HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Comments
View Comments: Newest First|Oldest First|Threaded View
<<  <  Page 2/2
Cadman-LT
User Rank
Platinum
Re: Comparison with gasoline
Cadman-LT   10/14/2012 8:01:16 PM
NO RATINGS
You guys make good points. I never stopped to think about the weight of the gas compared to the weight of the batteries before. Makes total sense.

naperlou
User Rank
Blogger
Re: Comparison with gasoline
naperlou   10/13/2012 11:50:39 AM
NO RATINGS
Chuck, that's a good point.  I like to let my car run down to empty, if I am in an area with lot's of gas stations, becuase it will get slightly better mileage toward the end of the tank.  Another thing to note is the difference weight of the engines.  I don't know what the Tesla S engine weighs, but I was told that the Tesla Roadster engine weighs only 70 lbs.  Add to that the fact that there is no transmission, and the S engine has to weigh a lot less than the 550i engine. 

One thing this makes clear is that when comparing two very different technology systems one has to consider more than the core part of the system.  In this case the motors are vastly different and just comparing them would leave you to believe that the electric car should be lighter.  Add in the energy storage system, and you come up with a very different story.

Nice new picture, by the way, but they cut off the top of your head. 

Charles Murray
User Rank
Blogger
Re: Comparison with gasoline
Charles Murray   10/12/2012 6:25:00 PM
NO RATINGS
You're right, Naperlou. You are essentially saying that the specific energy of gasoline is far higher than that of a lithium-ion battery. And, yes, that's a drawback. It's also a drawback when the battery's charge is depleted. The 900 lb battery still weighs the same. It still has to carry its own dead weight, whereas the weight of the gasoline in your example has gone from 73 lbs to zero when the gas tank is depleted.

naperlou
User Rank
Blogger
Comparison with gasoline
naperlou   10/12/2012 10:35:01 AM
NO RATINGS
Cap'n, I read this article with interest.  While doing so I looked up a number of things.  What I found was suprising.  One comment you made was the search for a $5K battery pack that got 300 miles of range.  Tha is a long way off, as you mention. 

With a gasoline engine at 23 mpg (see below), the 300 mile range translates to 13.04 gallons.  The weight of the gasoline is 72.88 lbs.  Tesla claims that range for their Tesla S with the 85 kW-h battery.  The weight seems to be about what the roadster's is at a minimum.  That would be 900 lbs.  The ICE gets 0.26 lbs./mile, while the Tesla S has a rating of 3 lbs./mile.  So, the first thing that needs to be addressed is the weight of the battery.  The Tesla S battery has density of 94.44 W-h/lb.  This is at the high end of the range you quote for current batteries (note the unit difference). 

What is even more interesting is that the curb weight for a Tesla S is 4,647.3 lbs.  That's a lot.  The roughly equivalent BMW 5 series sedan (which Tesla is targeting with the S) is the 550i sedan.  The power output is similar, The BMW weighs 4,365 lbs.  I find this very interesting for both given all the articles and discussion on weight saving, etc. that the car manufacturers are supposedly working on. 

 

<<  <  Page 2/2


Partner Zone
Latest Analysis
Here's a variety of views into the complex production processes at Santa's factory. Happy Holidays!
The Beam Store from Suitable Technologies is managed by remote workers from places as diverse as New York and Sydney, Australia. Employees attend to store visitors through Beam Smart Presence Systems (SPSs) from the company. The systems combine mobility and video conferencing and allow people to communicate directly from a remote location via a screen as well as move around as if they are actually in the room.
Thanks to 3D printing, some custom-made prosthetic limbs, and a Lego set, one lucky dog and a tortoise has learned new tricks.
An MIT research team has invented what they see as a solution to the need for biodegradable 3D-printable materials made from something besides petroleum-based sources: a water-based robotic additive extrusion method that makes objects from biodegradable hydrogel composites.
With Radio Shack on the ropes, let's take a memory trip through the highlights of Radio Shack products.
More:Blogs|News
Design News Webinar Series
12/11/2014 8:00 a.m. California / 11:00 a.m. New York
12/10/2014 8:00 a.m. California / 11:00 a.m. New York
11/19/2014 11:00 a.m. California / 2:00 p.m. New York
11/6/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  67


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service