top | item 21085815

(no title)

steve_musk | 6 years ago

Sure if you’re driving only on the highway. What about driving around the city at 5-20 mph? Tesla’s end goal is to have autopilot do everything, so if they are serious about it then it makes sense to consider the impact at non-highway speeds.

Let’s say you are driving at an average speed of 20 mph - then by your estimate you’re using ~4666 watts. So if your chip is 500W it’s a significant portion of the power budget.

discuss

order

dragontamer|6 years ago

> What about driving around the city

Autopilot is highway only for now. I'd expect the chip to be off, at least with the current version, if you are on city roads.

But sure, if you're driving on city roads, lets really math it out. You have 70kW-hrs and maybe you're going 20 mph. Lets call that 4600 Watts of energy usage. Lets say you have a 500-Watt computer, for a total of 5100 Watts.

You can run your car for literally 13-hours at that power-usage. 70 kW-hrs is a lot of energy storage. A 4600 Watt power-usage results in ~15 hours of runtime instead.

Not a big change. And these are estimates only, I don't actually know what the energy-consumption metrics are for city vs highway. But these "poor calculations" are still good enough to realize that even a 500W computer is well within the power-budget of a 70,000 Watt-hr battery pack.

----------

Absolute worst case scenario (for the computer): you are going 0 MPH. Parked in a parking lot using only the computer. That means 100% of the power usage goes into the computer. What happens with a 500W computer?

Well, 70 kW-hrs can last 140 hrs at 500Ws of usage, that's over a workweek: over 5 days of computer usage. Are we seriously worried about the miniscule power usage of the car's computer system when a 70 kW-hr battery is in the car?

pests|6 years ago

Highway only? My roommate has one, I don't think he's ever not using autopilot even on side streets. He might only use the brake or accelerator a few times in a whole days driving.