Third Party Roadster Pack?

[ElectricLove]

LG Chem must be doing something right with their batteries. They've been stacking up battery wins with tons of upcoming electric cars (prismatic cells).

Here's a review of the LG HG2 cell (assuming this is the cell they would use)
LG HG2 Review (20A, 3000mAh) 18650 Battery | BATTERY BRO

In small lots, you can buy the cells for $4.50 a piece
LG 18650 Hg2 3000mah 18650 50 Pack (wholesale) - Luna Cycle

I would guess that Tesla would get a much cheaper price than that due to their buying in large volumes directly from LG. If you assume Tesla gets the cells for $3 a piece, that would be $20493 for a fresh set of cells. That would give Tesla $8500 to remove the pack and PEM, ship tnem someplace, modify the PEM, take the battery apart, remove 6831 cells, install 6831 cells, put the battery pack together, ship it back and re-install it in the car.

Without revealing trade secrets too much I'll just comment that your assumption on price Tesla would be paying for those LG cells is a bit high... Also consider this: 6831 LG HG2 cells is actually 3.7V*3Ah*6831= 75.8kwh of stored energy, seems pretty spot on to what Tesla is saying they have (ie. strong evidence that HG2 is their cell of choice)...

The next step up is actually the MJ1 cell, if they used those they would have 88.5kwh of stored energy... But the price would be about 23% higher...

If someone wants that larger MJ1 pack though, let me know, we can make it happen!

 

[asgard]

ElectricLove: What about reprogramming the software to take into account a new pack with more KWh? Do you folks have the firmware source code?

 

[ElectricLove]

That will be something we will figure out, we are very good at this sort of thing though!

This may present the type of hurdle that pushes us into offering only a smaller "performance" pack (lighter weight, similar range) in lieu of the long-range version... Tesla can (and should) "own" that space, we can focus on high performance stuff...

 

[ibcs]

Without revealing trade secrets too much I'll just comment that your assumption on price Tesla would be paying for those LG cells is a bit high... Also consider this: 6831 LG HG2 cells is actually 3.7V*3Ah*6831= 75.8kwh of stored energy, seems pretty spot on to what Tesla is saying they have (ie. strong evidence that HG2 is their cell of choice)...

The next step up is actually the MJ1 cell, if they used those they would have 88.5kwh of stored energy... But the price would be about 23% higher...

If someone wants that larger MJ1 pack though, let me know, we can make it happen!

Given those price differentials, I'm glad Tesla chose the 6831 LG cells. Adding 23% to the current price would have changed the upgrade price from 29k to almost $36k. Thanks for your insight ElectricLove, it sounds like you might be making some interesting choices for other roadster owners.

 

[asgard]

That will be something we will figure out, we are very good at this sort of thing though!

This may present the type of hurdle that pushes us into offering only a smaller "performance" pack (lighter weight, similar range) in lieu of the long-range version... Tesla can (and should) "own" that space, we can focus on high performance stuff...

Not to discourage you guys but reverse-engineering firmware and modding it without source is not trivial. If you do not have the comprehensive test suite that goes with it, running it on the vehicle is risky.
Some folks have been trying this with the now defunct Fiskar Karmas with catastrophic results. I know someone whose car completely shuts down every so often and he has to hard-reboot by disconnecting the control module from power.

I'd feel a lot more comfortable if you officially licensed it from Tesla and they might be willing to do that to a competent third-party.

 

[jeremyz]

If they store the charging parameters in global arrays instead of using #define's, it might be pretty easy to tweak the battery parameters. I was really impressed with the amount of changes people have made to the Evo's firmware. They added functionality like launch control, no lift to shift, MAF sensor support and boost control.

 

[asgard]

He evo is an entirely different beast. Third parties replaced the EMS completely and that's how it was done.
GEMS - General Engine Management Systems Ltd - Mitsubishi EVO Plug and Play EMS


The Roadster is quite different. Everything is closed source.

 

[jeremyz]

People have decrypted, disassembled and reverse engineered the EVO's stock ecu firmware. Then they added new functionality to it.
TephraMod V7 - evolutionm.net

 

[asgard]

People have decrypted, disassembled and reverse engineered the EVO's stock ecu firmware. Then they added new functionality to it.
TephraMod V7 - evolutionm.net

Firmware disassembly for the Roadster sounds like a worthwhile kickstarter project :smile:

 

[ElectricLove]

Anyone know of the name for the connector TESLA uses in the Roadster to connect to the VCU/etc (the one the OVMS uses basically)?

 

[asgard]

The CAN Bus?

 

[markwj]

Anyone know of the name for the connector TESLA uses in the Roadster to connect to the VCU/etc (the one the OVMS uses basically)?

Diagnostic port

 

[ElectricLove]

The CAN Bus?

This is the communication protocol, I mean the connector type so I can buy the adapter, I have a CAN/LIN USB communication tool but nothing to physically make the connection...

- - - Updated - - -

Diagnostic port

Beautiful, thank you so much!!!

I just ordered the one from the fasttech website, I hope the pins on the DB9 are the same on my CAN-USB adapter... If not I'll have to do some cut/paste...

 

[triakter]

Any updates on your experiments, ElectricLove? I just bought a 2.0 and wondered if you're going to have a high performance battery upgrade available soon

 

[ElectricLove]

The response I received from the TMC forum in general on the idea of developing this thing was very disruptive to the process (basically cut me off from discussing it with the forums), because of that steam was lost in the development of this battery pack. We are getting more "cores" in though, which we want to use for furthering development of a Roadster-HP battery pack...

It is tough to develop this stuff without the community support due to this portion of the company (EV) being very small, its basically a one-man operation and I've been given limited budget (which means it gets used on more lucrative markets than Roadster), I really thrive on people like you (triakter and other positive members) being optimistic about figuring something new out!

 

[wiztecy]

ElectricLove, you had many optimistic supporters in the beginning. Even I supported you. But when I started seeing some things that were unprofessional in my taste, you lost my support as well as others. Its easy to gain trust, not so much gaining it back.

This is a very small and closely knit community and I enjoy that privilege. With that everyone looks out for everyone else, nobody want's to see their friend get burned nor get burned themselves.

 

[ElectricLove]

I understand wiztecy, unfortunately most (if not all) of the stuff that was unprofessional had "nothing" to do with me... I say "nothing" b/c I do get that I am related to the company by employment, for better or for worse...