In sprint racing, the strategy is simple: Start as far forward as you can and improve your position from there until the checkered flag waves.
In endurance racing, there are a lot more factors in play, and someone on the team needs to put them all together to form a comprehensive strategy the whole team understands. Everything from pit stops and driver changes to tire changes and fueling strategies come into play — especially when the checkered flag is 25 hours away.
At the 2021 25 Hours of Thunderhill Presented by Hawk Performance, one team’s refueling strategy will be far different from that of all other teams. That’s because they’re taking on the longest closed-course endurance race in North America in a pure-electric racecar, with a proprietary powertrain, chassis and body developed by Entropy Racing in Sacramento, Pa.
It’s the first electric car ever to be entered in the event.
Team EVSR has developed a car and strategy that allows for “hot-swapping” batteries during a pit stop. The team can perform the battery swap in as little as one minute, 30 seconds. That efficiency is critical, because the team will need to perform battery swaps about every 44 miles, which the team has calculated to occur every 30 to 35 minutes at Thunderhill.
“A lot of the trick for us is getting the programming right, and the power consumption, so that we can balance our range versus our pit stop needs,” said team owner Charlie Greenhaus.
To swap the batteries, the team lifts the entire body off the chassis, which exposes all its systems, including the lithium iron phosphate batteries. They then lift the chassis independent of the batteries, which disconnects the power source from the car. Weighing in at about 1,850 pounds — about 700 of which is batteries — the car is tuned to produce about 130 to 140 horsepower.
