How Battery Temperature Affects Acceleration in a Tesla

11 месяцев назад

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I keep hearing people say “State of Charge affects acceleration in the Model 3 the most”. While State of Charge does affect acceleration. The temperature of the battery mid pack is the single most important factor for determining how fast the Model 3 Performance will accelerate. This video will show you why that is.

The absolute quickest acceleration in the Model 3 Performance is achieved when the battery pack temperature is between 125 to 137 degrees Fahrenheit, the State of Charge is 100%, and the motors are as cold as possible. That will give you a “Max Discharge Value” of 629 HP or 462 KW at the battery.

However, this video will look at the cases where those parameters are not at their optimal values.

If State of Charge drops to 87% but battery temperatures remain at 135 degrees Fahrenheit, the “Max Discharge Value” will still be 615 HP. That is only a 2% drop in performance even with less than 90% SOC. However, if we raise the SOC from 87% to 89% and drop the temperature in the battery down to 42 degrees Fahrenheit or 5.8 degrees C then the “Max Discharge Value” will drop all the way down to 365 KW or 496 HP. That would be a MASSIVE 20% decrease in performance from battery temperature alone.

In this case we have increased the SOC by 2% but lost 10 times the amount of performance because the battery is cold. I can’t stress this enough. Battery temperatures affect acceleration so much that the battery SOC becomes irrelevant if the battery is cold.

To illustrate the point even further I tested this with the SOC at 55% and the battery Temperature at 122 degrees F. The max discharge rate was 570 HP. That is almost 70 HP greater than the cold battery at 89%. Imagine keeping up with someone at 89% SOC when you only had 55% SOC.

At 76% SOC with the battery at 119.3 degrees F you still can achieve a 598 HP Max Discharge Value. That is only 5% off the absolute maximum acceleration potential with a ¼ of the battery gone. Even if we go down to 32% SOC of charge with a more normal 88.7 Degree F battery we can still have a 511 HP Max Discharge Value.

We can go as low as 16% SOC with a 118.4 Degree F battery and still have a 496 HP Max Discharge Value. That equals the 496 HP we saw in the earlier example with an 89% SOC and a 42 degree F battery. You can get a similar Max Discharge value from 16% SOC as you can with 89% SOC in this scenario.
This really is important to stress to everyone. However, I must also tell you that my testing has shown that the affects of heating the battery don’t come into play until after 40 mph. If you heat the battery hoping to see 20% or more improvement in 0-60 mph it won’t happen. Cold motors are actually more important for 0-60 mph in the Model 3 Performance.

Once you pass 40 mph and especially after you hit the peak HP at 55 mph you will see a significant increase in performance regardless of the State of Charge.

The lowest Max Discharge Value I have seen was 351 HP at 6% SOC when I drove 283 miles without charging in my 2 year old Model 3 Performance. I still had 18 miles left of range too. However, the car was EXTREMELY slow at that point.

However, there is one benefit to a low SOC. The max regen braking capabilities only occur at a lower SOC with a hot battery.

In sport mode you will only see about 116 HP of regen with a fully preconditioned battery. However, in Track Mode with a 118.4 degrees F battery and with 16% battery SOC I saw 241 HP of regen braking capabilities. That is extremely strong braking from regen alone.

It is important to also understand that the scenarios I have displayed here only apply to the Model 3 Performance. Battery temperature may not affect the Long Range car’s acceleration in exactly the same way.

Eventually I would like to test non Performance models and even the Model X and Model S to see how temperature affects those cars. I have seen several videos that indicate that the Model S Plaid is capable of achieving more than 1,100 HP at the battery if the conditions are optimal. However, that car in particular really needs cold motors and better tires for optimal performance.

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