Wednesday, June 30, 2010

Tango passes X-Prize Knockout. Consumer Reports, regarding emergency-avoidance maneuver: "And the sleek, fast, orange Tango passed on the first try."

I'm just returning now from a successful completion of the X-Prize Knockout event. Staying in Bismarck ND tonight, I should be back in Spokane Tomorrow. I'll be taking the Tango back to Finals at Michigan International Speedway (MIS) on July 18 through 30th.

During the Shakedown event last month, Consumer Reports captured the Tango in the 0 - 60 acceleration and braking events, but didn't get the the emergency-avoidance (moose test or double lane change, as it's often called), before I had finished it. During Knockout, to the best of my knowledge, the Tango was the only car that passed the test on the first try. This time Consumer Reports had a camera fastened to my windshield. I haven't seen the video yet, but hope to soon. Here is the article just posted today with their photo above. Consumer Reports


Saturday, June 26, 2010


We are still contenders in the Automotive X-Prize competition due to no small contribution from other teams and volunteers. We've now completed the first week of the Knockout stage which consisted of economy runs which require 67 MPGe (Miles Per Gallon Equivalent) and a range, in our class, of 67 miles at 60 mph. We completed these easily, of course, however, the urban and city driving cycles brought the Tango down to 86.8 MPGe due to lack of regen which we sacrificed in order to have the extreme torque of two series-wound traction motors. The Tango, being one of the heaviest vehicles in the competition, weighing in at nearly 3,300 lbs, (the same weight as a Subaru Outback) has a huge handicap for stop and go and a smaller handicap of rolling resistance. The Tango does have the benefit of half of a normal car's frontal area which helps with reduction of aerodynamic drag at higher speeds.

The real problem for the Tango in this competition was being prepared with all of the data logging instrumentation and other requirements for passing the tech inspection. In addition, despite the fact that the Tango has nearly 200 lbs of lead ballast in the bottom of the battery box, because that was added voluntarily, the rules still required another 38 lbs of ballast to be added to make up for some of the production equipment not included (anti-lock brakes, air bags, etc), and the weight differential between my weight and 200 lbs. This was added to the front trailer hitch receiver in the form of a block of steel 3" x 4" x 11", just 4" off the ground in the front.

Before leaving for Michigan for the X-Prize Knockout event, my wife Alice and I had just completed a week long installation of a battery management system in Thomas Greither's Tango. This took place at Pacific EV in Seattle where we only got 2 to 4 hours of sleep a couple of the nights. Following the successful installation and delivery of the Tango with 32 kWhrs of Headway cells (120 mile range at 60 mph), we had very little time to install the new 10"-deep stainless battery box in the X-Prize Tango. Tim Foster of Patriot Motors in Spokane volunteered his help with the installation which made it possible for me to make the solo drive to Michigan International Speedway in time not to be disqualified last Sunday. We are the only Automotive X-Prize team with only one member.

Upon arrival, with less than 2 hours of sleep for the whole drive towing the Tango and tool boxes, it was quite discouraging to feel so unprepared to have all of the new battery management system (BMS) modifications installed and the whole data acquisition system still in a box with the instructions still unread, plus a new 50 page booklet of rules, that it seemed there would be no way to make it through tech inspection, which would mean expulsion.

I mentioned my discouragement to several of the X-Prize staff, and to my amazement, several teams sent their team members to help. I feel like I was almost adopted by the Li-ion motors who had engineers and technicians helping to get the Tango prepped as if it was their own team. In particular, Luc Pham focused on the data acquisition system, while Abiyu Negede drew up a schematic for the relay board for the BMS and then soldered it up. I checked it out the next day to find it flawless. I hooked it up and the Elite Power Solutions BMS worked perfectly by shutting down the current on the charger at high cell voltage precisely while shutting down the AC input to the charger on over temp. It also shuts down the motor controller on either a low voltage or high temperature alarm. Davis Nguyen and others of the team were always there to help push the Tango to the Track, (a requirement for all cars), and all constantly available and asking to help.

I owe the deepest debt of gratitude to all of them and other teams that also helped in any way. Brad with the FVT team helped immensely with the programming of the MoTeC dash to transmit to the data acquisition system. Their team is a direct competitor in our class, yet treated us as their own. The West Philly team was also helping by running errands to town for parts and even went to a steel company for me in Jackson, many miles away to bring back the ballast.

The X-Prize has been a great learning experience for all of us and seems that that is more important to all than who wins, despite the high stakes.