While doing a mileage run, I shot this photo of the Tango's shadow.This nicely illustrates how easily it fits in half a lane.The new Headway LiFePO4 pack is now delivering over 30 kWhrs under freeway driving conditions at 60 mph. This morning my wife Alice and I drove 122.5 miles on a charge on relatively level freeway (a couple hundred feet of elevation change). This worked out to 249.8 Wh/mile. The Progressive Automotive X-Prize requires 100 miles of range and an equivalent of 100 mpg. This is defined as MPGe. The conversion used is 32.82 kWhrs = 1 gallon of gasoline. This means that we need to achieve 328 Wh/mi or better to qualify. This is as measured at the wall receptacle, so charging and battery inefficiency must be considered. A couple of days ago, we drove 80.7 miles with a 252.75 Wh/mi reading from on-board instruments, while the kWhr meter on the wall read 24 kWhrs. That works out to 297 Wh/mi. That's an 85% efficiency. After equalizing the cells all night, the meter at the wall read 25 kWhrs or 310 Wh/mi, which is still well within the requirement--all this with an extra 200 lbs of lead ballast and a second passenger.
With 100 more volts and much less sag from the battery pack, the Tango is now much much faster than with the lead-acid batteries that have been used for all events in the past. We haven't run the 1/4 mile with the Headways yet, but look forward to writing that post.
