6 ms·

For the energy consumption per computation, it is supposedly ~10x better. That matters a lot when you have to account for a limited battery/range and cooling/ex

by gibolt 7y ago

For the energy consumption per computation, it is supposedly ~10x better. That matters a lot when you have to account for a limited battery/range and cooling/extra hardware adding complexity to the car.

dragontamer 7y ago
Personally speaking, I never liked this line of thinking. A Tesla has ~70 kW-hrs of energy, and its motor uses all of that power in 5-hours (5-hours x 60 miles per hour == 300 miles). Just round numbers for an estimate. For those paying attention, that's roughly 14,000 watts of power (again: round estimate, but we're probably +/- within a magnitude). Do you really care if your computer makes you use 14100 watts of power or 14500 watts of power?
- steve_musk 7y 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.
  - dragontamer 7y 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 7y 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.
      - dragontamer 7y ago
        > Traffic-Aware Cruise Control is primarily intended for driving on dry, straight roads,such as highways and freeways. It should not be used on city streets. > Warning: Autosteer is intended for use only on highways and limited-access roads with a fully attentive driver. ... Do not use Autosteer on city streets, in construction zones, or in areas where bicyclists or pedestrians may be present. https://www.tesla.com/sites/default/files/model_s_owners_manual_north_america_en_us.pdf https://www.tesla.com/sites/default/files/model_s_owners_man...
        pests 7y ago
        I agree it says not to, but I also eat raw cookie dough and Im sure others do too
      - lathiat 7y ago
        Also this chip is SPECIFICALLY for FSD. Though true that current autopilot is not designed for city streets the "FSD Chip" / Telstra Computer is quite literally designed for slow city driving. And Elon specifically called out the power usage in these low speed scenarios. Also even on the highway you're not using a lot of power in bumper-to-bumper traffic. They also apparently had a power supply limitation in the older cars for retrofit.
- extrapickles 7y ago
  In isolation, the power usage doesn't matter much due to the size of the battery, but it adds up to a considerable range hit if each subsystem in the car is not reasonably efficient. A mile of range lost per component might not seem like much until 10-20 components are loosing a mile each.

by gibolt 7y ago

dragontamer 7y ago

Personally speaking, I never liked this line of thinking. A Tesla has ~70 kW-hrs of energy, and its motor uses all of that power in 5-hours (5-hours x 60 miles per hour == 300 miles). Just round numbers for an estimate. For those paying attention, that's roughly 14,000 watts of power (again: round estimate, but we're probably +/- within a magnitude). Do you really care if your computer makes you use 14100 watts of power or 14500 watts of power?

steve_musk 7y 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.
- dragontamer 7y 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 7y 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.
    - dragontamer 7y ago
      > Traffic-Aware Cruise Control is primarily intended for driving on dry, straight roads,such as highways and freeways. It should not be used on city streets. > Warning: Autosteer is intended for use only on highways and limited-access roads with a fully attentive driver. ... Do not use Autosteer on city streets, in construction zones, or in areas where bicyclists or pedestrians may be present. https://www.tesla.com/sites/default/files/model_s_owners_manual_north_america_en_us.pdf https://www.tesla.com/sites/default/files/model_s_owners_man...
      - pests 7y ago
        I agree it says not to, but I also eat raw cookie dough and Im sure others do too
    - lathiat 7y ago
      Also this chip is SPECIFICALLY for FSD. Though true that current autopilot is not designed for city streets the "FSD Chip" / Telstra Computer is quite literally designed for slow city driving. And Elon specifically called out the power usage in these low speed scenarios. Also even on the highway you're not using a lot of power in bumper-to-bumper traffic. They also apparently had a power supply limitation in the older cars for retrofit.
extrapickles 7y ago
In isolation, the power usage doesn't matter much due to the size of the battery, but it adds up to a considerable range hit if each subsystem in the car is not reasonably efficient. A mile of range lost per component might not seem like much until 10-20 components are loosing a mile each.