400 Mile Pack (Was New Roadster Goodies for 2014) I do not believe your "fact" is actually a fact. That is not what Elon's tweets said. One tweet said that tomorrow he would release details on the Roadster battery upgrade. The other tweet said that in the future there will of course be an "upgrade" for the Model S battery. Two separate tweets on separate subjects. The Roadater battery upgrade was not a necessary first step before a Model S battery upgrade could occur: upgrades to the S battery were always envisioned. You seem to be linking them in a way that I do not think he intended. In my opinion.
We'll see tomorrow when they make the announcement. It's possible that the next gen chemistry is ready, but they don't have mass production in place to supply Model S. A limited field trial with the Roadster would give them data over a larger sample set than available in the lab or on test mules.
Again, please tell me what extra data Roadster owners can give? Remember Tesla can test new cells at temperature extremes and voltage extremes that Roadster software will not allow. Tesla can run packs up to 4.5V per cell or whatever they want, at 200 F, or down to 1V per cell, at minus 50 F. They can do this in the lab and in the real world in cars with tweaked software. There is nothing that a few months of Roadster drivers can offer Tesla that's more extreme than what Tesla can do. If a new chemistry is available in limited production and they are confident enough to offer it to Roadster owners then all testing is done and they are not looking for any more data from Roadster owners.
I certainly have no desire to be a Tesla guinea pig and I highly doubt this is what they have planned. Model S cells it is.
Since it's my belief that Elon's original announcement about the battery upgrade was a surprise to the engineering team, I'd be hard pressed to believe then that upgrading the battery with new tech cells was part of a master plan to gather data from Roadster owners. if the announcement is 'free to all over the next few months', then maybe - a case could be made that they were trying to get the new tech out there, quickly, to as many Roadsters as possible. But if the announcement is including pricing details & people buy when they're ready for a new battery? Nah. Model S cells.
He's once again reinforced the SF to LA claim. The Model S cells just fall short at real world speed. My money is on next gen cells.
That's a critical point. Even assuming the 245 miles EPA for the Roadster, you get ~360 miles of range with a direct Model S cell swap, which is just a bit short of the SF to LA trip (which is more like 380 miles).
Yes, 'simple math' does not enable LA-SF route (380+ miles). There must be a little bit more that just cell replacement or we do not have all the details. Maybe these newer cells are more efficient at average highway power draw? So same capacity, longer HW range. Maybe these newer cells are a bit lower weight so they can pack more? They wouldn't want to change total weight to much. Maybe these newer cells need "less outside protection" i.e. thinner walls so they can pack more into same space/weight? Maybe these newer cells can be charged a bit higher and discharged a bit lower? This would be accounted for in nominal capacity though. Maybe 85kWh is just a marketing term, just a good name for the big battery and it's exact total available capacity is a) higher and b) changes over time My bet? No clue...
Maybe Elon is being disingenuous because you could do the trip non-stop now at 10 mph. But I doubt it. We know from previous specs that the 3.4Ah are in fact ever so slightly heavier but not enough to make a difference. I barely notice range difference from extra mass at highway speeds, as you would expect. I reckon Tesla have early samples of the next gen cell now and the pack availability will coincide with the start of production proper.
This looks ever more probable. It also explains why Elon 'had to' comment on Model S not getting a bigger battery soon. I bet it will get it together with MX launch. No sense in launching MX in 2015 with a battery tech from 2012.
What about the same cells as in the E pack, that have arrived on the new Model S? (Not just P85D) Anyone sure if this pack have the same chemistry as the A,B or D packs? If Tesla have cut pounds on the pack over time (better kW/kg), gained more power withdraw to support the P85D, this would benefitt the Roadster as well.
David - Do you have any info on these next gen 18650 cells that you can share? Everyone - 3400 mAh cells would be a nice upgrade for the Roadster, but it seems unlikely that Elon would claim "400 miles" and "LA to SF on one charge" with 6831 of those. 4000 mAh would provide that sort of range, so they are a possibility. GSP PS. Don't forget that the Roadster pack was designed with two safety cut offs built into every cell. This means that replacement cells most likely will use the same can, not the Model S can. Therefore I think using the latest production (NOT experimental) laptop cells (like the orginal Roadster pack) is the most expedient design option.
I like to think that this pack upgrade is part of some field testing for model 3 hardware/firmware. Maybe a pack coolant flow arrangement or some BMS protocols. Or maybe it's Model IV related.
I do not agree 100% on that. Vehicle integration and validation tries to test extreme real world conditions with controlled scenarios, it is however very difficult to find out possible issues in rare use-cases. Every major OEM and tier 1 supplier have run thousands of test rig hours and you still see callbacks and non-typical failure rates at any given component/system. From my point of view, some Roadster owners can provide more (different) information than a small fleet of test cars.
On my phone at the moment, so only this Panasonic Develops High-Capacity Lithium-Ion Battery Cells That Can Power Laptops and Electric Vehicles | Headquarters News | Panasonic Global There is a much more up to date presentation with many more details out there. I have it on my laptop and will post later but it's public domain.
Exactly. Unit testing and integration testing can be done in a lab or on test mules, but some types of data can only be seen in a large sample set. For example mean time to failure of individual cells can't be measured with a small batch of cells, you need to observe thousands of them to catch a couple dying. Similar to Elon's comment that the production problems in the Model S weren't apparent until they started making thousands of them. Doing a ramp up with the Roadster would be extremely valuable for them - the Roadster already phones home with log files, so why not use that data? It'll be interesting to see the capacity of the new pack. Anything over 82kWh would imply new chemistry.
Tracked it down http://www.embedded-world.eu/fileadmin/user_upload/pdf/batterie2011/Sonnemann_Panasonic.pdf
then dont upgrade and dont ever buy a new model car. - - - Updated - - - and hence no need for recalls ever. battery fires were totally anticipated by testing according to your assertion that road testing not needed. titanium shield only added after many cars were on the road already.
Theory... So Tesla has this better battery chemistry that has better energy density and lower cost. They are currently testing that new chemistry with a few cars. They know what they know, and they know what they don't know. They need more data to fill in those blanks. This new chemistry isn't available in production scales to take over Model S production (and won't for a few years). So what might be a good idea ? Retrofit this newer/advanced battery pack to the Roadster (limited demand, deeper pocket customers, oldest packs currently=highest benefit possible). This wouldn't be an experimental pack no more than the first generation Model S pack was/wasn't experimental. The critical safety tests will be done prior to releasing this to the public, but there's nothing like random customers doing random things to accelerate data gathering once all planned tests are accomplished and limited normal driving took place. My theory is Tesla will announce this new pack for 6 months from now, with the unplanned possibility of issues that could delay this to late 2015. Its a win/win/win. Roadster users willing to pay for it get 400 mile range. Tesla gets essential data that is essential before rolling this new chemistry as a default for Model S / Model X / Gen III. They probably expect the Giga Factory to startup only producing this newer chemistry from day one, so they need to be positive the battery is better in every respect over the old one. Just a Theory. Things one can theorize with the limited information available. Tesla won't put a potentially unsafe battery pack on the market. But even if its safe it doesn't mean Tesla knows everything there is to know about it. But there are MANY shades of gray from an unsafe prototype to a 100.00% tested battery pack.
None of which told Tesla anything new about the cell chemistry in the Model S. If Tesla started offering new Roadster packs today they would not get any significant mileage from anyone to tell them anything they don't already know before they need to start putting new cells in the Model X. How many Roadster owners do you think are really going to put 30,000+ miles on their new packs in the next 6 months? I'd say a safe bet is less than 2, if any. You think that's a significant data set for Tesla? More likely the Roadster packs won't be available until well into 2015, about the same time the X will roll out. If the X is indeed getting upgraded cells zero data will be generated from Roadsters that would be relevant. I do agree that a 3.4 ah cell is the only way to make the claimed range without using some funky math, and that would lead me to think the packs will come later rather than sooner.