Some realities are impossible to avoid. Take for example, the fact that, "The best lithium ion batteries in the world still only have 10 percent the energy density of gasoline." This is what Todd Pratt, said is an important guiding principle for Future Vehicle Technologies, which is running its eVaro three-wheeled series hybrid through the Automotive X-Prize's Shakedown Stage in Michigan this week.
Pratt, FVT's vice president, told AutoblogGreen that the crash avoidance "moose" test was no problem for the three-wheeler, but putting the trike through the first battery of X-Prize tests helped the team discover that the battery system is not as robust as they want it to be. Another problem is caused by the car's unusual drivetrain, which is preventing it from reaching 60 miles per hour. The eVaro uses a series hybrid powertrain with two DC brushless motors that connect to driveshafts and thus to the front wheels without any differential or transmission. This direct drive setup means that the motors need to talk to one another, especially when going around corners. Right now, Pratt said:
The result? The eVaro has not yet passed the 0-60 acceleration or the 60-0 braking tests. But, because the FVT team – which started in 2006 with six guys, each with a unique set of strengths – builds almost everything in the car from scratch, the team feels capable of finding and fixing the problems. With so very few off-the-shelf components in the eVaro, it's all on the shoulders of the people who built the parts.They're close, but not quite, so we're getting heating issues in one but not the other. We're also having a problem with one motor fighting the other one. Right at 59 miles per hour, one motor decides to go the other way, so we're working on the software to determine what's going on.
Those parts include a 20 kW proprietary on-board generator that can keep the car going at 60 miles an hour while still charging the battery. When everything is working, FVT promises a 125-mile range on electrify and a 165 mile per gallon equivalent rating. The numbers come from the series hybrid set-up, which allows everything to operate at an optimum level. Pratt said:
The idea is good, but the FVT crew will spend the time between now and the next set of X-Prize trials in June running the car every day to learn more about it – this model has only been on the road for a week, after all, following 18 months of development – and making some suspension changes. Pratt said he knows how easy it is to have a bad day testing:Gas engines really like running at a steady state. They really like it. They don't like accelerating and decelerating, so if you can take a gas engine and just have it run steady and dump that energy into a battery pack and use it when you need it and then have regenerative braking as well, it's a really sweet system.
We felt for Aptera because this is all new frontier. We're all trying to come up with advancements that we don't know the answers to yet.