "kwh" indicates the person who wrote it probably doesn't know what they are talking about.

Probably.

 

[jlv]

A post with "w", "kw", or "kwh" indicates the person who wrote it probably doesn't know what they are talking about.

Probably.

Or that they were too lazy to use the shift key. In which case, I doubt the accuracy of their post, since if they were lazy about that, I wonder how lazy they are with facts!

 

[Nubo]

A post with "w", "kw", or "kwh" indicates the person who wrote it probably doesn't know what they are talking about.

Probably.

Or that they were too lazy to use the shift key. In which case, I doubt the accuracy of their post, since if they were lazy about that, I wonder how lazy they are with facts!

And I wonder how people confuse a valid discussion about the importance (on an EV forum) of understanding some of the primary units involved with EVs, with simple pedantry. :roll:

 

[pncguy]

Should I even resurrect this thread? It is like they stopped making episodes of the Blacklist and I don't know who did it!

Did nerys ever "get it?"

 

[alanpozner]

Best way to cover those holes is with a license plate holder.

I beg to differ. See bumperplugs.com Search for Nissan

 

[nerys]

Thanks for the link. Very cool.

The price however. Holy crap $14 each! And i need 4

 

[QueenBee]

Best way to cover those holes is with a license plate holder.

I beg to differ. See bumperplugs.com Search for Nissan

I assume you actually haven't installed them on a LEAF since they'd look pretty silly since the 4 LEAF holes are all larger than 1/4".

"Fits vehicle bumpers with holes not exceeding 1/4" diameter."