Efficiency: There are multiple legitimate ways to measure efficiency in terms of energy consumption. What matters is that when one compares energy consumption, that one knows what parts of the energy flow in the system are being measured and compared. A vehicle tank-to-wheels efficiency measurement will show lower kJ/mile than a well-to-wheels measurement. And the well-to-wheels measurement will vary by production and refinery methods, even if the vehicle remains the same. The measurement units may be the same, but what they're measuring can vary, and may not be comparable.
Steel/Aluminum: 3/Y are steel frame as a cost reduction measure. Tesla used aluminum on S/X. Even on bicycles, a steel frame and aluminum frame can be closer in weight than one might assume. That's because aluminum has a brittle failure mode that steel does not. Steel bends/stretches/is ductile when it is approaching its limits. Aluminum tends to crack. The result is to ensure an aluminum frame is strong enough to survive road shock, it must be built from correspondingly larger/thicker parts than when steel is used. On a related note, that also means that there is a distinct advantage to using steel for components that could lead to disaster if they experienced a sudden failure. Aero: Air resistance increases energy consumption at all speeds. It rapidly becomes large at high speeds, as it increases by speed (actually velocity) squared. There isn't a single speed across all vehicles where air resistance becomes the dominant factor. 55 is just a rule of thumb, but isn't actually a special value. A brick may be way under 55. A sleek aircraft may be way over 55. The actual measured effect aero has on vehicle energy consumption is a function of the drag coefficient (Cd) and exposed frontal area. A Prius can have lower energy consumption than a motorcycle in part because it has a lower Cd even though the frontal area is more. (The Atkinson cycle engine also helps). Weight: Weight has some effect of efficiency. It especially as an effect in terms of acceleration/deceleration losses (which may be partially reduced via gentle acceleration/regen). It also increases rolling resistance as a tire deforms (which can be reduced via high tire pressures). Railroad cars have pretty low rolling resistance...steel wheels on steel rail do not deform much from increased weight. Effects on losses: Wh/mile is a function of all of these factors. Which factor dominates will vary by vehicle design, load, and driving pattern. An aerodynamic vehicle will have lower aero losses than a brick. A lighter car will have lower rolling resistance losses than an otherwise identical but heavier car. A slow driver will have lower aero losses than a fast driver. A steady route will have lower losses than a stop and go route that has the same average speed. 3 mi/kWh aka 333 Wh/mi is a decent all around rule of thumb for many EVs including the original Model S. It's enough to cover some electric resistance cabin heating too. More efficient EVs that have better aero, and HVAC heat pumps, and permanent magnet motors, including later updates to Model S, have brought the number under 300. Model 3 and Y can be near 250 Wh/mile or 4 mi/kWh, which matches Mark's observations. On Dec 30, 2021, 11:46 paul dove via EV <ev@lists.evdl.org> wrote: > Well, that’s not how efficiency is measured but I think I know what you > mean. The Wh per mile is mostly a function of weight. Aero starts to weigh > in around 55mph. On conversions a good estimate is weight divided by 10. My > car weighs 3100 lbs with me in it and I got around 300wh/m. Tesla beat this > by making the battery a larger percentage of total weight by using > aluminum. No one else comes close. I think the Bolt is close to the rule of > thumb. > > > Sent from AT&T Yahoo Mail for iPhone > > > On Thursday, December 30, 2021, 8:32 AM, Peri Hartman via EV < > ev@lists.evdl.org> wrote: > > That's very cool to hear. I have heard over the years that the defacto > EV efficiency is about 3 miles per kWh, measured at the battery, or 333 > Wh per mile. So Tesla has done a great job. I wonder what the Bolt and > some other longer range EVs can do. > > Peri > > << Annoyed by leaf blowers ? https://quietcleanseattle.org/ >> > > ------ Original Message ------ > From: "Mark Hanson via EV" <ev@lists.evdl.org> > To: ev@lists.evdl.org > Cc: "Mark Hanson" <markehans...@gmail.com> > Sent: 30-Dec-21 06:17:32 > Subject: [EVDL] Tesla Y actual wall outlet efficiency > > >Hi folks > >My heavy 4400lb Tesla Y is more efficient than I thought, close to EPA > rating, measured 265 watt hours per mile at the wall outlet with a GE KWh > meter over 144 miles various hwy/city driving. The laptop screen car > display shows 220-240 wh/mi at the car/battery which doesn’t include > charger/batt inefficiencies. My previous electric Karmann Ghia 1974 “ELEC > KAR” tag was 330 wh/mi actual at the AC outlet. My Bolt and Leaf are > slightly less efficient than the Tesla but all my conversions over the > years were in the 330ish range, much less efficient than present day > factory EVs. > >Have a renewable energy efficient new year, > >Mark > > > >Sent from my iPhone > >_______________________________________________ > >Address messages to ev@lists.evdl.org > >No other addresses in TO and CC fields > >UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > >ARCHIVE: http://www.evdl.org/archive/ > >LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > _______________________________________________ > Address messages to ev@lists.evdl.org > No other addresses in TO and CC fields > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/ > LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20211230/c0957328/attachment.html > > > _______________________________________________ > Address messages to ev@lists.evdl.org > No other addresses in TO and CC fields > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/ > LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > -------------- next part -------------- An HTML attachment was scrubbed... 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