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Ya if you aren’t using friction brakes, about the only thing that matters is average speed. I’ve noticed that with my Model S—hilly terrain or driving like a dickbag, my battery usage is really only correlated to average speed. Tangentially related: I spent a day autocrossing, with my usage somewhere north of 1700wh/m, and I had used like 15% of the battery. So great auto-x car?
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Oct 10, 2017 20:27
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The efficiency difference between an electric motor working very hard and not hard at all is so small it might as well not exist. What you want to avoid is accelerating into a red light or a stop sign or a corner you need to slow to take. But even then, for the same total trip time, it’s probably superior to approach the corner at the speed limit and not go quite as fast on the open road. Platystemon fucked around with this message at 20:40 on Oct 10, 2017 |
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Oct 10, 2017 20:35
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call to action posted:Even though you're using that lower amount of power for ten times as long, in this scenario? Like, I know the kW peak would be higher over 3s vs 30s, but wouldn't the kWh expended be similar? In the world of frictionless spherical cars on an infinite straight track in a vacuum, the energy used to reach a given speed is independent of the time taken, yes. In that case it's just converting electrical potential energy to kinetic energy. In reality, the increased power draw required to accelerate faster will heat up the battery, the motor, and the electrical conductors, increasing resistive losses, and because you're reaching a higher velocity more quickly, your average speed (and thus aerodynamic losses) will be greater. If it's a normal driving circuit, you'll also reach higher speeds more frequently -- so you might be decelerating from 40mph at every stoplight instead of 32mph, and you'll lose comparatively more energy in the regeneration/braking there. I imagine there are further effects that I'm not thinking of right now. Also I imagine that there's just a psychological thing here. If you're consciously trying to accelerate more slowly, you will probably drive slower overall as well, even if you make an effort to keep your top speed constant. Sagebrush fucked around with this message at 20:44 on Oct 10, 2017 |
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Oct 10, 2017 20:42
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The practical takeaway is that you want to avoid converting between electrochemical and kinetic energy as much as possible*. Acceleration is irrelevant except don't be that idiot who accelerates hard only to brake hard. *excepting the terminal velocity example...
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Oct 10, 2017 20:51
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There is energy to be save on the charging side as well. How do you get charge into the battery faster? You apply higher voltage. But the battery still needs the same charge (amps × time), so the waste is proportional to the overvoltage (turned into heat inside the battery) with a little extra for loss in the conductors.
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Oct 10, 2017 20:52
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In my case, I think I lose in the regen because the car can't regen fully. Not sure if it uses the friction brakes every time you press the pedal, or the battery is too small to charge at high kw, but the indicator on the dash shows it going past regen into brakes fairly often. It makes sense to me that the tesla gets the same wh/km if you drive like a dickbag or a grandma, only average speed.
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Oct 10, 2017 20:57
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Well acceleration isn't irrelevant. Energy expended to aerodynamic drag is the area under the drag/time curve, so if you cut off the corners of that function by accelerating slowly, you will use less energy. Accelerate infinitely slowly, decelerate at the maximum rate possible without using the friction brakes 
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Oct 10, 2017 21:11
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An apparent Tesla Semi test mule has been caught on video: https://electrek.co/2017/10/10/tesla-semi-test-mule-spotted-video-driving-street/ https://www.youtube.com/watch?v=sHNgSMhkoBk https://www.youtube.com/watch?v=l5ag6ckQWiw This same truck was also in the background when the one with the body on it was caught the other day. 
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Oct 10, 2017 23:33
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gently caress B Eco, D mode is my new best friendblindjoe posted:In my case, I think I lose in the regen because the car can't regen fully. Not sure if it uses the friction brakes every time you press the pedal, or the battery is too small to charge at high kw, but the indicator on the dash shows it going past regen into brakes fairly often. Which car is this?
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Oct 10, 2017 23:35
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call to action posted:gently caress B Eco, D mode is my new best friend A3 e-tron IIRC, it's a plug-in so the smaller battery and/or motor-generator probably limits the charge rate.
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Oct 11, 2017 03:11
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Ola posted:When hypermiling EVs in hilly terrain, it's actually better to use no regen and just let the car roll down hill - turns, traffic and speed limits permitting. Storing the potential energy as kinetic energy (speed) to roll up the next hill instead of electric by regen means it isn't converted between energy forms and thus there's less loss. Elephanthead posted:But officer I needed to be going 150 mph to coast over the next hill. You can do this right now in plain jane ICE cars.
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Oct 11, 2017 04:22
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call to action posted:gently caress B Eco, D mode is my new best friend Audi A3 Etron, plug in hybrid. It has a separate 75kw motor plus the 1.4T. I am guessing its the 8.8kwh battery that means I can't charge at full braking. Batteries don't make much sense to me, Im not sure if it means I can charge at 1C (8.8kw?) but then I can run a 75 kw motor off it? 8.8C? That probably only works for RC cars where you see the "C" notation where they measure their batteries in mAh? Or it charges all the cells in parallel but then puts all the cells in series to get a high Voltage?
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Oct 12, 2017 00:03
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wolrah posted:An apparent Tesla Semi test mule has been caught on video: https://electrek.co/2017/10/10/tesla-semi-test-mule-spotted-video-driving-street/ Interesting that they're using a Freightliner Cascadia as a test bench. Saves on integrating your own air brake systems too.
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Oct 12, 2017 01:24
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e E Type https://youtu.be/610Amyhpzzk
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Oct 12, 2017 09:52
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Anyone have a Tesla referral link, or is there a good place to get them (TMC forum I'm guessing)?
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Oct 12, 2017 18:29
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call to action posted:Anyone have a Tesla referral link, or is there a good place to get them (TMC forum I'm guessing)? http://ts.la/christopher6615
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Oct 12, 2017 18:45
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the poi posted:Feel free to use mine : D Cool, if I'm able to badger my grandpa into buying a Tesla, expect a perk in the next few weeks!
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Oct 12, 2017 19:38
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the poi posted:Feel free to use mine : D ! oh dang you beat me. I knew I shoulda checked this thread earlier. well in case person happens to want to buy - http://ts.la/bryan9891
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Oct 12, 2017 21:07
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call to action posted:Cool, if I'm able to badger my grandpa into buying a Tesla, expect a perk in the next few weeks!
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Oct 12, 2017 22:00
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Has anyone purchased a prius prime the most shameful tax credit scamming EV? The seats in the Volt give me a backache.
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Oct 15, 2017 17:16
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Why is the Prime a scam vehicle?
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Oct 15, 2017 17:46
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The Prius plug in was a sham, the prime isn't.
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Oct 15, 2017 17:54
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Frinkahedron posted:Interesting that they're using a Freightliner Cascadia as a test bench. Saves on integrating your own air brake systems too. It's also telling that Tesla is testing a day cab configuration, not an OTR sleeper cab configuration. Electric trucks will be useful for short haul jobs, but not OTR work. CannonFodder fucked around with this message at 07:54 on Oct 16, 2017 |
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Oct 16, 2017 07:51
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CannonFodder posted:They are probably using a Cascadia as a Glider Kit because it already conforms to the massive pile of regulations regarding class 8 trucks. A start is a start. Let's take what we can get.
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Oct 16, 2017 08:28
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It's where you want to cut diesel emissions the most too.
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Oct 16, 2017 10:29
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Hopefully they'll be announcing long term plans for truck stop superchargers to prepare for when long-haul electrics are viable. Even if it's 10-20 years out. building the power infrastructure up to that point, especially in new truckstops makes a lot of sense. You can't charge the truck at home every night, so for that use case, the charger has to come before the truck.
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Oct 16, 2017 15:05
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I will take this as a ringing endorsement of the Prime then, 22k after reducing my 4th quarter tax payment by the credit. (I have a less then 25 mile commute but sometimes have to drive to the boonies so this car makes good sense cents.)
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Oct 16, 2017 15:08
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Powershift posted:Hopefully they'll be announcing long term plans for truck stop superchargers to prepare for when long-haul electrics are viable. Or fast battery swaps.
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Oct 16, 2017 17:11
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VideoGameVet posted:Or fast battery swaps. I'm pretty sure there are standardized framerail widths on heavy trucks to enable compatibility with aftermarket bodies and such, I wonder if this might make cross-brand battery swaps more practical. Even if not, a company running a fleet would likely be standardizing their trucks which also helps.
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Oct 16, 2017 17:22
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VideoGameVet posted:Or fast battery swaps. You still need an incredible amount of electricity going to where those batteries are being charged. Just some quick math, a 9000 gallon tanker load of diesel, 6mpg trucks, one tanker can deliver 54,000 miles worth of truck mileage, or enough for 108 trucks doing 500 miles a day. The cummins electric truck does 100 miles on a 140kwh battery, that's 75,600 kwh to match a tanker of fuel. 3,150kw 24 hours a day or 9,450kw 8 hours overnight when the grid can handle it/power would be cheaper. Even assuming the usage is split over 24 hours, charging a rack of replaceable batteries. Replacing one fuel tanker, and 108 trucks with electricity/electric trucks would use as much electricity as 2,550 houses. Charging 108 trucks overnight would. The infrastructure to the station has to be significantly different. Powershift fucked around with this message at 17:48 on Oct 16, 2017 |
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Oct 16, 2017 17:24
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Powershift posted:You still need an incredible amount of electricity going to where those batteries are being charged. Do we have an idea of how large the battery packs on these are going to be (Kwh?). Also, didn't Scania experiment with some pantograph thing to charge/run trucks on selected roads? 
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Oct 16, 2017 18:23
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VideoGameVet posted:Do we have an idea of how large the battery packs on these are going to be (Kwh?). If you’re putting up pantographs, you’re a pretty marginal leap away from just laying rails and calling it a day.
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Oct 16, 2017 18:41
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MrYenko posted:If you’re putting up pantographs, you’re a pretty marginal leap away from just laying rails and calling it a day. I don't know if I'd go that far. You still have the flexibility that the electric trucks could leave the main route and run on batteries for that part of their run, then get back on the highway and have range be a non-issue. There are of course a million other reasons why I don't expect to see I-80 covered in overhead wires any time soon, but it's not like rail would be able to totally match it if this was to somehow occur.
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Oct 16, 2017 18:53
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If we wanted to be efficient we'd replace all long haul trucking with rail, rail being far more efficient than trucks. And even harder to convert to (full) electric.
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Oct 16, 2017 18:57
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VideoGameVet posted:Do we have an idea of how large the battery packs on these are going to be (Kwh?). Cummins truck: 140kwh, 100 mile range, optional diesel generator to extend range Mercedes: 212kwh, 200km(124mi) range Tesla: ???kwh, 200-300 mile range Nikola: 320wkh, on board hydrogen fuel cell. 800-1,200 mile range electric+hydrogen combined.
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Oct 16, 2017 18:57
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Powershift posted:Cummins truck: 140kwh, 100 mile range, optional diesel generator to extend range Let's say Mercedes gets the normal consumption right with 1700 Wh/mile which we can assume is at 50 mph. Let's say there is 50 miles of pantograph wires on a commonly used road which the trucks can use for sustaining and charging. Sustained power will be 85 kW. With a 212 kWh battery, it should be able to charge twice as fast as a Tesla, let's round it down to 215 kW for a total of 300 kW - that's reasonable pantograph power, isn't it? While it can't charge at that rate all the way to the top, it should get 3/4 full battery from almost empty + the 50 miles "free" on overhead power. If it was more than 50 miles of wires (and why not, Europe is absolutely crisscrossed with them) and the battery was topped up, the truck would pay a lower rate for sustained power. With a progressive rate, it would be a competitive advantage in not drawing too much power as well. Of course trains are better for huge cargo loads and distances, but you need trucks in the mix too and this might work very well.
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Oct 16, 2017 19:27
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I think the idea of electric trucking with pantographs is great. It works for buses all over the world right now, and having what is essentially an electric train that can leave the rails for in-town delivery (which is the sort of range that the battery pack is suitable for) sounds like the best of both worlds.Powershift posted:Nikola: 320wkh, on board hydrogen fuel cell. 800-1,200 mile range electric+hydrogen combined. I would wait until Nikola has produced anything at all before adding them to this list. Right now they're complete vaporware with the release of their first vehicle "planned" for 2021.
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Oct 16, 2017 22:09
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In the US trains already carry a tremendous amount of cargo, usually with diesel electric hybrids. That's not the discussion. The discussion is around recharging many Class 8 Road Tractors at the same time. Most major truck stops have to 4 to 8 fuel lanes, each providing at least 100 gallons of fuel every 15 minutes. In order to charge 4 to 8 tractors with 600 miles worth of electricity simultaneously in 15 minutes would require every truck stop to have an electric substation next door. I love the idea of local and yard trucks going electric. Every time I roll in to FedEx Ground in Hutchins TX I look at that giant roof and imagine it covered in solar panels powering the area. I imagine solar panels on the terminal in Greenville SC giving power to trucks that go back and forth to the Walmart DC, and hey put some solar panels there as well. However, the realities of long haul OTR trucking involving long distances and weight limitations mean they will be using diesel for the foreseeable future. 100 gallons of diesel weighs about 600 pounds and I can travel 800 miles and it takes me 15 minutes to refuel and it actually takes me 7 I just spend more time cleaning the windshield. When I can plug in a cable that will give me 800 miles of range on a battery pack that weighs 600 pounds, I'll be there.
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Oct 16, 2017 22:57
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that 600lbs of diesel also powers a 2600lb engine and 800lb transmission An electric truck could reasonably have a drive train less than half that weight. A 1500lb electric drivetrain and 2500lbs worth of batteries that can be swapped out could feasibly work, but again, to replace the fueling of 108 trucks, which is a small percentage of what a station would see in a day, would take a 10,000kwh substation to re-charge it's batteries overnight. It also opens up a big ugly bag of snakes with battery standardization, leasing, ownership, degradation, damage, etc. We're not talking about every diesel truck off the road once the electrics come though. but on some routes it will make sense very, very soon.
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Oct 16, 2017 23:11
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Powershift posted:stuff
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Oct 17, 2017 00:47
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