Sunday, May 31, 2009

Whoops!

I had another one of those 'marvel at the power of electricity' moments this weekend...

On a leisurely Sunday drive, the power suddenly cut out on me, never a good thing. Luckily I was at a place near home where I could pull over, call for a quick tow, and all was good. After I got back home, I started checking voltages. I thought at first a fuse has gone out again, but I was wrong - waaaay wrong.

One of my battery posts had melted to about half its original size. Check it...
After being amazed at the melted post for awhile, I started working a theory of why it happened. Most likely a loose connection, coupled with high current draw, equals arc, and further deterioriation, which leads to further arcs, more heat, and MELTING!

The reason I think this happened was because I am using non-flexible cable, and during motion of the car, these connections between batteries, no matter how tightly they're cinched down, will come loose with the vibration of these battery boulders.

The battery in question seems okay voltage-wise. I will be looking into getting the post repaired, and also looking into replacing some of the more at-risk cables with their flexible alternatives.

Live and learn!

Tuesday, May 12, 2009

Price analysis on Lithium Batteries


I found this site:
http://ehsmanager.blogspot.com/2009/04/happy-9th-birthday-lithium-ion-battery.html

and the following experience curve on Li-Ion batteries...


I would probably jump in at the $400/KWh point on the curve. For the type of batteries I am looking for in Electro, that would run me $6000.

Saturday, May 9, 2009

Enter Electric Hellfire

Well, Electro took me about a year of evenings and weekends to complete. Electric Hellfire took me exactly one. This kit, from GoldenMotor.com, took a couple of hours to fit to Matt's mountain bike. Here is a pic:



The motor is very subtle - a larger than usual hub on the front wheel. Everything fit perfectly, and although no instructions came with the kit, the PDF from the website and the color-coding of the wires and connectors helped make this assembly a cakewalk. Here is a picture of the controls:


Cruise control and horn on the left, thumb throttle on the right. The kit came with brake controls that hook into the normal brake cables. The only difference with these is that the brakes also are wired into the controller to signal stopping cruise control if it's on.

The installation components are very well manufactured. The wheel went on with no issues (albeit minor brake caliper tuning, which you would do with any new wheel), and the battery box fit easily as well. The only downside to this kit was the motor controller, which arrived with no enclosure. I didn't have an electrical enclosure this narrow to house it, so I made due with some tupperware for now.

The first test ride went flawlessly. Hellfire goes FAST. At full throttle, it can approach 25-30MPH on the flats. It takes hills easily, although super steep hills are still an issue - the draconian hill in our neighborhood was the acid test, and Hellfire made it 3/4 of the way up before conceding. Note: this was while taking Big Daddy up the hill - Matt made it to the top just fine!

I'll try getting a video or two of riding Hellfire posted soon. I also want to test range of the lithium pack.

Tuesday, April 28, 2009

New EV project looming for the summer: E-Bike!

I am interested in eventually replacing my lead-acid battery pack with a LiFePO4 pack, which will decrease weight, increase range and speed, all that good stuff. But since LiFePO4 batteries are much more pricey and are managed differently, I thought I'd start with a smaller EV project that uses them, to better understand how they perform.

Enter the E-Bike project!

I bought a donor bike off of craigslist, and have just ordered a DIY E-Bike conversion kit from goldenmotor.com in China. The kit contains a 36V/750W hub motor, 36V10Ah LiFePO4 battery pack, motor controller, throttle, wiring, etc. Should be here in about three weeks. Can't wait!

Sunday, April 19, 2009

Lessons learned #347: LRR Tires

OK, EV fans. If anyone ever tells you that Low Rolling Resistance (LRR) tires are one of the key pieces to your vehicles energy efficiency, LISTEN TO THEM.

I recently bought a used set of low profile tires off of craigslist that made Electro look supercool and be very energy inefficient. Let me explain.

The stock tires for Electro were 185/60/14, which translates into tires that are 185mm wide and go on 14in wheels.

The new "supercool" wheels/tires I bought were 205/40/16s, which means they were 205mm wide, low profile, and had extra big wheels (16in).

Driving the same distance with the wider tires made a HUGE difference in the amount of energy I was using, which is extremely important in an EV. For a trip where I would normally use 7.1 KWh, I ended up using 9.3 KWh. That's 30% more energy - to look cool.

I am going back to stock wheels/tires for now until I can go the other way and find a narrower set of LRR wheels and tires. Hopefully I will find some that will get me significant range increases!

Monday, March 23, 2009

Electric motorcycle dragster video

Check out this lightning bolt. Power band? We don't need no stinkin' power band!

http://www.youtube.com/watch?v=eNkJCdEEzpM

Saturday, March 21, 2009

Ford's new electric debuting in 2011

Designed and built almost entirely by an outside supplier - in Canada!

http://money.cnn.com/2009/03/20/autos/ford_electric/index.htm?postversion=2009032005

Another article about Better Place, an electric car infrastructure company. They're all about replacing gas stations with charge stations.

http://www.cbsnews.com/stories/2009/03/16/sunday/main4869332.shtml