Dual motor efficiency

[Zoomit]

Very true. Regen is not of much use when you gotten used to driving electrics. The smaller the battery, the more important to not use regen as it's a waste. Looking at the video above you get only 50% back. (IRL might be less too, but the video says 50%) Better of not accelerating so much and save the full 100%

I'll disagree. If you're hypermiling, that's an atypical scenario where the losses of regen should be considered. For normal driving though, regen is critical to the overall efficiency of electric vehicles.

You cannot interpret that video to say that regen is only 50% efficient. Some of the kinetic energy at the peak speed is lost from aerodynamic and tire drag forces during the deceleration and hence is unavailable to be recuperated by the motor into the battery. When considered independently, I understand regen is closer to 80% efficient.

 

[Zoomit]

0k....bottom line. do I order awd or rwd?
leaning toward awd, heavily, but the reasons are softening. Looks like resale may be more important than regen. hate to buy for resale.

You should get AWD, because Tesla needs the profit and it doesn't cost me anything.

More seriously, I'll repeat what I said up-thread, "Regen efficiency should not be a discriminator when choosing between RWD and AWD."

AWD is better in nearly every way, efficiency, traction, handling, torque vectoring, acceleration, more even tire wear, stability... and it's not a lot more cash.

This ^, understanding that only you can say if it's really "not a lot more cash".

 

[dgpcolorado]

... At 60kW they only have to limit regen braking if you are at the upper end of a range charge.

The regen is also limited when the battery is cool or cold. I frequently have regen limited to about 30 kW, or a bit less, when my battery is cool, until it warms up a bit while driving. A cold battery might have little or no regen, even at a low SOC. It is something those of us in cold climates have to consider. Charging at the last minute warms the battery somewhat and can help with that.

In other words the battery is limiting factor for regen braking, not the physics of braking.

Just so!

 

[dgpcolorado]

0k....bottom line. do I order awd or rwd?
leaning toward awd, heavily, but the reasons are softening. Looks like resale may be more important than regen. hate to buy for resale.

I would greatly prefer AWD because it would help with getting up my steep curved driveway in winter (I have chains for my RWD S for the times the driveway is too slick to get up). This isn't something you would deal with in Tucson!

I'm guessing that AWD will be a $4000 option on the 3. Is it worth that to have somewhat better handling and efficiency (range)? Depends on your wallet and preferences.

My options list is pretty simple: 1) Bigger battery (likely includes Supercharger access if it's an option on the base model), 2) AWD. After that there isn't much that I'm willing to pay for. Much as I'd like a heated steering wheel — much more useful than heated seats — I'm not willing to pay $1000 for the cold weather package to get it. I have no use for Auto Pilot, given where I live, so I wouldn't pay extra for that.

...I rather like the extra frunk space and on long trips I will be using it to carry a spare tire, since I prefer to be able to self-rescue when I am very far from home or a city.

don't you need two sizes of spare?

No, my car has only one wheel size: 19 inches. I bought a spare wheel and had a tire put on it for use on long road trips (otherwise it stays home).

When it comes to buying new tires — my mountain driving is very hard on tires — I will buy three and use the one on the spare wheel as the fourth. Then I will put the best of the old tires on the extra wheel for use as the spare.

 

[Northrop]

For normal driving though, regen is critical to the overall efficiency of electric vehicles.

You cannot interpret that video to say that regen is only 50% efficient. Some of the kinetic energy at the peak speed is lost from aerodynamic and tire drag forces during the deceleration and hence is unavailable to be recuperated by the motor into the battery. When considered independently, I understand regen is closer to 80% efficient.

No, for normal driving regen are a failure. Plan your driving and don't waste energy on brake/regen. You can do this without hypermileing to the extreme. It's just about chilling a bit, not driving aggressive.

As for regen efficiency you need to feed the car with power from the battery to get it moving, efficiency of 90%-ish. Then when braking with regen you are feeding it back to theb atter with efficiency of 90% at it's best? I doubt it's 90% as you see model S overheating way faster if regen are on. To this efficiency numbers you need to add tire traction, roll resistance etc. I think the 50% in the video are a good mean value to aim for. Again remember you first need to make the car moving with energy before you can regen it. Atleast the video is an IRL test and the best shoot at it so far.

 

[AZ Desert Driver]

I would greatly prefer AWD because it would help with getting up my steep curved driveway in winter (I have chains for my RWD S for the times the driveway is too slick to get up). This isn't something you would deal with in Tucson!

I'm guessing that AWD will be a $4000 option on the 3. Is it worth that to have somewhat better handling and efficiency (range)? Depends on your wallet and preferences.

My options list is pretty simple: 1) Bigger battery (likely includes Supercharger access if it's an option on the base model), 2) AWD. After that there isn't much that I'm willing to pay for. Much as I'd like a heated steering wheel — much more useful than heated seats — I'm not willing to pay $1000 for the cold weather package to get it. I have no use for Auto Pilot, given where I live, so I wouldn't pay extra for that.


No, my car has only one wheel size: 19 inches. I bought a spare wheel and had a tire put on it for use on long road trips (otherwise it stays home).

When it comes to buying new tires — my mountain driving is very hard on tires — I will buy three and use the one on the spare wheel as the fourth. Then I will put the best of the old tires on the extra wheel for use as the spare.

just curious. does a spare fit in the frunk?

 

[jerry33]

just curious. does a spare fit in the frunk?

Depends. Not if you have any kind of "D". 19" tires can fit in non-D (this somewhat depends on your car because the size changed over time) but many folks aren't comfortable having something that solid in the crumple zone. Others have used a BMW space saver spare.

 

[dgpcolorado]

just curious. does a spare fit in the frunk?

Sort of. It won't lie flat in that space if fully inflated. Others have said that it will if pressure is dropped to 35 psi but I haven't tried that yet. This is with the large frunk in a RWD Model S. I don't think that there would be any way to get a spare in the frunk of an AWD model and I'm not sure about the just released refreshed version of the Model S, which is reported to have a reduced frunk even for the RWD version.

I really don't want a heavy, loose wheel/tire in the trunk in the event of a crash and would have to come up with a way to secure it to put it in the back. I presume that Teslas in Australia have a spare tire and wonder where and how it is installed.

There is a thread on spare tires and others have found that a BMW compact spare fits the car. But I wanted a tire that I can use for hundreds of miles if necessary. I view it as insurance against a flat that I can't repair with a plug kit, so that I can continue with a long trip without having to arrange for a very long tow to a city. I gather that the vast majority of Tesla owners neither need or want a spare tire because calling for a tow in the unlikely event of a flat is easy for them. Not so for me, given where I drive.