New Roadster Goodies for 2014

[Jackyche]

Isn't the Nissan Leaf replacement pack $5500? That ratio would yield $22,000.

And since Elon said Gigafactory will provide AT LEAST 30% cost savings, we're looking at $15,400.

I'll probably shell out $15,000 for the pack. Even though I don't need it. At all.

Are there any projections on price? With Nissan saying a new 24 kwh pack will be $6200 using an approximate ratio for a 96 kwh pack would be $24,800. It would be nice if the Tesla cost were to be a little less. 96 kwh should be close to 400 miles.

 

[JST]

Are there any projections on price? With Nissan saying a new 24 kwh pack will be $6200 using an approximate ratio for a 96 kwh pack would be $24,800. It would be nice if the Tesla cost were to be a little less. 96 kwh should be close to 400 miles.

Note I believe the price includes labor and installation. And personally not sure I want to install a 1000lb battery myself anyway.

Nissan has since said that they are losing money at that price.

 

[ChadS]

I don’t think I am posting anything new here; I am just trying to summarize some of the speculation so far.

We are missing some key details such as exactly what cells Tesla will use and their specs and price, and how much Tesla will charge for the new pack. Those details could change everything; see below for more on “unknowns”. But from what we do know and guesses we have made, it looks like the ~400-mile (likely not really that much) pack upgrade accomplishes the following for Tesla:

1. Fulfills promise to make replacement packs. Tesla already pre-sold some pack replacements, and they have to use new cells to rebuild failing packs when they run out of good-enough old cells anyway (though I don’t know how close they are to that point; see “unknowns” below). They are already committed to the engineering costs of getting a replacement out, so that cost is sunk - though the amount is variable, see next point.
2. Minimizes engineering costs. There are only so many Roadsters, and not all will get a replacement pack. So this will be a low-volume operation. That means the engineering cost will not be spread over many units, so keeping the engineering costs (including time – opportunity cost is key with Tesla engineering!) low is important. If this pack really just replaces existing cells in the existing pack and uses the same number of cells, this could be the lowest-engineering-cost plan possible. Reducing cell count may require wiring, fusing and/or software changes.
3. Allows field testing. Tesla will almost certainly want to use these cells in other products in the future (when they are cheaper). Rolling out a couple of them at a time to early-adopter Roadster owners is a great way to field-test small quantities of them.
4. Uses expensive cells in the most-appropriate application. High per-unit part costs are never good, but they are easier to justify in low-volume high-priced applications – just like Tesla used carbon fiber for the Roadster, aluminum for the Model S, and likely steel for the Model 3. If you are going to use really expensive cells somewhere (and there are several potential reasons for that) the replacement Roadster pack may make more sense than their other options.
5. Gains EV converts. The mere existence of a 400-mile pack (even if few buy it and even fewer use it with any frequency) is going to go a long way towards quieting EV doubters and making consumers demand better plug-in offerings from other automakers. 0-60 and handling improvements could grab some attention too, but potential Model 3 buyers would be less likely to think that would apply to them; and it would require more expensive and less practical tires, suspension changes and who knows what other work. Of course, the large pack will be an order of magnitude more effective if it is also affordable. Given the low volumes and cutting-edge cell specs, it will likely cost Tesla a lot to make them, so it will be very interesting to see how they price it to the customer. Most owners don’t need it yet; I wonder if they will offer a reduced-cost pre-buy option.
6. Improves high-end performance. My understanding is that the Roadster is largely traction limited until roughly 50mph. I suspect the pack weight will be similar, so I don’t think low-end acceleration will change. But I believe the Roadster is power limited above that. We don’t know the cell specs, but with a significantly larger pack, more power is possible (I hope the PEM and motor can handle it if so. Power might not be higher if power density is lower; that might reduce costs instead). There will not likely be better cooling, but the larger, new-formula pack might (?) give off less heat. High-end performance may improve.
7. Improves usage and reliability. A larger pack means longer life from less cycling, and less damage from high-speed driving and charging. You also get more buffer on trips, and fewer issues if you forget to plug it in or charging is interrupted, etc.
8. Reduces clamoring for Supercharger access. A larger pack could also mean faster charging – like Supercharging – though it seems that is too much to hope for since other expensive bits would have to change and Roadster owners didn’t pay for Supercharger buildout. However, 400 miles means Supercharging is less likely to be necessary to complete trips. You can still fill it overnight on an HPC.
9. Raises Roadster resale values (may echo on other Tesla models). An available replacement pack – especially one that means an improvement in range and (perhaps) high-end speed – will likely raise Roadster resale values and send a good signal about future prospects to potential customers. At least if it is priced reasonably. That could also help banks predict higher future values for other models, which could reduce lease rates.

Downsides to the ~400-mile pack plan:

1. Cost. While there are many details we don’t know (see below) there is no doubt that the per-pack cell cost is going to be very high (it sounds like at least they can reuse all the old packaging – but at a significant labor cost). If the price they charge customers is commensurate with the cell cost, many Roadster owners are going to be very unhappy spending more on a replacement battery than the rest of the car is worth (we can look forward to a 50-page thread complaining about it here), and potential Model 3 customers will be frightened by the costs. If they charge considerably less, owners and potentials may be happy but Tesla could bleed money on a discontinued product line and the TSLA shorts will have a field day.
2. No weight improvement. Many owners (including me) don’t need 400 miles of range. They are happy with the range they have and would much prefer a lighter pack for better acceleration and handling and less tire wear - and ideally smaller physically so there is more storage space. It doesn’t look like this plan is likely to deliver any of that. (A significantly lighter battery might be hard to deliver if it means another round of crash tests. I know that crash testing is required for new model offerings but not for later third-party upgrades; I am not sure about OEM upgrades).

Unknowns that could affect how we look at this:

1. Cell details. Cost, energy and power density, cycle life, heat production and tolerance, etc.
2. Cell availability. Part of the reason I didn’t expect the "2014 Roadster surprise" to be a 400-mile pack is that Tesla says their production is cell limited, so why would they throw a bunch of cells at an old product? But it might be that these new cells come from a completely different line, so there is no opportunity cost given that Tesla is not going to use them in another product (yet).
3. The actual EPA rating for the new pack. I don’t think we really expect it to be 400; but we hope it will be close.
4. Price! This will determine how owners feel about the offering, how many get purchased, and how potential Tesla customers feel their car will be supported when they need/want a new battery. Even if Tesla just charges at part cost, I fear almost nobody will buy one and potential customers will be frightened (though I am guessing as I don’t know the actual cost). A subsidy may be necessary but I’m sure Tesla wants to avoid more of that than necessary.
5. How Tesla will treat people that pre-bought a battery replacement – will they get the larger size gratis, or have to pay extra? If they don’t pay extra, do they get the same pack with a software-limited range like the 40kWh Model S? (When I bought my Roadster, I thought the pre-purchase option sounded like a good deal...but frankly, in July 2009 it was not at all clear that Tesla was going to be around long enough to deliver the car I had to pay cash in advance for, much less long enough to build replacement packs. Spending more than necessary didn't seem like a good choice then, though now of course I wish I had. Actually, another reservation I had was that the contract only allowed for a pack of similar capacity, and I wondered if I might prefer to buy a different one if available...something we still don't know!).
6. How many old cells are available. Do they have enough in good shape that they can continue to repair and replace packs for several years? Or are they running out of good cells? Or do they have another pressing use for the cells (like at Superchargers).

My summary:

This solution isn’t everything that every Roadster owner wants. For example, I’d sure prefer a cheaper, lighter pack. But if they navigate the pricing issue correctly (I'm worried about that part), this could be a really good solution for Tesla overall – it fulfills their promises to Roadster owners, raises used Tesla values, helps interest new people in EVs and helps embarrass other automakers in to upgrading their offerings. All without taking much engineering time. And hey, some owners will be very pleased with the extra range.

The price and how it is perceived by owners and potential customers is the largest open issue by far. That will be key to determine how well this solution meets Tesla’s goals - if it's overpriced nobody will buy it, resale values could go down and lease rates up, potential customers could be scared away and EV haters would have that high replacement cost to latch on to. I think Tesla’s goals are best met by applying some subsidy (though it’s hard to be sure without knowing more about costs). That would likely please Roadster owners as well. :smile: Tesla doesn't "owe" it to Roadster owners but I think it should be seen as a reasonable marketing expense - the effects of the pricing will go way beyond Roadster owners.

 

[JRP3]

I'd love to see this be available from OEM or aftermarket, but I don't see the aftermarket getting into it unfortunately.

I'd expect the aftermarket to do it before Tesla. There are a number of high C rate cell options for those more concerned with power than range. Anyone want to try some 90 C rate li poly?

 

[richkae]

I'd expect the aftermarket to do it before Tesla. There are a number of high C rate cell options for those more concerned with power than range. Anyone want to try some 90 C rate li poly?

If I could magically swap in a pack that cut my range in half ( in the 25 to 30 kWh range and produce the same or a little more power so that you spend less time battery limited ) that would shave 500 pounds off the Roadster I would do it in a heartbeat.
How much does 25kWh of LiPoly weigh?
Since I have a Model S for long distance driving - the Roadster is now my toy, and I rarely need more than 100 miles range.
If it was 500 pounds lighter it would be immensely more fun at the racetrack.

How much would I pay to do that? Not sure.

 

[JRP3]

One example of a high C rate li poly: http://www.hobbyking.com/hobbyking/store/__18208__turnigy_nano_tech_1300mah_4s_45_90c_lipo_pack.html

 

[spaceballs]

One example of a high C rate li poly: http://www.hobbyking.com/hobbyking/store/__18208__turnigy_nano_tech_1300mah_4s_45_90c_lipo_pack.html

Lets crunch some numbers with these high rate C packs.

high rate C pack is 14.8v with peak of 117 amps, capacity is 1.3ah.

Existing ESS max peak (over estimated for safety margin): 500 Amps @ 400v.

400v/14.8v = Need 27 packs to meet the voltage requirements.
500A/117A = Need 4.2 (lets round up to 5) packs to meet the Amps requirements.

So 27*5 = 135 packs needed, in 27S5P configuration, Cost be $2,504.25 per hobby king website.

High rate C pack 0.342 pounds each, so that's 46.17 pounds just for the batteries.

1.3ah * 14.8v = 19.24 watt hour, so 135 of them is 2.597 KWh.

Roadster gets what 300WH a mile? that be 8.6 miles.

That be a Fun 8.6 miles though

*note forgive any math errors, I didn't double check them.

 

[adiggs]

Lets crunch some numbers with these high rate C packs.

high rate C pack is 14.8v with peak of 117 amps, capacity is 1.3ah.

Existing ESS max peak (over estimated for safety margin): 500 Amps @ 400v.

400v/14.8v = Need 27 packs to meet the voltage requirements.
500A/117A = Need 4.2 (lets round up to 5) packs to meet the Amps requirements.

So 27*5 = 135 packs needed, in 27S5P configuration, Cost be $2,504.25 per hobby king website.

High rate C pack 0.342 pounds each, so that's 46.17 pounds just for the batteries.

1.3ah * 14.8v = 19.24 watt hour, so 135 of them is 2.597 KWh.

Roadster gets what 300WH a mile? that be 8.6 miles.

That be a Fun 8.6 miles though

*note forgive any math errors, I didn't double check them.

Think of the range anxiety. You'd barely get around the block, before you'd start worrying about whether you're getting home or not

 

[spaceballs]

Think of the range anxiety. You'd barely get around the block, before you'd start worrying about whether you're getting home or not

Well this is the absolute minimum to keep 100% power and voltage the same as the ESS. From there I would keep adding strings of 27 packs (at ~$500 increments) until you get the desired range wanted

 

[WarpedOne]

ChadS:

I don’t think I am posting anything new here ...

Nice wrap up.
I feel we can be more certain on what cells they are going to use - because of keeping the cost down they will use the cells they are already using in MS or are about to start using "en masse" so they don't pay the whole price on those few millions (gulp) cells as they will be taken out of a much bigger shipping with lower total price per unit. They might not be exactly the same simply because current cells are not exactly the same as last year's cells. They are going through continuous improvements, including minor change in capacity.

If they are working on a bigger pack for MX (and then also MS) they might use those newer cells but they would need to charge about $40k for such a pack. At 15k(?) prepaid plan they would loose about $20k on each single pack. Ouch! Bad bad bad management.

They might use what they are using now and is available to them at lowest cost - maybe even use some cells out of failed MS packs that are not suitable for rebuilding a 60kWh pack out of 6216 such cells but are still alive and well - only with some lost capacity.
This could result in bad publicity and also I don't see who would tear apart all those used packs and reconfigure the cells into Roadster pack configuration. To much manual labor.

Roadster uses 8,8Wh cells (56k / 6831) . For ~400mile range, they'd need about 2/3 higher capacity cells at same weight - about 14Wh cells.
MS uses 12Wh cells from about 2010. 7% annual capacity improvements (at same cost and weight) results in 15Wh cells today. This would be 106kWh pack for MS and MX and ~102kWh pack for roadster at same weight.

So, basically there are two options
a) a 400 mile pack out of new 15Wh cells for ~$40k
b) a 360 mile pack at prepaid cost build out of "old" and current 12Wh MS cells

I can clearly see it now: those 400 miles is only 350 EPA miles. They will use current MS cells and offer the pack at prepaid cost.

 

[FANGO]

If I could magically swap in a pack that cut my range in half ( in the 25 to 30 kWh range and produce the same or a little more power so that you spend less time battery limited ) that would shave 500 pounds off the Roadster I would do it in a heartbeat.
How much does 25kWh of LiPoly weigh?
Since I have a Model S for long distance driving - the Roadster is now my toy, and I rarely need more than 100 miles range.
If it was 500 pounds lighter it would be immensely more fun at the racetrack.

How much would I pay to do that? Not sure.

I would do the same thing in a heartbeat, and I don't even have another car.

Also, if we're talking Li poly and new cells, it would certainly be more than 50% weight savings for 50% energy reduction. Realistically you could get half the pack weight and still have maybe 80% or more of current energy storage using new tech.

- - - Updated - - -

If they are working on a bigger pack for MX (and then also MS) they might use those newer cells but they would need to charge about $40k for such a pack. At 15k(?) prepaid plan they would loose about $20k on each single pack. Ouch! Bad bad bad management.

A 400 mile pack will almost certainly cost ~$40k. They may give a discount for turning in your old Roadster battery. Whoever else was saying a new Roadster pack will cost $15k was dreaming, this won't happen as much as any of us would like it to. And the quoted 30% gigafactory cost reduction includes the natural cost reduction of cells over time, so you can't just shave 30% off of the price of something, because that's already been taken into account when talking about the availability of current higher-tech cells at similar prices to older lower-tech cells.

As for prepaid packs, it was 12k I believe, but remember the time value of money. Tesla received that 12k when it wasn't even public yet. Since then, the company has gone up well over 1000% in market cap. 12k then is worth a LOT more than 12k now, and that was the intent all along - to provide early capital for Tesla, and to give risk-averse owners a safety blanket. So giving out a new pack wouldn't be a bad economic decision by Tesla - still, though, I feel like they will give people who have that plan a credit for the energy equivalent of the current Roadster packs, and then charge for the excess.

 

[Matias]

Lets crunch some numbers with these high rate C packs.

high rate C pack is 14.8v with peak of 117 amps, capacity is 1.3ah.

Existing ESS max peak (over estimated for safety margin): 500 Amps @ 400v.

400v/14.8v = Need 27 packs to meet the voltage requirements.
500A/117A = Need 4.2 (lets round up to 5) packs to meet the Amps requirements.

So 27*5 = 135 packs needed, in 27S5P configuration, Cost be $2,504.25 per hobby king website.

High rate C pack 0.342 pounds each, so that's 46.17 pounds just for the batteries.

1.3ah * 14.8v = 19.24 watt hour, so 135 of them is 2.597 KWh.

Roadster gets what 300WH a mile? that be 8.6 miles.

That be a Fun 8.6 miles though

*note forgive any math errors, I didn't double check them.

On the other hand. If you would create Tesla Model S pack. 85 000Wh/19.24 watt hour = 4418 cells. They would cost 59819 euros.

But you would have 90 C peak discharge (7650Kw=10 000hp) and 10C rate charging, so full charge in 6 minutes, if my math is correct! I'm pretty sure there would be some markets for 10 000 hp sedan :biggrin:

Heck, this car would make Bugatti Veyron look like golf car!

Though off the shelf 500 kW motor seems to weight over 2000kg so my plans still needs small refinements :tongue:

At least you could use two Model S performance 476 hp motors and get 952 hp! Bugatti Veyron costs over one million euros, I'm pretty sure Tesla could sell 952 hp Super Tesla cheaper than that.

 

[Doug_G]

Roadster gets what 300WH a mile?

No, that's the Model S number. Roadster is something like 200-ish.

 

[thefortunes]

No, that's the Model S number. Roadster is something like 200-ish.

In my 25k miles of ownership I am averaging 256 Wh/mi, with a daily high of 477 (pretty spirited day:biggrin and a low of 177.

 

[lmore]

For making a battery for the Roadster, were to get the documentation needed?
I discussed with an electrical engineer which asked:
"Could anyone schematic diagram of the current PEM? It seems to me that if you change battery properties, we'll have to modify the PEM?"
Perhaps the battery pack could simulate battery pack sensors etc. so the PEM does not need to be changed a lot. I remember reading somewhere that the Roadster battery pack is "stupid" compared to the Model S battery pack which has more features.

What was the problem that needed repair?

The Roadster suddenly stopped and would not drive anymore, I think I reported the error messages on this forum when it happened. Probably a tantal condenser blew and caused some other components to die as well, I noticed a tantal condenser were burnt otherwise there was nothing wrong to see. We replaced some components and the car was running again.

 

[JRP3]

If your pack voltage is in a similar range to the existing pack, nothing should need to be changed. You might need to spoof the battery management system with a smaller pack because of missing modules.

 

[chickensevil]

So I am pulling something over here from the Earnings Call that just happened, where the discussion of weight vs range was brought up. Elon said that from the first S they made to the ones coming off the line right now, there has been a weight reduction of around 200 lbs. So, you can safely say that lower weight is not going to be the key factor in hitting 400 miles on the Roadster, although 200lb's would be a larger percentage for the roadster than the S, I still think that is an interesting data point.

 

[FANGO]

So I am pulling something over here from the Earnings Call that just happened, where the discussion of weight vs range was brought up. Elon said that from the first S they made to the ones coming off the line right now, there has been a weight reduction of around 200 lbs. So, you can safely say that lower weight is not going to be the key factor in hitting 400 miles on the Roadster, although 200lb's would be a larger percentage for the roadster than the S, I still think that is an interesting data point.

Seems to suggest that crash testing would not be required for weight reductions.

 

[chickensevil]

Seems to suggest that crash testing would not be required for weight reductions.

That too. Would be interesting to pull a data point by having two Model S do some drag races or compare dyno results side by side, and early sig car and a current production car that just came off the line and see if there is any improvement in the speed and power of the car since it is 200lb's lighter. I would also have the same driver take them both around the track and see what happens

This is likely easier to get a good data point from than sorting through all of it on a roadster... since there isn't any easy way to just shed 200lb's on a roadster.

 

[JRP3]

Seems to suggest that crash testing would not be required for weight reductions.

My understanding is that about a 200lb difference does not require new crash testing, so they may still be within specs. That's the reason that the 60 is not more than 180lbs lighter than the 85, even though it should be.