In addition to motors, motor controllers, and batteries, tires are part of the efficiency chain, both in acceleration and deceleration (regen braking). I anecdotally heard once that tires can be as low as 75% efficient. I don't have a good source for that tire efficiency number, so if someone has a knowledgeable source for actual tire efficiency, that would be great to know.
Thanks, Gary -----Original Message----- From: EV <ev-boun...@lists.evdl.org> On Behalf Of (-Phil-) via EV Sent: Tuesday, January 4, 2022 2:45 PM To: Electric Vehicle Discussion List <ev@lists.evdl.org> Cc: (-Phil-) <philp...@gmail.com> Subject: Re: [EVDL] Regen toll (was: Tesla Y actual wall outlet efficiency) I can assure you that the Model 3/Y Powertrain is way above 85% efficient. 85% might have been reasonable for a mechanically commutated DC motor, but even modern non-Tesla powertrains are better than that! On Tue, Jan 4, 2022 at 3:27 AM Cor van de Water via EV <ev@lists.evdl.org> wrote: > Reason you can't drive as conservatively as you'd like is simply: > other traffic. > If you are alone on a 45MPH road, nobody cares if you want to do 35, > but if 2 lanes of traffic are storming at you doing 55-60 then it is > mightily inconvenient if someone is blocking the road at 35. > The other reason of course is your own time. While it makes hardly any > difference if you are doing 55 iso 60 on a freeway in time difference, > you are still taking an extra 5 min on an hour trip and sometimes that > means missing appointments, so a higher speed may be necessary at > times. > > BTW, I question the 85% efficiency. Not at max (acceleration) power, > but I am under the impression that the majority of the driving is not > done at max acceleration and at lower power levels, the efficiency of > the drivetrain is usually higher. For example, doing a constant 55 on > a flat freeway takes only 15kW while max acceleration is about 6 times > that amount. > 15kW is about 40 Amps while max current is either 200 or 250A > depending on the vehicle. Running at 20% of max also means a Voltage > drop of 20% so resistive losses drop to 4% of max losses when running > at 20% power, so I presume that if max losses are 15% (=85% > efficiency) then the losses at 20% must be much lower, as long as the > *fixed* losses are orders smaller. > Cor, happily regenning before every traffic light that is not green > and for sharper turns. > > On Tue, Jan 4, 2022 at 3:04 AM EV List Lackey via EV > <ev@lists.evdl.org> > wrote: > > > > On 4 Jan 2022 at 22:40, Bill Dube via EV wrote: > > > > > Whatever the drivetrain losses, they at least double when you > > > regeneratively brake. > > > > I see your point, but I think it's a bit academic. Assuming your > > 85% efficiency number, you aren't losing 30% on regen, you're losing 15%. > > You've already spent that other 15% by the time the energy gets to > > the wheels, so it's gone anyway. And 15% loss is a lot better than > > the 100% loss that you get burning it off in the friction brakes. > > > > > If you drive a bit more conservatively, you can avoid expending > > > that energy extra energy in the first place, > > > > Here I agree with you completely. Not using the energy in the first > place > > is better than using it and then recovering some of it. > > Unfortunately, > you > > still have to use energy to move, unless your trips are all > > downhill. :-) > > > > My point is that regen id like partly smoothing out the hills and > valleys. > > With good strong regen, properly used, your energy use for a given > > hilly route is only slightly more than if it were flat. > > > > If you're not in a hilly region, I agree that regen is of less value. > But > > as you say, with modern controllers, you get it essentially free, so > > it's always worth including and using. > > > > One other often forgotten benefit of regen is that it reduces > > friction > brake > > wear. That not only saves you money, it has environmental benefits > > in reducing vehicle particulate emissions. > > > > David Roden, EVDL moderator & general lackey > > > > To reach me, don't reply to this message; I won't get it. Use my > > offlist address here : > > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fevd > > l.org%2Fhelp%2Findex.html%23supt&data=04%7C01%7Cgln103%40psu.edu > > %7C1e17a6cefd4a4d8d0b8208d9cfbabe4a%7C7cf48d453ddb4389a9c1c115526eb5 > > 2e%7C0%7C0%7C637769223232688435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4w > > LjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sd > > ata=uvWOci1nEHtJXpmD3IpRpcsvQRfoAY7XtQXK3g1WE7I%3D&reserved=0 > > > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > We don't devote nearly enough scientific research to finding > > a cure for jerks. > > > > -- Bill Watterson, "Calvin and Hobbes" > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > = > > > > _______________________________________________ > > Address messages to ev@lists.evdl.org No other addresses in TO and > > CC fields > > UNSUBSCRIBE: > > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww > > .evdl.org%2Fhelp%2Findex.html%23usub&data=04%7C01%7Cgln103%40psu > > .edu%7C1e17a6cefd4a4d8d0b8208d9cfbabe4a%7C7cf48d453ddb4389a9c1c11552 > > 6eb52e%7C0%7C0%7C637769223232688435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoi > > MC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&am > > p;sdata=iwq4xCIlzV9Ya4IA4rVFmokj%2Bjw6q2ijD9Q9EURdq4w%3D&reserve > > d=0 > > ARCHIVE: > > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww > > .evdl.org%2Farchive%2F&data=04%7C01%7Cgln103%40psu.edu%7C1e17a6c > > efd4a4d8d0b8208d9cfbabe4a%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C0 > > %7C637769223232688435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLC > > JQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=vmxfcE > > CeAPmRofe0ZDqXUyiF4phKPajOj9VWoatKCSc%3D&reserved=0 > > LIST INFO: > > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Flis > > ts.evdl.org%2Flistinfo.cgi%2Fev-evdl.org&data=04%7C01%7Cgln103%4 > > 0psu.edu%7C1e17a6cefd4a4d8d0b8208d9cfbabe4a%7C7cf48d453ddb4389a9c1c1 > > 15526eb52e%7C0%7C0%7C637769223232688435%7CUnknown%7CTWFpbGZsb3d8eyJW > > IjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C300 > > 0&sdata=QD8KvzbiK7HVcaeh94cNvKJh5HjCIvRiwYCtjIVxWIQ%3D&reser > > ved=0 > _______________________________________________ > Address messages to ev@lists.evdl.org > No other addresses in TO and CC fields > UNSUBSCRIBE: > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.e > vdl.org%2Fhelp%2Findex.html%23usub&data=04%7C01%7Cgln103%40psu.edu > %7C1e17a6cefd4a4d8d0b8208d9cfbabe4a%7C7cf48d453ddb4389a9c1c115526eb52e > %7C0%7C0%7C637769223232688435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAw > MDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=iw > q4xCIlzV9Ya4IA4rVFmokj%2Bjw6q2ijD9Q9EURdq4w%3D&reserved=0 > ARCHIVE: > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.e > vdl.org%2Farchive%2F&data=04%7C01%7Cgln103%40psu.edu%7C1e17a6cefd4 > a4d8d0b8208d9cfbabe4a%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C0%7C637 > 769223232688435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2 > luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=vmxfcECeAPmRofe0 > ZDqXUyiF4phKPajOj9VWoatKCSc%3D&reserved=0 > LIST INFO: > https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists > .evdl.org%2Flistinfo.cgi%2Fev-evdl.org&data=04%7C01%7Cgln103%40psu > .edu%7C1e17a6cefd4a4d8d0b8208d9cfbabe4a%7C7cf48d453ddb4389a9c1c115526e > b52e%7C0%7C0%7C637769223232688435%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4w > LjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdat > a=QD8KvzbiK7HVcaeh94cNvKJh5HjCIvRiwYCtjIVxWIQ%3D&reserved=0 > -------------- next part -------------- An HTML attachment was scrubbed... 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