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Discussion Starter #1 (Edited)

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Pretty strong difference from published expectations.

How is the regen handled on Tesla? I still think GM has better battery technology.
 

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Discussion Starter #3
Also, in case anyone thinks Consumer Reports must have been doing their range testing in city conditions (which would favor the Bolt), they explained their methodology and said most of the testing was done at 65 MPH with the HVAC off.

So the "aero brick disaster" Bolt outperformed 2 much sleeker Tesla models with 20-35% larger batteries in primarily highway conditions, where Teslas should have a big advantage.
 

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Bolt EV is very efficient so if driven at town/city speeds or low speed highway. The large battery will be great for people in those situations. I do wish other manufacturers would force supercharging instead of waiting for 3rd party support. Build out large DC charging stations through central US, etc. Tesla will likely own more than half the EV market until that problem is resolved.
 

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I do not think anybody has proven yet that at 75-80 mph that Tesla miles per kWh is any better than that of the Bolt EV.

It would be interesting to see. It's efficiency, rolling resistance, AND aerodynamic drag, when many folk assume it's entirely aero.
If the Bolt has less kW losses, lower rolling resistance, it could take a fairly high speed for the Tesla to match the Bolt's mi/kWh.

Now the MX series might not match the Bolt at any point depending on the CdA of both vehicles since the MX is really heavy, with greater frontal area.
 

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Interesting article.

A few points to keep in mind. The EPA doesn't test many cars. They use manufacturer data to establish efficiency numbers. GM likely supplies more conservative data to the EPA than Tesla.

Also another point on aerodynamics. There are different ways to test the coefficient of drag so it's hard to compare numbers between manufacturers. Again GM's numbers appear to be conservative. Also drag force while certainly a notable factor above 50mph is only one of many factors that effect vehicle efficiency. Just because a vehicle has a lower coefficient of drag does not automatically mean it will be more efficient on the highway.
 

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I've never been sold on the Tesla Cd and this is just one more piece of evidence. The Cd numbers can be manipulated too easily. In any event, so much for the fantastic aero advantage. It is probably a different story for a Tesla with two motors. I suspect the issue is that with a single reduction gear and one motor you can't have fast acceleration and good efficiency at higher speeds. We may see the same thing with the Model 3.
 

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Discussion Starter #8
I've never been sold on the Tesla Cd and this is just one more piece of evidence. The Cd numbers can be manipulated too easily. In any event, so much for the fantastic aero advantage. It is probably a different story for a Tesla with two motors. I suspect the issue is that with a single reduction gear and one motor you can't have fast acceleration and good efficiency at higher speeds. We may see the same thing with the Model 3.
The Teslas tested were both dual motor setups.
 

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I think the Model S is less efficient for other reasons, maybe induction motors or tires.

Model 3 data on Tesla website leaked an efficiency of 237 watt hours/mile, which is 30% or so better than Model S, and more in line with modern efficient EVs. This is also why they are not advertising battery capacity of the 3.
 

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Tesla makes nice cars, but efficiency has been a low priority for them so far. Their TMS algorithm is terrible, and they've had vampire drain issues since the beginning. Plus it's a big heavy car. So, I'm not surprised. Maybe the M3 will be better.


GM has under-promised and over-delivered on range for the Volt, Spark EV, and Bolt. It's an excellent policy and makes for happy buyers.
 

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GM traditionally under reports their EPA estimates. They're the only manufacturer to do so. Normally I don't trust Consumer Reports when it comes to cars but when you put the cars on the same route then you're comparing apples to apples. And frankly, the Bolt isn't an aerodynamic disaster - it's just long enough to avoid this.
 

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Just read the CR review. It's positive and the Bolt rates near the top of the class. They ding it for interior materials, front seat comfort, a sometimes choppy ride and a "spongy" brake pedal that's "difficult to modulate." CR testers seem to have trouble modulating brake pedals in general.
 

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I would love to see a test say at the Indianapolis Motor Speedway (essentially a big flat oval) where they would put both cars side by side set the cruise control and go until the batteries exhaust. They could do it at 45MPH, 55MPH, 65MPH and maybe even 75MPH. They could use whatever HVAC settings they need so long as they are identical and not changed during the test. Mount some GoPro's and let them go until they die.

As they say, let the better EV win.
 

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It is interesting to see the bolt do well. I have done a couple trips in the 270 mile range and never had the effiency CR was able to achieve, but I drive faster 75-80. Throw in an elevation change and my gom now shows 170-190 miles at a full charge (hill top reserve on). It used to show 210+ prior to the trips, so I am not sure how far back it looks to calculate range.
 

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The Teslas tested were both dual motor setups.
Oops. I see that. The 75 AWD is rated for 259 miles whereas the 75 is rated for only 249. Still think it's tuning for acceleration rather than cruising. I expect the same thing on the Model 3. The Model 3 and the Bolt EV have the same mass but the Model 3 is supposedly faster. Pushing the battery can account for some of that, but gearing has to be involved as well.

You didn't just do this. LOL
 

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Induction motors versus PM motors

Tesla's use induction motors, which should have an efficiency disadvantage over the permanent magnet motors in most other EVs, including Volt and Bolt.

Volts do more power conversion steps in their transmissions, and especially gen 1's, have lossy hydraulic pumps for that transaxle (I remember reading how improving the pump was a big win in effic. for gen2). Tesla's simpler transmission may have an effic. advantage at low speeds, but may suffer more losses at high speed if it must always have the motor spin very fast. I don't know if much about the transaxle in the Bolt- with no ICE to blend in, it should be simpler, fewer conversion steps than Volt.

PM motor and simple transmission could yield a more efficient drivetrain in a Bolt than Tesla M or X. M3 is a new design, I'd expect improvements in the motor design and in the effic of the electronics, but cost cutting could have won. Kinda like the gen2 Volt motors using less magnet than the Malibu hybrid, and winding up with lower MPG ratings.

-Lumos
2014 gen 1
 

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Pretty strong difference from published expectations.

How is the regen handled on Tesla? I still think GM has better battery technology.
Tesla does a great job with high speed charging, but nobody is as good with regen as GM. Their blended braking is brilliant.
 
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