Go Back   EcoModder Forum > EcoModding > Fossil Fuel Free
Register Now
 Register Now
 


Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 09-20-2009, 11:31 PM   #1 (permalink)
Lurker is indeed accurate
 
Join Date: May 2009
Location: ATL
Posts: 23
Thanks: 0
Thanked 7 Times in 1 Post
Electric cars and Power inverters

Random topic number 4:

In this electric car I'm trying to brain storm thru I'll need AC power for the occasional accessory. Specifically a laptop in my case. In my present GAS car I plug my little inverter into the cigarette lighter, and I get AC enough to run/charge the laptop. This is heavily dependent on the inverter. A brief search turns up inverters up to 3000 watts.

Clearly the devices I've seen mentioned to step down to 12V would work. I'll need one for the cigarette lighter. But am I wasting energy doing that? Would some other method of getting AC be more efficient?

I had assumed I'd be creating a DC vehicle but I'd certainly like to hear about AC motor options too as I'm trying to educate myself.

Perhaps I'm over-complicating things.

-Russ

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 09-21-2009, 12:21 AM   #2 (permalink)
Master EcoModder
 
Join Date: Sep 2008
Location: Texas
Posts: 632
Thanks: 0
Thanked 25 Times in 23 Posts
If the pack voltage range is between about 140 and 370, you can just use the existing laptop power supply.
PriUPS update 08 Jan 2006
__________________
If America manages to eliminate obesity, we would save as much fuel as if every American were to stop driving for three days every year. To be slender like Tiffany Yep is to be a real hypermiler...

Allie Moore and I have a combined carbon footprint much smaller than that of one average American...
  Reply With Quote
Old 09-21-2009, 01:08 AM   #3 (permalink)
Master EcoModder
 
Ryland's Avatar
 
Join Date: Jan 2008
Location: Western Wisconsin
Posts: 3,903

honda cb125 - '74 Honda CB 125 S1
90 day: 79.71 mpg (US)

green wedge - '81 Commuter Vehicles Inc. Commuti-Car

Blue VX - '93 Honda Civic VX
Thanks: 867
Thanked 433 Times in 353 Posts
every time you add a step you get a loss, a/c motors tend to be more efficient because all motors in the end run off a/c, with a d/c motor it is being mechanically changed to a/c as the motor rotates, this is the job that the carbon brushes have, sad thing is carbon is not very conductive but it is used because it is self lubricating and wears well without welding it's self to to commutator or creating many other problems.
With an a/c brush less motor you do away with the brushes... of course and rely on the switching of the a/c, because the motor has to vary in speed you need an inverter that is designed for this, if you want to run a regular 120v motor in your electric car and run it off a/c it is going to get more complex and less efficient, granted I only described a few of the many options but if really, you just want to run your lap top off an electric car, get a d/c to d/c converter and a 12 volt cord for your lap top, it is basically going to be a switching power supply, pretty efficient.
  Reply With Quote
Old 09-21-2009, 01:47 AM   #4 (permalink)
Master EcoModder
 
Join Date: Sep 2008
Location: Texas
Posts: 632
Thanks: 0
Thanked 25 Times in 23 Posts
If the pack voltage is between about 140 and 370, the existing laptop power supply will work as the DC/DC converter. And if it's a recent one, it will also be surprisingly efficient.

Just make sure to set cpufreq or whatever to use power saving even on external power. Power management is often limited on external power in order to increase performance. In particular, it takes a short time for the PMS* (Power Management System) to sense the increased load and a little more time for the PLL to adjust.

*PMS has been referred to as "power management stress" due to the annoyance of the clock adjustment lag. My solution is to use a KDE applet (PowerDevil or something like that) to manually change the power management setting. It defaults to aggressive power saving on battery, normal power saving on external power, and I can manually force full CPU speed when I need it.

__________________
If America manages to eliminate obesity, we would save as much fuel as if every American were to stop driving for three days every year. To be slender like Tiffany Yep is to be a real hypermiler...

Allie Moore and I have a combined carbon footprint much smaller than that of one average American...
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Converting power steering to electric power steering Daox EcoModding Central 54 01-17-2017 07:16 PM
Electric car conversion: Project ForkenSwift MetroMPG Fossil Fuel Free 1041 07-28-2014 10:19 AM
Can I use a GENERATOR to power an Electric car directly? Nerys Fossil Fuel Free 128 10-01-2012 02:24 AM
New CVT transmission electric-assist with electric assist Ptero Fossil Fuel Free 2 09-23-2010 11:41 PM
Itís a Trend! 3 Dirt Cheap DIY Electric Cars SVOboy EcoModder Blog Discussion 6 03-18-2009 09:40 AM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com