Dodge Circuit EV (Lotus Europa conversion)

[Palpatine]

The cylindrical batteries that Tesla is using have a high C rating. Which as I understand it permits higher amperage discharge.

I recall Daryl Siry saying that they would never get the performance needed from the A123 chemistry. They have plenty of power density and they are long lasting. But the energy doesn't come out of them fast enough for a high performance sports car. I don't have anything technical to back up my statement. That is just what I remeber being told.

 

[TEG]

Well maybe Siry or someone more knowledgeable can chime in. My recollection was the downsides to A123 were cost and vehicle range for a given weight. Power performance was not an issue.

By the way, UQM 200kW:

(I bet that motor weighs a lot more than the Tesla motor)

I think the Dodge circuit prototypes carry an onboard charger (more weight, no reductive) and offer only 1/2 the pack capacity (26kWh vs Tesla's 52kWh) so would likely end up with of a range of about ~<150 miles, not ~240 like the Tesla.

 

[WarpedOne]

I recall Daryl Siry saying that they would never get the performance needed from the A123 chemistry. They have plenty of power density and they are long lasting. But the energy doesn't come out of them fast enough for a high performance sports car. I don't have anything technical to back up my statement. That is just what I remeber being told.

There is some misunderstdanging in there:
Power density = speed of energy comming out per weight or volume => watts per kg or Watts per litre
Energy density = amount of energy per weight or volume => kWh per kg or kWh per litre

A123s can output lots of power (they are rated at 30C constnat discharge, and up to 50C spikes) while tesla's battery can only go up to 4C max. They have about 10 times less power than A123 so Tesla needed about 10 times as many for same power output. But on the other hand, Tesla's battery have higher energy density, they hold more energy.

Tesla was able to squize 53kWh of energy into 900 pound pack. If they've used A123's that number and hence range would be considerably lower.

The other problem is availability. A123s cost an arm and a leg and there is only one maker. If it sinks, Tesla would sink with them. Tesla is thus using standard batteries in 18650 format that have many makers, if one sinks, they could easily switch to another maker.

 

[TEG]

So, WarpedOne confirms my recollection.

I guess the operative word is "performance". Someone could use the term performance to talk about range, not just 0-60.

Or another way to put it - if they put enough A123s to get the 'required' range (e.g.: 240+ miles) then the cost 'performance' wouldn't be good, and the 0-60 'performance' would be hampered by all the weight.

ENVI seems to have accepted reduced range as a compromise. With some more engineering work (weight reductions, inverter improvements) they might be able to meet Tesla's 0-60, but I don't think they will be able to outdo the Roadster on price if they try to meet its' range.

 

[JRP3]

The question I have regarding energy density is how much density is lost in the spaces between cylindrical cells compared to prismatics? So we know a Tesla commodity cell has 2.4 ah and the same sized A123 has maybe 1.6 ah(?)
but once you start packing them together what is the density of the same volume of A123 prismatics? Also less volume taken up with cooling and management for the prismatics I would think.

 

[TEG]

Yeah, I gather there is some of that, but not enough to make up the difference.

 

[graham]

The biggest missing piece in this is not the precise details of each technology, but the reasons behind why Tesla chose the technology they did. Tesla used the best / most cost effective technology available to them at the time. They used consumer electronics batteries instead of either waiting for/funding someone to make an affordable car battery, or trying to design their own battery.

This means that not only did Tesla get a huge jump on the rest of the industry, but the development R&D costs for the batteries were already paid for (although admittedly not the charge controller / cooling). GM, Chrysler etc did not do this, so they have to wait a very long time for the battery tech to be developed, as well as pay a relatively high cost for the batteries when they finally come.

To compare their expensive, lower performing forthcoming product to Tesla's existing product is to assume Tesla will not continue to improve between now and when Chrysler's product is released.

 

[Palpatine]

I think Elon once mentioned that the ideal cell for a car application would be about 4x larger than the commodity cells that Tesla is purchasing now. Also, the case that each battery comes in weighs too much. They could dramatically reduce the weight of the complete battery pack if they could get some changes made.

But then it wouldn't be a commodity battery. It would be custom designed for Tesla Motors and would likely cost more.

 

[JRP3]

To compare their expensive, lower performing forthcoming product to Tesla's existing product is to assume Tesla will not continue to improve between now and when Chrysler's product is released.

Another important aspect to consider is the A123 cells will likely last much longer than the Tesla cells, which reduces cost of ownership in the long run.
With the high output capability of the A123 cells they could potentially outperform the Roadster in acceleration in a similar weight vehicle. Remember Killacycle uses A123 cells to be the fastest EV drag bike in the world.

 

[vfx]

In the interview I believe Elon pointed out that a cell is a cell. More than one cell in a form is a battery. So you have a big box called a battery (modular or not) that holds a bunch of cells. Tesla's take starts to sound even more versatile because they can do the low profile pan of the Model S or make odd shapes like the Roadster or Smart. Much more modular.

 

[vfx]

Also, the case that each battery comes in weighs too much. They could dramatically reduce the weight of the complete battery pack if they could get some changes made.

I do remember that. Switch to aluminum or something not steel.

 

[walk_n_wind]

End of this thread?

Hmmm...sounds like this Dodge EV is soon to be over with?

Jalopnik - Dodge Pulls Plug On Circuit EV Electric Sports Car? - Dodge Circuit EV

 

[vfx]

Is it
walk and wind
or is it
walk n wind?

 

[walk_n_wind]

Thanks for asking!

It's walk and wind (long 'i') - you know, like an automatic watch?

 

[vfx]

It's walk and wind (long 'i') - you know, like an automatic watch?

Wasn't sure if you had a turbine on your roof.

This might work:

walk n wind n drive

 

[TEG]

Or with more wind...

 

[TEG]

FYI, the UQM motors tend to have a much lower redline than the Tesla motor.
(e.g.: 5,000 RPM vs 13,500 RPM)

(A UQM spec sheet here)

Because of that it would need much taller gearing to reach a useful top speed. Further reason why it could have an acceleration performance shortcoming compared to the Roadster.

 

[dpeilow]

Hmmm...sounds like this Dodge EV is soon to be over with?

Jalopnik - Dodge Pulls Plug On Circuit EV Electric Sports Car? - Dodge Circuit EV

Hmm, Jalopnik really does use a lot of past tense in that article. They seem pretty sure.

 

[domenick]

Doug already posted the ABG take on this. Sam actually talked to people involved instead of just repeating someone else's mistake.

REPORT: Dodge Circuit DOA? Not according to Chrysler - ABG

That's not to say it shouldn't be killed and make one of these with an electric drivetrain. Interestingly, they were showing this 2005 concept at the recently-held Denver Auto Show.

 

[SirGiles]

Tesla / lotus with a Dodge badge?

Looks very much like a Tesla / lotus with a Dodge badge?


Anybody agree?

YouTube - Dodge Circuit Drive