Mountain Pass Performance took its Model 3 and put it on the dyno at different states of charge (SOC) to see how the performance of the car changes as the charge on the battery goes down. Can you guess the result?
The analysis came about after I posed the question to Sasha to see if that was something they had noticed by chance or had tested in the past. He shared that the team at Mountain Pass Performance had been thinking about this as well and decided that the time was right to drop it on the dyno for some data-based insights into the impact of battery charge on performance.
The test required that the Model 3 be run on the dyno, then charged up to the next state of charge (SOC) milestone. To present a sufficiently segmented data set, Sasha started at 15% SOC and stepped up the charge 15% at a time, recording a full data set at each step.
The analysis revealed several key insights into the power and torque laid down by the Tesla Model 3 across the data set, including the fact that the torque output by the Model 3 up to 4,500 RPMS is unaffected by the state of charge of the car. That means drivers will get the same torquiness and acceleration off the line, no matter what charge the battery has on it.
Sasha put it like this: “You always get the same amount of torque up until the point of peak power, and the lower the battery is, the lower the power caps off. Then, from that speed — which we have to figure out exactly, but it’s about 50 or 60 kilometers per hour — there’s a noticeable reduction in power.”
The offset is that the lower the charge of the battery, the lower and lower the drop off is for the torque. That translates to less acceleration at higher speeds for drivers. It’s not the end of the world for most drivers, but it is especially noticeable on the freeway. For those who might have noticed and been wondering, it’s not just a perception thing — the car does lose torque at higher speeds as the charge goes down.
On the horsepower side of things, the effects of a lower state of charge are much more drastic. Starting right off the bat, increasing the state of charge directly correlates to noticeable, meaningful increases in power. For example, the Model 3 at a 30% state of charge puts out about 295 horsepower — a full 15 horsepower less than the same Model 3 with a 45% state of charge.
As they stepped up the charge on the vehicle, they noticed a few larger jumps — for instance, the power increased more than at other levels when the charge went from 60% to 75%. Sasha shared that more analysis is needed to fully understand the dynamics of why this happens, but it is certainly an interesting delta.
Farther up the charging scale, they found that, above 90%, the performance essentially flattens out. There is little benefit to performance from charging the car more than 90%. Beyond just not getting much performance benefit from topping the car off, it’s not recommended by Tesla since it puts some extra strain on the battery.
The results from Sasha’s testing at Mountain Pass Performance give us a data-based look at what we knew was happening all along but didn’t have numbers to back up — the performance drops in electric vehicles as the charge or capacity of the battery declines. It also revealed surprising characteristic about electric vehicle torque and how it remains constant regardless of the charge on the battery at low speeds.
The transition to fully electric transportation is well underway, and learnings like these from Mountain Pass Performance shine a light on just how much we still have to learn about electric vehicles as enthusiasts work to vet them out in an increasingly wider range of applications. We know a few things for sure, though, including that they are superior in many ways — including with regards to performance.