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virtualdom | 5 years ago

To answer my own question:

Assuming 2KWh / mile average consumption[1], an EV semi powertrain would be pulling ~120KW continuously from the battery. Even at 90-95% efficiency, there will be 6-12KW of waste heat available in the powertrain, more than enough to heat the cabin in cold weather. Modern EVs actually do scavenge waste heat from the battery and motors for cabin heating[2], unlike the EVs tested in the cited article.

But even without using the available waste heat, a 6KW resistive cabin heater would only use 18KWh over a 3 hour drive. For a cheap passenger EV, this could be 20-40% of the battery, but for a semi with 500 miles of range, 18KWh would only be 1-3% of the battery.

Put more succinctly, the battery in an EV semi would be 5-10x larger than the battery in a passenger EV, but the energy required to heat the cabin will be roughly the same. So the effect of cabin heating on range loss would be 5-10x less on a EV semi than a passenger EV.

I would remove this line from your post: "plus the batteries lose > 40% of their range in cold weather" because I don't think that claim is supported by any source, or by basic logic and math, in the context of a semi truck.

[1] https://www.tesla.com/semi [2] https://jalopnik.com/the-tesla-model-ys-octovalve-and-coolin...

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cdreynolds|5 years ago

I hope you are right, because that's better for the environment. Independent testing of the Tesla Semi will prove or disprove all these claims. Regardless, the huge point here is that we offer a retrofit solution that solves carbon emissions from trucking now.

virtualdom|5 years ago

> Independent testing of the Tesla Semi will prove or disprove all these claims.

It sounds like you think it is fine to make claims that are unsupported by any evidence, or by basic logic, until a counter-example to your claims is physically available for independent testing. That’s unbelievably disappointing to hear.

"Our device works perfectly in all climates, while electric vehicles lose more than 40% of their range in cold weather, making them impractical for many parts of the world.”

Having this tagline on your website is ignorant if you hadn’t done the math, and intellectually dishonest now that you have.

I agree that the “huge point” of this announcement is the device you’ve created. You just don’t need to resort to misinformation to promote your product.