# Tesla Model S Charging Question



## EVEngineeer (Apr 11, 2012)

If I was to charge a 60kw model S with a standard outlet aka nema 5-15, how long would it take to charge from empty to full?

The chart says 5 miles per hour, but the interactive chart is showing different, unless I did something wrong. 
I found this info. http://www.teslamotors.com/charging#/outlet


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## frodus (Apr 12, 2008)

It's 60kWh, not 60kW.

And it depends on what you get out of the charging cord... lets say 1500W comes into the Tesla from the wall.

60kwh / 1.5kW = 40 hours


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## EVEngineeer (Apr 11, 2012)

frodus said:


> It's 60kWh, not 60kW.
> 
> And it depends on what you get out of the charging cord... lets say 1500W comes into the Tesla from the wall.
> 
> 60kwh / 1.5kW = 40 hours


lol rlly ? "It's 60kWh, not 60kW." 
40 is what I was thinking too. just wanted to make sure, because that's a long time.


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## Siwastaja (Aug 1, 2012)

EVEngineeer said:


> lol rlly ? "It's 60kWh, not 60kW."


Yes, really. If you did use a few minutes of your life to study the first basics of electronics to understand the concepts of power and energy, you would have directly "seen" the answer to your own question. That understanding would also become handy if you wanted to do some EV engineeering one day! 

That being said, it is not unusual on this forum not to understand _anything_ about electricity and still build electric cars.

The usual teaching style and material also isn't very helpful. You should start the learning the concept in this order: first energy, then power, and after these are thoroughly understood with a lot of examples, then maybe go to voltage, resistance and current which need to be taught together at the same time.

It is apparent on this forum that a lot of people have been told about "volts" and "amps" but not about "watts" let alone "watt-hours", which is a very misleading unit for beginners; Joule would so much better in understanding the concept.


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## onegreenev (May 18, 2012)

Well there are loads of folks who want an EV and only want one to Drive. They don't want one and have to be an EE to get there. They just want to drive and enjoy. It is quite possible and it is up to you who are EE's to understand that and help them get there. Also to instruct them on the generally little they need to maintain the vehicle and keep it operational. I am in that field. I just want to have fun. I don't want to go get a masters degree in electronics first. 

Thankfully you don't need all that to get your car on the road and to enjoy it and to have it for a very long time. 

Pete


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## Duncan (Dec 8, 2008)

Siwastaja said:


> "watt-hours", which is a very misleading unit for beginners; Joule would so much better in understanding the concept.


Hallelujah!!

watt-hours should be Joules (3,600 of them)
Amp-hours should be Coulombs (3,600 also) 

Using the correct name helps a LOT in understanding what is going on!

To OneGreen's point - you do not need to be an EE (I'm not) BUT you do need to have a basic understanding - and it's not that hard


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## kennybobby (Aug 10, 2012)

*How So?*



Duncan said:


> watt-hours should be Joules (3,600 of them)
> Amp-hours should be Coulombs (3,600 also)
> 
> Using the correct name helps a LOT in understanding what is going on!


<rant mode on>
All we have done is changed the measurement units from the names of two old dead famous scientists, to the names of two different old dead famous scientists--so how does that help in understanding?

It seems to me that folks may intuitively understand the basic concepts of the metric system of units such as meters, kilograms, seconds, and charge, but then get lost in the jumble of non-intuitive units called out after the names of a bunch of old dead (rip) guys:
Ampere
Coulomb
Henry
Ohm
Volta
Watt
Faraday
Tesla
Gauss
Newton
Siemens
Kelvin
etc...

To give something a special name doesn't really define what it is unless it is tied to an understanding of the basic first principles, and even then that can be a stretch.

If someone is trained in the sciences, then the units will become part of his vocabulary, but that doesn't necessarily mean for example, that he will have a practical working knowledge of how to hook up a scope to measure these units...
</rant off>


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## Siwastaja (Aug 1, 2012)

*Re: How So?*



kennybobby said:


> <rant mode on>
> All we have done is changed the measurement units from the names of two old dead famous scientists, to the names of two different old dead famous scientists--so how does that help in understanding?


You totally missed the point -- it is that Wh and Ah are "derived units" with integrated multiplication which is hard to grasp, especially as they are derived _in the wrong order_.

Let me explain with a direct analogy.

You have a _distance_, for example, in kilometers or miles. Then you have _time_, in hours. Both very easy to grasp. You can derive speed, which will be_ km/h _or _mi/h_. Very intuitive.

Similarly, you have _energy_, for example, energy to boil one liter of water, or energy to travel one kilometer. Again, you have time. The rate you use the energy would be energy per time. This would be intuitive. The units would be, for example, joules per second, but could be anything else. They need to be named after something, but there would be just one dead-scientist name so far (the energy unit).

The problem is not in the names, it's that a _derived_ unit (J/s) which would be intuitive _as is_, is _RENAMED_ after another dead scientist without real reason (no need for separate "watt", as we don't need separate name for km/h), and to further drive the situation crazy, then the BASIC unit (energy) is back-annotated from the renamed derived unit (which gives us Wh). You need to do the math on the unit equation to understand what's going on!

Wh is analogous to renaming mi/h, let's say, Kennybobby, and then calling any distance that previously was 100 miles, 100 Kennybobby-hours. And we have an unit with "hour" in it, and you have to understand all the math and background to understand that time has _absolutely nothing_ to do with it. Just like watt-hours have absolutely nothing to do with hours.

(There is a speed unit with a specialized name, knot, but they didn't go that far as renaming distances as knot-hours.)



---

Amp-hour isn't that bad because you need to understand all the shit anyway if you want to understand it; but in principle, it has exactly the same problem; Coulomb is not the unnecessary "extra" unit; Ampere is!

But things such as distance, time, temperature, ENERGY, etc. should be common knowledge taught in schools in a first few years. Energy is super-duper important. Still it is totally missed or complicated using two different units so that people even don't recognize Wh as a unit of ENERGY.

But now we are in a situation where people kind-of-think-they-understand Amps and Volts, but have difficulties with Watts (no wonder; an obfuscated renamed unit) and are totally incapable of understanding Watt-hours (absolutely no wonder). This is just the opposite order it should be. First is energy. Volts, amps, ohms, etc. only provide details how this energy is "constructed".


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## EVEngineeer (Apr 11, 2012)

What the crap happened to this forum? I ask one question, because I wanted to make sure that I had the correct answer. The next thing I know I'm getting sarcastic remarks, and a lesson in things from a few different classes that I have taken. I just like to have my answers proofread, I do not like to continue a problem until I have my answers looked over. The question that I asked was so minuscule to the full picture of what I am doing. To be honest if you ask me what the full picture is, I probably couldn't even tell you though, because I have many questions that I never hear an exact answer for and because of my personality, I listen to other's for answers, but I like to test things out myself and do my own math. It's not that I don't trust people, I am more confidant with seeing it written out myself. 
Thanks for reading.


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## Siwastaja (Aug 1, 2012)

EVEngineeer said:


> What the crap happened to this forum? I ask one question, because I wanted to make sure that I had the correct answer.


This is a discussion forum, not your personal helpdesk. I think you should be happy that your simple question (which BTW was already answered!) raised some serious discussion, but if you only want a simple answer, please just stop reading after you get it!

I can, however, guarantee you that your projects will fail if you just want numerical answers without understanding your own question nor the answer. This is a common source of engineering mistakes. Engineers love numbers over anything.

In a way, I think people like me are grateful to your seemingly simple questions which however do open a possibility for a much broader discussion because the question shows a very deep-level problem, not in you or your question, but in the basic science and education.

Your nickname and the "oh rlly" answer actually ignited my replies. "EV Engineer" should know energy and power!


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## subcooledheatpump (Mar 5, 2012)

EVEngineer, I'm not actually sure how much you know, so here is a crash course. It might seem like an insignificant proofreading mistake, but it's the most important aspect of an electric vehicle, that is, how much energy you actually have. 

To say I have an electric car with 60 kW isn't such a big deal, that's only 80 HP. That's important to know, because it will tell you about the cars performance, but what's more important is for how long you will have that power. Which is energy. 

Watt-Hours, or Thousand Watt-Hours (kWh) is a measurement of how much energy the battery can hold. 

This may not be totally accurate, but just to give you an idea, if I have a 1 kWh battery, then I can extract 60 kW continuously for 1/60 of an hour. 

But then if I have a 60 kWh battery (without any losses or internal resistance) I should be able to extract 60 kW continuously for 1 hour. 

Sorry if you already knew this, since it isn't well understood, maybe some others can benefit from it


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## sabahtom (Mar 1, 2011)

*some equations are more equal than others*

Thanks for taking the time to write that out, it's very helpful for newbies like myself when the knowledgeable guys have a discussion about stuff that's always taken for granted. I'm teaching basic science to high school students and they often struggle with this, because the course starts at ohm's law and does a year of that before getting to energy.


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## Duncan (Dec 8, 2008)

Hi Siwastasa

_The problem is not in the names, it's that a derived unit (J/s) which would be intuitive as is, is RENAMED after another dead scientist without real reason (no need for separate "watt", 
_*Disagree with this bit Joules are energy - watts are power - it is appropriate to have separate names**Just as it is appropriate to have Amperes for electron flow and Coulombs for charge
*_
as we don't need separate name for km/h), and to further drive the situation crazy, then the BASIC unit (energy) is back-annotated from the renamed derived unit (which gives us Wh). You need to do the math on the unit equation to understand what's going on!_

The problem is that we already have a name for this "thing" - it's energy called Joules

Watt hours is redundant and misleading it is an energy measure with the name for power - totally misleading


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## Siwastaja (Aug 1, 2012)

Duncan said:


> Watt hours is redundant and misleading it is an energy measure with the name for power - totally misleading


Yea, you can think it that way too. Plus, it also has name for TIME in it, which is similarly misleading. Power has to do with time; energy does not. Energy is like food, and power is how quickly you eat it. The latter has the concept of time in it.

This is why I suggest that if one of them is going to be a "derived" unit (unit without a name of its own, but based on other units), it should be power. Power is how much energy is used in a certain time, or how _quickly_ energy is used; how _quickly_ things are heated, etc.; we humans tend to think as a function of time.

Having a separate name can become handy, but OTOH we have absolutely no problems in talking about "speed limit of 50 miles per hour" or "maximum speed: 200 km/h" in our daily communication. Having fewer names makes things easier as long as the derived units are similar to our everyday logic and do not have too many units in them (I think maximum is two.) Division in units ("per") is easy to grasp, especially when the divider is time, but somehow multiplication is not.


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## WarpedOne (Jun 26, 2009)

> What the crap happened to this forum?


Nothing, it is a forum. When you ask a stupid question, you get all sort of answers.

You asked about 60 kW Model S ... there are only 225, 270 and 310 kW versions. Where did you find a 60 kW one? Who sells it? Who makes it?

How long does it take to charge each of them? 
Depends on what you set as being 'full' and how far you have driven after the car said it was empty.

Go read up on EVs, you are still full of misconceptions.


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## EVEngineeer (Apr 11, 2012)

WarpedOne said:


> Nothing, it is a forum. When you ask a stupid question, you get all sort of answers.
> 
> You asked about 60 kW Model S ... there are only 225, 270 and 310 kW versions. Where did you find a 60 kW one? Who sells it? Who makes it?
> 
> ...


Everyone is taking me so damn literally...........I didn't mean forum, I meant thread. This one question that I asked, I already knew the damn answer, but I'll say it again, I wanted to make sure I did the math correct. 

http://www.teslamotors.com/models/options I think you may be mistaken, it says at the top 60 and 85 kwh.


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## WarpedOne (Jun 26, 2009)

We are taking you literally because there are 60 kW ICE vehicles out there. Many of them. How long it takes to charge them?

You still don't see your mistake.


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## EVfun (Mar 14, 2010)

Duncan said:


> The problem is that we already have a name for this "thing" - it's energy called Joules
> 
> Watt hours is redundant and misleading it is an energy measure with the name for power - totally misleading


Electricity is sold in the USA by the kWh, kilowatt hour. We buy cells rated in amp hours and use them to build a battery pack at the voltage of our choice. Multiply those together and you get watt hours. Sure, I can multiply that by 3600 to get Joules, but why? I'm going to have to divide by 3600 again to figure out how much it will cost to charge the pack.


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## major (Apr 4, 2008)

EVEngineeer said:


> If I was to charge a 60kw model S ....





EVEngineeer said:


> .....it says at the top 60 and 85 kwh.


The basic problem is not the units, but those who think energy and power are the same things. 

That's just my opinion based on years of observation and irritation with it. Often those using incorrect units will write it off as trivial or typographical, but usually the problem is deep seeded.


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## Siwastaja (Aug 1, 2012)

EVfun said:


> Electricity is sold in the USA by the kWh, kilowatt hour. We buy cells rated in amp hours and use them to build a battery pack at the voltage of our choice. Multiply those together and you get watt hours. Sure, I can multiply that by 3600 to get Joules, but why? I'm going to have to divide by 3600 again to figure out how much it will cost to charge the pack.


Of course it's simple once you understand it. Most do not. I consider it _should be_ common knowledge so that it would be taught at schools. When people used horses to move around, they did understand that a horse needs to eat a certain amount of certain stuff and so on. Now people know that an electric car needs "electricity" which is exactly correct, but when it comes to any more details than that, let alone quantities, they shun away because the math simply doesn't seem to make any sense. Even though in reality it is as simple as horses eating hay. Or, gasoline car using x liters to go 100 kilometers, or go x miles with one gallon.

Joule and Coulomb indeed are not handy because one second is very short time. That doesn't change the principle. Everything would be crystal clear if Watt was originally an alternative unit for energy (3600 Joules); and then power would be W/h. In fact many people seem to use the units exactly like this!

I have tried to explain watts and watt-hours to my parents many times but it just doesn't cut through. It's not only them. Heck, if DIY electric car builders don't understand it, how could laymen?

So my point in a nutshell: non-ridiculous units would help to understand the difference of the _concepts_ of energy and power, even if the units wouldn't matter in the end.


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## major (Apr 4, 2008)

Siwastaja said:


> Joule and Coulomb indeed are not handy because one second is very short time.


But the Joule or Coulomb has nothing to do with time. You said so yourself. 



Siwastaja said:


> Power has to do with time; energy does not.


And EVfun pays for his electrical energy in units of kWh, not Wh, so he could just as easily pay for MJ or GJ


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## Siwastaja (Aug 1, 2012)

Good point .

But once you factor in time to get "power", you would usually (although not always!) want to use a bit longer time unit than a second, and then, it's handy to be able to do this without the constant multiplier of 3600. 1000 is easy. Therefore it's nice to have "direct" compatibility between the units. This is similar to having electron-volts as an alternative unit. eV is not a problem however as the only people who use this unit know what they are doing so they know it has nothing to do with voltage.

Well, if time was divided so that hour had, say, 1000 seconds, we wouldn't have this problem either! 

It's natural to divide the year into 365 days, but it's pure madness to divide it into 24 parts then 60 then 60. "hour", "minute" and "second" have no physical meanings.

But this is the historical payload, just like imperial units.


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## evmetro (Apr 9, 2012)

Evengineer, I knew immediately what you meant when you referred to 60kw. The electrical engineers will slap you around a little, but hang in there. They rough me up sometimes, but they have also taught me A LOT in the process. There is a communication barrier that exists between them and the typical diy guy, but they are getting better, as you can see where frodus was able to see outside the EE box and was able to identify what you were asking about. 
I am one of those guys who builds EVs without enough knowledge of the principles of electricity, but I am learning. I saw some really nice guidelines in this thread about what to study and in what order. I am on it...


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## EVEngineeer (Apr 11, 2012)

evmetro said:


> Evengineer, I knew immediately what you meant when you referred to 60kw. The electrical engineers will slap you around a little, but hang in there. They rough me up sometimes, but they have also taught me A LOT in the process. There is a communication barrier that exists between them and the typical diy guy, but they are getting better, as you can see where frodus was able to see outside the EE box and was able to identify what you were asking about.
> I am one of those guys who builds EVs without enough knowledge of the principles of electricity, but I am learning. I saw some really nice guidelines in this thread about what to study and in what order. I am on it...


Thanks I appreciate your comments.


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## frodus (Apr 12, 2008)

Wow.....I think I'm the only one in this whole f*cking thread that actually answered the original question. The rest is just whining and moaning about units.

From the nature of the rest of the posts, I think We ALL knew what he meant.... I think we can stop now. He gets it.


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## JRoque (Mar 9, 2010)

Hi all. IMHO, a simple "I think you meant kWh" would have sufficed but so would have "thanks for the correction". Many posts, including this one of mine, are not contributing much to the OP's topic.

Cheers,
JR


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## Siwastaja (Aug 1, 2012)

frodus said:


> Wow.....I think I'm the only one in this whole f*cking thread that actually answered the original question. The rest is just whining and moaning about units.
> 
> From the nature of the rest of the posts, I think We ALL knew what he meant.... I think we can stop now. He gets it.


OH WOW indeed! Isn't it SURPRISING you were the only [first] one who answered the question? I think we all should have repeated the answer:

40 hours!

40 hours!

40 hours!

40 hours!

after you, to make a VERY interesting discussion.

Or of course, not saying anything to discuss science is always a good choice on DIYElectricCar.

This forum indeed is full of stupid people .

Oh I'm so sorry I am so harsh on the internets.

And to everyone concerned;

You get harsh words sometimes, live with it. Try to learn from it. Ignore it if you can't; it's your loss. Don't make a show out of your own stupidity and inability to accept direct speech. Look, the world does not turn around your ego; we may want to discuss science, education etc., just _inspired_ by the original post. And if we can turn a "SUP DAWG HOW MUCH IS 1+1?" "HeY its TWO" discussion into anything else, I'm positive that having it gone offtopic is not any kind of loss.

Anyone know any EV related forum where intellectual discussion and saying things out straight is encouraged (or at least tolerated), instead of stupidness, politically correct fudging or staying silent?


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