Supercharger Throttling Explained

I stopped by the San Mateo supercharger today and chatted with the Tesla rep that’s assigned to the location. It was like a full service gas station btw, I pulled in, and there was a Tesla capped gentleman putting the charger into my car. Nice touch Tesla!

So we got to talking and I asked why this time I was getting around 250 miles per hour charge, and last time I was there I only got around 125 miles per hour charge. In comparison, in Tahoe I’ve recently gotten up to 360 miles per charge, so I was curious why all the different charge rates.

charge rate

He basically confirmed that Tesla throttles customers that are topping off. If you head to the supercharger with an 80% full battery, you are effectively using the Supercharger to save charging at home. Tesla knows this and throttles the speed at which you can charge to discourage this behavior and save energy/spaces for traveling customers. Today I showed up with 1/3 full, aprox. 100 miles left and received a strong 250 miles per hour charge.

He also confirmed that the superchargers are capable of up to aprox. 370 miles per hour.

supercharger rate

I know there are a lot of articles out there focused on the physics of slow charging an almost full battery, but the entire conversation today was around policy and not science. So while it’s more than possible science is 100% to blame for the slower charge rates when near capacity, the agent today came off well spoken and trained around the policy approach to throttling. Seems like an odd message to send if all of this can be explained by simple charging science.

My personal opinion is that this seems like a fair approach. I’d much rather Tesla throttle customers, than start to limit who can charge and when. Throttling encourages a behavior without actually policing. I have heard that Tesla will send you a letter if you are abusing free supercharging, but again, their current approach is to encourage behavior, not to actually police your behavior. Hopefully this approach continues as the light touch is more fitting with the Tesla brand than cracking down through punitive actions.

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2 thoughts on “Supercharger Throttling Explained

  1. Did the gentleman in the hat explain why you were only getting a rate of 250mph instead of 360 since you were less than 80%? Seems like this is more easily explained by (1) charge tapering and (2) people in Tesla hats not knowing everything.


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