Comments on: GM Advanced Battery Lab Tour w/Video – Part I

By: jeffhre

jeffhre — Thu, 02 Jul 2009 14:36:20 +0000

Examples: pcb’s in transformers, lead in gasoline. We eventually figured the total costs, due to unaccounted for externalities, were ultimately less if we just stopped using these seemingly cost expedient things.

By: Shaft

Shaft — Wed, 24 Jun 2009 05:04:01 +0000

Elon Musk wrote: “An important consideration that people without a technical background don’t understand is that you can either have a high power or a high energy cell chemistry, but not both.”

Why is that?

By: dorp7

dorp7 — Wed, 24 Jun 2009 00:33:04 +0000

I have to say, this was one of by best posts ever, on any chat board in my internet career. I still get a chuckle out of it, two days later, and apparently got a chuckle out of around 39 other folks too. Not only that, but the great Lyle himself replied, which is darn rare (he’s too busy living the electric dream as opposed to 99% of us posers). I didn’t think I could top the monkey thing from a couple months ago, but I did – and by a landslide. I’m awesome. Thanks for listening.

By: CaptJackSparrow

CaptJackSparrow — Tue, 23 Jun 2009 23:52:39 +0000

Take a look at the specs on this commodity cell: http://www.evcomponents.com/ProductDetails.asp?ProductCode=SE100AHA

It can handle a 4C 400A drain. The Volts cell (Manganese) can do much more than this cell due to it’s proprietary chemistry of LG. In the close future, commodity cells will be able to match current LG cells. There are other companies with even higher rate cells and there are companies with small very high power cells like this: http://www.all-battery.com/148volt8000mah15c-95ampstickstyle.aspx

So if you want to build a good batt pack for you DIY EV, the Skyenergy cells in the 120-160AH range will do you fine.

By: jeffhre

jeffhre — Tue, 23 Jun 2009 21:25:25 +0000

Lyle,
After the Cobasys incident it looks like your site has saved us from another terrible debacle! The future looks bright. Maybe bright is not the right word. It’s high amperage from here on!

By: Marcus R. (WL #5275)

Marcus R. (WL #5275) — Tue, 23 Jun 2009 17:44:10 +0000

Nice to know I can repurpose the battery for my submarine. Seriously, who’s trying to drown the thing?

By: Shaft

Shaft — Tue, 23 Jun 2009 16:21:13 +0000

OK, I’m understanding what C is. Thanks!

What I continue to be slightly incredulous about is that a single cell can support over 100 AMPS for a period of time … or at least that is what my calculation says. Is that really correct?

By: CaptJackSparrow

CaptJackSparrow — Tue, 23 Jun 2009 15:45:04 +0000

Remember the C rate is a divide by factor of time in Ah of the rated cell Ah or depending on the discharge rate a multiply factor.

Example: You have a 10Ah 3.5VDC cell. This means you can discharge the cell at 10A for 1 hr straight. This is 1C. Why it’s “C” I have no clue, I just follow the rules.

So let’s say you connect it to a motor that draw 15A. This means it draws 1.5 times more current (note the movement of the decimal point) so your C rate will be 1.5C. In realtion to time you can draw 15A you factor in 10Ah / 1.5C = .666hours

If you were to connect the 10Ah cell to a 20A motor, your C rate is 2.0C and again you plug in the number to get your rate of draw: 10Ah / 20A = .5hrs
So you see a pattern here? When you double your Ah drain yout cut the ability to drain for one hour in half.

Let’s say you connect a a 5A motor to it. Let’s plug in the equation: 10Ah / 5 = 2hrs
The pattern here is inversly proportional to the Drain Current > Ah rate where less current draw lengthens your time you can draw current.

By: GM Volt Fan

GM Volt Fan — Tue, 23 Jun 2009 13:03:49 +0000

Speaking of battery innovations …. it’s usually good news when the largest corporations get on the bandwagon in new technologies. This time its Big Blue. IBM is going to be doing some serious research on batteries. Specifically on “lithium-air batteries”. IBM and Intel are both leaders in nanotech that’s for sure. If anyone can use nanotech to create a huge battery breakthrough, it’s those guys.

http://www.businessweek.com/technology/content/jun2009/tc20090622_116016.htm?chan=top+news_top+news+index+-+temp_news+%2B+analysis

“On June 23, IBM announced a multiyear effort to increase the performance of rechargeable batteries by a factor of 10. The aim is to design batteries that will make it possible for electric vehicles to travel 300 to 500 miles on a single charge, up from 50 to 100 miles currently.”

The Japanese are working on the same lithium-air technology. America BADLY needs to be THE leader in energy storage technology or we’re going to miss the boat on “the next big thing”. Energy storage (batteries) will probably be bigger than the Internet was in the 90s.

By: benion2

benion2 — Tue, 23 Jun 2009 12:52:36 +0000

Captain Oldsmobile, Sen. from MA., will appreciate being able to submerge the batteries