Jan 2010 update, part 1

I drove the Twike more almost all of my driving in July and August (>800 miles on the odometer now). Unfortunately, very hot temperatures (>104F), some long drives (>15 miles), and some other circumstances resulted in several of the old Ni Cad cells shorting out (death for a Ni Cad). Thus my two 12-13 year old packs were unbalanced and would not charge correctly anymore. With the start of school in September, I parked the Twike while I resumed driving my gas car and plotted the repairs. My first attempt was to charge and discharge all the 20 cell groups to locate the bad boys (which I did) and to attempt to fix them. The easiest way is to charge/discharge candidate groups of cells and measure the capacity of some other packs to locate a candidate group of cells. I was able to do this after a month or two of testing. I replaced one group with the new group but the BMS in this battery failed to come up in the car after I placed it back in the car. Not clear why. In frustration, I swore to give up on trying to use the old Ni Cad cells and move on to my A123 M1 lithium cells. To that end, I finished the design of the pack and over the Christmas holidays, I drew up the design for the new battery packs. I went over to Tap Plastics (right at the start of a big snow storm) and picked up parts needed to build them. Two days of construction and the new packs are done. The picture above is a test fit of the two new battery packs (just the plastic boxes) into the car with the old batteries removed. Fits perfectly with not even a 1/16 inch to spare. I like the very secure fit into the old battery wells. I using ABS plastic. I went with 3/16 rather than 1/4 because I want to maximize cell area. I hope this is strong enough to survive heavy bumps with the cells inside. I'm now into heavy battery pack construction. My goal is an exact replacement for the old packs but with LiFePO4 cells (A123 M1 cells). I'm planning on a 112s5p configuration with the 2.3Ah cells which works out to 4.24KWH pack and a range of 50 to 60 miles (assuming 60WH/mile).

My Twike meets its first Tesla

Today was the OEVA EV Awareness day in Portland, Oregon. We had vehicles of many types from conversions, to factory production vehicles, to motorized bikes. I was there all day with my Twike since I can now drive from my house to downtown and back and I'm also part of the OEVA group. What made my day though was when a Tesla showed up. The owner is David Stiers who you may remember as the actor who played Charles Winchester on MASH! It turns out his is retired and lives just south of Newport Oregon. He heard indirectly that there was something happening today in Portland around Electric Vehicles and thought it would be great fun to show up. He found our web site and just took it upon himself to drive the 130 miles from Newport to Portland (good to have a Tesla with 240 mile range). Thus this afforded me several things. One, I got to meet him and a fine gentleman and in good humor he was. Secondly, I got to see my first Tesla in person after reading about them for ages. And thirdly, probably not the first but one of the few shots of a Twike and Tesla together. I have a 2kwh pack in the Twike and can go 20 miles, the Tesla has a 50kwh pack and can go 240 miles (and of course top speed is 150 miles per hour). I have him in efficiency but he has me in every other category (except luggage space, I think I win there). Thanks to David for just showing up as he is one of only 3 Telsa vehicles in Oregon (so I hear). In regards to the Twike, it is doing great and it getting regular use as I drive it to/from work everyday.