Roadster 3.0

[JRP3]

I don't know how much of the PEM would need to be changed for supercharging -- and no one here's quite put forth any of the factors to be considered.

Actually I have in this thread, the PEM is bypassed when supercharging, other than possibly monitoring state of charge.

If tesla were to add in SC to the roadster there would be an switch to disconnect the PEM and connect it directly to ESS.

Exactly. I should also point out that the PEM doesn't care about the specific battery chemistry as long as the operating voltages are in the same range.

 

[Jaff]

But they can only do so much with the existing Roadster...whilst it is a little hard on the Ego (a friend of mine keeps asking me what it will be like with my wife having a faster car (P85D) than mine ;-) , the Roadster will reappear in a few years and regain "King of the hill status"...

Sounds about right to me. What's ironic is that about a couple years ago there was a big Roadster proponent at Tesla working on cool things like limited-slip differentials, revalved suspensions, new Firmware to yield about a 10% better torque curve with almost no additional power consumption, etc.

Unfortunately, Joost de Vries left Tesla before these things came to market - and apparently they died with his departure. I think most owners would rather have a better performing Roadster than a travel further on a charge Roadster. Sigh.

If Elon really wanted to do something cool for Roadster owners, he'd have gone in a different direction. Making Roadster the longest travel on a charge production BEV while the large 2-ton Model S is the quickest from 0-60 is completely backwards when you think about it.

- - - Updated - - -

TMC "beat suptin" to death?...no, say it aint so...this place would never do that...:wink::biggrin:

Yes, it is
The forum has beat this to death. No Supercharging!
If you want to hit the Supercharger Network ....... Buy an S, reserve an X, pray for an E.
Tesla is allowing us to stay on the road with our daily commutes, weekend road trips and quick nimble slalom driving (when needed) for a lot longer with this upgrade. Audi hasn't done **** for my 2004 TT, Volkswagon hasn't done squat for my 2000 turbo Beetle and Honda surely hasn't even thought about how to repair my 2005 hybrid whose battery is dgrading to extinction.
Put your stuff into perspective and accept that your 163 and my 170 can be doubled...... Very cool!

 

[bonnie]

I'm just not following your logic. Tesla literally could have polled 2,500 Roadster owners and said, would you prefer 1) a pack with 400 miles or 2) a lighter pack with 250 miles that makes the car weigh xxx pounds lighter, accelerate faster, etc.,. (but will require some suspension tweaks) and/or 3) supercharging, etc.,.

Then let me help. Tesla didn't need to do anything, much less poll Roadster owners. What they are doing is meeting an obligation by sourcing a battery to replace obsolete tech to those who bought the battery replacement option. To choose to do anything else would have meant additional engineering time, time that would take away from advancing their current product line (cost of lost opportunity).

Hopefully this helps you also understand my comment of 'the market just isn't there'. It isn't. No sane company would put engineering time into providing new tech and options to a market that is not only small, but will become smaller over time (unfortunately). There is no hope of market growth in this particular case. However there is a commitment to those who bought the battery replacement option - and everyone benefits. If they'd focused instead on supercharging, they'd still have to identify a battery replacement path.

I get that there are plenty of people wanting different things. What I don't understand is why some think this should be a vote (via a poll), with the implication that Tesla should do what the majority want. The first priority is a replacement battery. If they do anything more in the future, that's up to them.

And I'm not even going to address your hyperbolic comment of 'I don't think I understand anything of what you're saying in this thread'. No need to be rude, especially when others have understood exactly what I said.

 

[Doug_G]

Just to add to Bonnie's comment... there's a good reason why Tesla is building a larger capacity Roadster pack rather than a lighter weight one: it's a LOT less engineering investment.

All they are doing is replacing the cells and tweaking the firmware. That's it. Everything else is remaining unchanged.

And that is totally appropriate. They had to do an updated battery for the Roadster to meet their prior commitment to provide replacement packs, because the original cells are no longer available. This is the cheapest way to do that. The fact that it is higher capacity is not just a side-effect; it is unavoidable!

 

[techmaven]

Then let me help. Tesla didn't need to do anything, much less poll Roadster owners. What they are doing is meeting an obligation by sourcing a battery to replace obsolete tech to those who bought the battery replacement option. To choose to do anything else would have meant additional engineering time, time that would take away from advancing their current product line (cost of lost opportunity).

I agree and you may very well have some inside knowledge on the path they would take.

Hopefully this helps you also understand my comment of 'the market just isn't there'. It isn't. No sane company would put engineering time into providing new tech and options to a market that is not only small, but will become smaller over time (unfortunately). There is no hope of market growth in this particular case. However there is a commitment to those who bought the battery replacement option - and everyone benefits. If they'd focused instead on supercharging, they'd still have to identify a battery replacement path.

This is precisely why I thought they would use Model S cells. They already source these in the millions and these are probably the cheapest cells they can get on a per kWh basis. They already know these cells. They already have the BMS for them. They already made a machine to build sheets of these with integrated cooling jackets and fuses. They just need to build sheets of a slightly different size and configuration. If they can make the electronics the same boards, they simplify their supply chain and running yet another batch later on won't be as hard since they will likely still be making Model S parts for quite some time. Further, the price of the cells dominates the price of the upgrade. Figuring out how to bypass the existing PEM for charging at least is probably the biggest issue which doesn't seem all that insurmountable. At least, it would have been very interesting to be a fly on the wall when they were discussing the various approaches.

 

[scaesare]

I don't know how much of the PEM would need to be changed for supercharging -- and no one here's quite put forth any of the factors to be considered. But if the pack is all-new, then it seems like supercharging should be possible with a swap of the charging receptacle and not a whole lot else hardware-wise. This could be my naivete.

I've seen several discussions on the forums outlining some of the factors. Between those comments and what we can glean from how supercharging works on the Model S:

- The thermal management system in the car is designed to work in conjunction with supercharging. Many Model S owners have experienced the TMS operating at maximum during a supercharger session, which makes sense as a known characteristic of Li-ion cells to to generate more heat when charging than discharging. It's quite possible the TMS components (compressor, evaporator coils, heat exchanger etc...) in the Roadster is not up to this task.

- The thermal cooling plumbing in the pack itself has to manage the additional load of supercharging, yet do so in a constrained space. There may be packaging issues attempting to make that work.

- There is switch-gear to transfer the input connection directly to the pack instead of the on-board charger. This has to be controlled by the battery management system

- The BMS would have to implement both the physical communication layer and the higher level protocol to be able to talk to the spuercharger

- The BMS would have to be capable of commanding the supercharger with regard the voltage/current profile it requires for the battery charge curve (the BMS is what controls the charging session, not the supercharger)

- The charge port would have to be changed (or a new one installed)

- Cabling to/from the charge port would have to be installed

- Instrumentation and displays would need updating



The effort would appear to be non-trivial on several fronts...

 

[techmaven]

- The thermal management system is designed to work in conjunction with supercharging. Many Model S owners have experienced the TMS operating at maximum during a supercharger session, which makes sense as a known characteristic of Li-ion cells to to generate more heat when charging than discharging. It's quite possible the TMS in the Roadster is not up to this task.

- The BMS would have to implement both the physical communication layer and the higher level protocol to be able to talk to the spuercharger

- The BMS would have to be capable of commanding the supercharger with regard the voltage/current profile it requires for the battery charge curve (the BMS is what controls the charging session, not the supercharger)

Use a Model S BMS. The Supercharging protocol already deals with dynamic charge rates given at least temperature and SoC. If the Roadster's fans are not as good, then it'll just Supercharge slower just like Model S's that are plugged in when hot.

- There is switch-gear to transfer the input connection directly to the pack instead of the on-board charger. This has to be controlled by the battery management system

It is likely that the contactor would have to be changed out anyways, so the switch gear replacement is probably relatively trivial if that is the case. Again, if using the Model S BMS, the connection and logic for this would be given.

- The charge port would have to be changed (or a new one installed)

- Cabling to/from the charge port would have to be installed

This part would be interesting even if Supercharging wasn't an option... I wonder what the installed base of 80A HPWC is compared to 70-80A J1772.

- Instrumentation and displays would need updating

This would have to be done in some way anyways.

 

[bonnie]

I agree and you may very well have some inside knowledge on the path they would take.


This is precisely why I thought they would use Model S cells. They already source these in the millions and these are probably the cheapest cells they can get on a per kWh basis. They already know these cells. They already have the BMS for them. They already made a machine to build sheets of these with integrated cooling jackets and fuses. They just need to build sheets of a slightly different size and configuration. If they can make the electronics the same boards, they simplify their supply chain and running yet another batch later on won't be as hard since they will likely still be making Model S parts for quite some time. Further, the price of the cells dominates the price of the upgrade. Figuring out how to bypass the existing PEM for charging at least is probably the biggest issue which doesn't seem all that insurmountable. At least, it would have been very interesting to be a fly on the wall when they were discussing the various approaches.

So first - I have no inside knowledge regarding these decisions. (And if I did, I would not be posting!) My responses are based on personal engineering, engineering management, and manufacturing experience, nothing else.

Regarding use of Model S cells: I have no doubt that Tesla engineering selected the most expedient path, requiring the least engineering, in choosing the cells for the replacement battery. What appears to be the simple and obvious choice at first glance is often far more complex. (Boo!)

Would I like supercharging? Hell YES! That's why I'm in line for a Model X.

 

[PokerBroker]

This is so much more black and white than everyone is making it to be. Tesla, same as all other auto manufacturers, is in the business of selling NEW cars and has ZERO obligation to invest any money into old models aside from keeping them running during warranty and providing for parts thereafter. Any investment of time and resources into a car that has already been sold is at a loss and those dollars are much better invested into future products. Tesla is only obligated to make an original spec battery available to us and no more. Everything else they have done is a blessing whether you think they have gone far enough or not. Even if supercharging was possible it would be a losing proposition for them to invest into making it happen. This complaining is getting absurd. It is like saying that Apple should upgrade the battery and lightning adaptor in your old iPhone so it has current technology... No, buy a new one.

 

[scaesare]

Use a Model S BMS. The Supercharging protocol already deals with dynamic charge rates given at least temperature and SoC. If the Roadster's fans are not as good, then it'll just Supercharge slower just like Model S's that are plugged in when hot.

The level of integration between the BMS and the other car systems is likely very significant. (For example, the BMS in the S relies on interaction with the dash console computer, the TMS, etc... those systems are either different or not present in the Roadster. Re-designing those dependencies is again non-trivial.

What's more, you lumped in all the thermal management issues in with your BMS response. The TMS and BMS are separate, and even if they did overcome the challenges of integrating the Model S BMS in to the Roadster, it doesn't solve the thermal issues. It does no good to figure out a way for the BMS to request pack cooling that the car can't deliver.

It is likely that the contactor would have to be changed out anyways, so the switch gear replacement is probably relatively trivial if that is the case. Again, if using the Model S BMS, the connection and logic for this would be given.

The contactor in the pack is different, and completely separate from, the switch gear in the car. In the Model S it's under the rear seat with the chargers. You would have to find a place for this in the roadster, retrofit this in, change cable paths to it from the new charge port, change the cable path from the pack to it, change the cable path from the PEM to it, install signaling circuits from the BMS to control it, implement chargeport locking circuitry. I repeat: non-trivial.

This would have to be done in some way anyways.

With new cells and a different range, the effort will require re calibrating the energy usage profiles, CAC calculations, etc... I'm not sure the actual format and layout of the displays changes at all... just different numbers in the existing displays.

Supercharging, on the other hand, requires implementation of additional screens and features.

The phrase I continue to repeat is: non-trivial. Could Tesla do it? Perhaps. But possibly not without some compromise (i.e. not enough internal space in pack to implement upgraded cooling plumbing without removing some cells... or not enough thermal management HVAC evaporator coil surface to allow cooling at anything above 30kW of charge power, etc...).

The earlier posts that suggest that just because these issues have been engineered for an entirely separate platform (the Model S), they should be relatively straightforward to implement in the Roadster are not taking into account many factors.

 

[ChadS]

My best guess is that they did just do the bare minimum to engineer replacement battery bricks. But, given the constraints of fitting in the existing sheet design, as well as size and electrical characteristics, that fell short of Elon's pre-announced 400 miles. So, they also did some aero and tire work to hit Elon's mark. Even then, they couldn't get it done in time for the promised end of the year, so came out with an outline announcement instead.

That's very close to my favorite theory. My only change is that I suspect (though I could easily be wrong) that they did find it possible to get near 400 miles; just too expensive because it was using bleeding-edge cells. Musk may not have worried about the expense at first - saving Roadster owners money has never been a priority - but maybe after more reflection on how to handle the price difference for those that pre-paid for a replacement battery, plus potential buyer perceptions, they decided to do something cheaper.

Both of our theories explains why they did the tire/brake/aero improvements even though they didn't have to legally - they were trying to make good on Musk's early claims despite a smaller than planned battery.

Another impossible-to-prove theory is that Musk planned this all along. While the tire/brake/aero work was not necessary to meet legal obligations to Roadster owners, he was concerned about other automakers pre-announcing cars with ranges equal or slightly better than that of the Model S; but as Tesla is battery constrained they can't release bigger packs for them without reducing the number of cars they can build. He wanted to announce a car with significantly more range, both to capture customer imaginations and to keep pushing the other automakers. Adding range to the Roadster was a way to make a long-range announcement without reducing the number of Model S they can build.

They are a business, and they're doing more than they have to or that other automakers do for past buyers, and I'm happy. (While Supercharging would be cool, I just can't see any business case for that so I never expected it). I'm concerned, though, that 400 miles still seems well beyond the likely EPA range based on the changes described. I don't need 400 miles so it doesn't matter to me, but I fear we will have another P85D-ish scandal on our hands once the range details become public. I like that Musk pre-announces things; I just wish the announcements set more appropriate expectations. Meeting expectations is key to consumer satisfaction.

Of course, producing cars far different and better than other offerings is another key to consumer satisfaction. That's why we can have so many people simultaneously complaining, and yet not considering any other car.

 

[PokerBroker]

I like that Musk pre-announces things; I just wish the announcements set more appropriate expectations. Meeting expectations is the key to consumer satisfaction.

I'll take Elon's approach over the other OEMs practice of announcing developments for 2020 and concept cars that never see the light of day, all while rolling out same-as-last-year cars with zero innovative technology year after year. The auto industry is one of the worst at innovation. by the time new tech makes its way into cars it has been mainstream in other devices for a decade. None of it is original to the auto makers eg Bluetooth, touchscreen, etc.

 

[JRP3]

- The thermal management system in the car is designed to work in conjunction with supercharging. Many Model S owners have experienced the TMS operating at maximum during a supercharger session, which makes sense as a known characteristic of Li-ion cells to to generate more heat when charging than discharging. It's quite possible the TMS components (compressor, evaporator coils, heat exchanger etc...) in the Roadster is not up to this task.

- The thermal cooling plumbing in the pack itself has to manage the additional load of supercharging, yet do so in a constrained space. There may be packaging issues attempting to make that work.

You bring up several good points, and I think these two may be the most significant, which I didn't even consider. When you add them all up it should be obvious to most why supercharger access is very unlikely to happen and not a good use of Tesla's engineering time.

Doug_G They had to do an updated battery for the Roadster to meet their prior commitment to provide replacement packs, because the original cells are no longer available. This is the cheapest way to do that. The fact that it is higher capacity is not just a side-effect; it is unavoidable!

They could have used fewer cells in parallel, and made a lighter pack with the same capacity as original, but the extra cells provide greater range, cycle life, and extended power output, with no additional engineering and minimal expense, so why not use them?

 

[Juanmax]

Ok, let's me put some of my previous points into perspective.

What they are doing is meeting an obligation by sourcing a battery to replace obsolete tech to those who bought the battery replacement option. To choose to do anything else would have meant additional engineering time, time that would take away from advancing their current product line (cost of lost opportunity).

Hopefully this helps you also understand my comment of 'the market just isn't there'. It isn't. No sane company would put engineering time into providing new tech and options to a market that is not only small, but will become smaller over time (unfortunately). There is no hope of market growth in this particular case.

As already commented, Tesla did not need to increase the range to 400miles, this is a marketing number which forced them to look into further optimizations to achieve it. My god, they even went into wheel bearings with less drag! So, the 400km mark benefits Tesla from the marketing point of view. We will see once the price is set, if the Roadster owners also benefit from it, or it is so overpriced that only few of us will buy it.

As Elon says, Tesla has simply not the cash to spend in typical OEM big publicity, the better they have is us Tesla drivers and enthusiasts. The Roadster is a halo car, which grabs eyes where it drives, people ask, you start telling them how nice EV driving is, blablabla, and then comes the $1M Question: Range> tick. Second Q: Charging times> "Ummm, you know, Tesla is bulding this SC network and...", and then they ask, "Ok so you can use this forever for free?". Now it is the bitter answer: "No, the Roadster can not use this network" , "How come?" :redface:

I am not requesting anything nor complaining, just trying to explain my perception of the added value of SC. IMHO, Tesla has currently two major winning points over other OEMs.
- Range
- Supercharger network

The earlier will decrease its competivity within the next years. SC, however is the real game changer. In Europe much more important than in the US! Here is a nightmare to cross region borders with an EV (different energy suppliers for the chargers). Imagine crossing three/four countries !

Tesla, same as all other auto manufacturers, is in the business of selling NEW cars and has ZERO obligation to invest any money into old models aside from keeping them running during warranty and providing for parts thereafter. Any investment of time and resources into a car that has already been sold is at a loss and those dollars are much better invested into future products. Tesla is only obligated to make an original spec battery available to us and no more. Everything else they have done is a blessing whether you think they have gone far enough or not. Even if supercharging was possible it would be a losing proposition for them to invest into making it happen. This complaining is getting absurd. It is like saying that Apple should upgrade the battery and lightning adaptor in your old iPhone so it has current technology... No, buy a new one.

Again, Tesla won't earn any big money on this updates, of course, but it would have done much to the firm reputation to their Roadster owners. See it as marketing investment and not as a loss.

Comparing an Iphone with a Roadster is not exactly brilliant. "Buy a new one..." you say? First, there is no NEW Tesla Roadster. Second, we are talking about some more zeros in the price tag. Third, there are old iPhone lighting adapters.

I am very happy :love: with my car and not complaining at all, wishes are just wishes, and I reckon the SC capability is a doable realistic improvement (in comparison with other unicorn-like upgrade wishes: AWD, liquid cooled PEM/Motor...)

 

[bonnie]

Ok, let's me put some of my previous points into perspective.



As already commented, Tesla did not need to increase the range to 400miles, this is a marketing number which forced them to look into further optimizations to achieve it.

No, it is an Elon-number & my belief is that engineering scrambled to meet that number, so Elon would not have to back track. (And that's a whole 'nuther discussion.)

 

[ecarfan]

@Juanmax,

Yes, adding Supercharging to the Roadster is "doable", as you say (almost anything is "doable" if you throw enough money at it), but it is not "realistic" in my opinion. The possible gains to Tesla of doing that are outweighed by the significant engineering resources required, the likely very high cost that an owner would have to pay to have their Roadster converted, and therefore the very limited number of owners (out of the approximately 2,400 currently driving a Roadster, a tiny number in the world of automobiles) who would decide to do it; and with that tiny trunk most owners don't do lengthy road trips, though of course a few do. The result would be that very few Roadsters would be modified for Supercharging and the vast majority of owners would still be telling people interested in their car and in EVs that their Roadster can't use the Supercharger network, it's for the Model S/X cars. Which I find people understand when I lay out the Tesla timeline of model development and explain how the Roadster was a limited production "proof of concept" vehicle.

 

[Juanmax]

The possible gains to Tesla of doing that are outweighed by the significant engineering resources required
...
Which I find people understand when I lay out the Tesla timeline of model development and explain how the Roadster was a limited production "proof of concept" vehicle.

To 1: With little man-help if at all (but the required tools and information) I am pretty confident I could modify a Roadster to allow SC within a month. Hear that Tesla? I am open for everything & you know where to find me

To 2: Of course, this is the long answer which is in my opinion understandable.

 

[tomsax]

Of course, producing cars far different and better than other offerings is another key to consumer satisfaction. That's why we can have so many people simultaneously complaining, and yet not considering any other car.

Brilliant observation.

Has anyone counted the number of Roadster owners complaining? What fraction is that of the total Roadster population? Or even just the fraction of Roadster owners on TMC?

Personally, I'll bet most owners think, "sounds nice, how much does it cost?"

 

[Jaff]

Agree 100% !

Brilliant observation.

Has anyone counted the number of Roadster owners complaining? What fraction is that of the total Roadster population? Or even just the fraction of Roadster owners on TMC?

Personally, I'll bet most owners think, "sounds nice, how much does it cost?"

 

[bonnie]

Personally, I'll bet most owners think, "sounds nice, how much does it cost?"

It's like you're in my head. Stop that!