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!

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.

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.