Wednesday, March 28, 2007

Blogs Are Everywhere

Today we introduce a new evolution of the Tesla Motors corporate blog. As you can see, we have now gone from one blog to four “channels.” In addition, we will move away from posting predictably every Wednesday (well, almost) to a more fluid schedule. You might also see some more variation between blogs that are [...]

The EV Experience

Stephen Casner spent 25 years working on protocols and systems for transmission of audio and video over packet networks, starting before the Internet existed and continuing through the Internet Multicast Backbone (MBONE). He was recruited to the Silicon Valley to work with startup Precept Software and its IP/TV product, which was later acquired by Cisco. [...]

Thursday, March 22, 2007

Tesla Roadster Progress – From EP to VP

We’ve just achieved a significant milestone on our road to Tesla Roadster production. Our first Validation Prototype was assembled at the Hethel facility in the U.K. and was recently airlifted to our San Carlos, Calif., workshop to commence system testing.

VP1 at the Hethel, U.K., facility. The car is riding
a little high because the battery pack [...]

Monday, March 12, 2007

My Mental Health and Lithium.

Whether your an occasional lurker of the EVlist archives or a frequent visitor of the Green Car Congress, you find out pretty quickly about the latest (public) movements in battery technology. Without any doubt, lithium technology is forging ahead, things are moving really fast. Early last year A123 Systems signed a deal with the large [...]

http://www.electric-echo.com/blog/?p=38

My Mental Health and Lithium.

Whether your an occasional lurker of the EVlist archives or a frequent visitor of the Green Car Congress, you find out pretty quickly about the latest (public) movements in battery technology.
Without any doubt, lithium technology is forging ahead, things are moving really fast. Early last year A123 Systems signed a deal with the large battery manufacturing company China Bak Battery to make lithium battery packs primarily for DeWalt (Black and Decker) power tools. These Nano-Phophate Li-ion batteries have some very promising spec’s (mainly the number of recharge cycles) AND they’re cheaper to make AND mass production is making them even cheaper.
DeWalt 36V Li-on Battery Pack
Then a few weeks ago there was a discussion over at GCC on the economics of these batteries and how they’re not far off a tipping point of affordability. Believe it or not the proposition was put that if a new 36V DeWalt battery pack reached the price of $40 on eBay then lithium would be unstoppable and could compete with fossil fuels as an economic energy storage medium! So what’s the current eBay price? Only about $130. I don’t know about you but I find this very exciting…

Last year I requested a quote from Kokam batteries for a lithium battery pack for the E-E. Their customer service was exceptional and their price tempted me then, yet it was twice this price per kWh AND they have a much less life AND much lower maximum charge and discharge rates.
So then a couple of weeks ago I started dreaming about these DeWalt packs and how to get inside them (and so was regular commenter Carl!) and look what Google turns up; somebody’s written an article about just that! This is an awesome website that goes into a lot of detail about these A123 batteries, these RC (radio control) geeks know their stuff and the only thing unproven to them is life expectancy.
DeWalt opened up
So I take a sniff around the A123 Systems website again and low and behold they’re selling “Developer Kits” for their M1 batteries. Now at $20 per cell you’d be better off buying a DeWalt pack and wrecking it ($16/cell) but I’m sure they’d give a discount for 1500 cells! Wouldn’t they??
Yep, that’s right, one thousand five hundred batteries. Here’s the figuring;

  • I need a 10kWh battery pack for a 30km range (that’s in a real car in the real world, people).
  • Each cell is 2.2Ah by 3.3V which equals 7.5Wh.
  • 10,000 divided by 7.5 = 1,300 cells.
  • Add a few more because you can’t have too much Lithium = 1,500.

I would clump 33 of these batteries in parallel giving a massive maximum constant current draw of 2,300 Amps! I would then join 45 of these clumps end on end to get the required voltage (approx 144V). Technically this battery pack could deliver enough current to run four E-E motors at the same time AND be re-charged again in minutes!
Ok…so I’ve sent an email off to the folks at A123 Systems requesting a quotation and I’ve filled in one of their customer enquiry forms. I hope they’re as enthusiastic about loopy EV amateurs as the Kokam folks were…

Wednesday, March 7, 2007

The Media Need to Toughen Up on the Subject of EVs

I’ve been reading Michael Schnayerson’s book, The Car That Could, about the inside story on the development of General Motor’s EV1. It’s a fascinating read and I recommend it to anyone interested in the history of modern electric vehicle development. I had the good fortune of meeting the author during my first week at Tesla [...]