higher capacity ESS for Roadster

higher capacity ESS for Roadster

Hello Roadster owners,

who would like to try out a prototype battery pack constructed with the new Panasonic 3.1Ah 18650 cell? I guestimate that current ESS uses 2.2Ah cells, so this should increase range from 245 miles to 345 miles at the same weight.

If yes, would you to back to TESLA and ask for such a pack to be made available to you? Maybe in a "friendly user" field test program? This surely would help collecting real world data with the new Panasonic cell. By the time Model S hits the road, some super high capacity / super light weight battery pack would be available.

VolkerP | 13 May 2011

oops that would be Ah not mAh. Sorry.

Sparrow | 14 May 2011

Depending on cost, I would consider it.

JackB | 16 May 2011

I'm guessing that Tesla has its hands full with the model S development right now, but a pack like this is a natural progression at some point. As a range junkie that likes to test the limits of long-distance travel, I would definitely purchase a pack like this once it becomes available.

jewelbox | 18 May 2011

I think so would most roadster owner. At least EU based ones since the speed limits are higher and the normal car usage in EU seems to be of a somewhat longer average distance per day than in the US. I for one would sign up in an instance!!

Timo | 18 May 2011

Um, did you get US and EU reversed? US is wide country much less densely populated than most of the continental Europe. Also what I have read many US motorways have higher speed limits than most of the Europe has, or at least those sections of the roads are much longer than common EU motorways.

DHrivnak | 20 May 2011

Realistically, I have found I can work well with the 230 mile range, especially now that I have a J1772 adapter. But when the pack begins to fall off I sure hope Tesla or a good third party will sell a longer range pack. It appears that one of the best ways to protect the battery is not take it to the limit.

andy | 16 June 2011

If it were available I'd buy one now.

jmollenkopf | 16 June 2011

What would be really cool is if they would offer me one with my new car due for shipment in August. I would most probably pay the "incremental cost" for the extra range.

Is the issue the 4c rating as to why these cells may not be available today?

VolkerP | 17 June 2011


Tesla states that they sell the-generation-before cells in production cars. Only cells of proven reliability and durability. To me this appears to be a "better safe than sorry" approach. But we know that there are quite a few people out there that would make a big fuss from a Tesla car with failing battery cells.

The suggested "extra capacity pack" would not be a standard or even an option. Go and ask for it and sign some NDA papers that you won't call the press (especially BBC) if your ESS fails.

rsdio | 19 June 2011

Uh, these aren't simply D-cell batteries that you buy in the grocery store and plug into your boom box. A significant amount of engineering goes into designing a battery pack around a very specific cell type, and so many details hinge on the cell type. Tesla cannot simply just toss this new Panasonic super cell into a Roadster battery pack and then let owners drive off with them. There would be several man-months of development time just to get validation prototypes working. Then you have all of the automotive safety standards to comply with before anyone outside the test staff would get their hands on this.

Hey, if you think it's so easy that all Tesla needs are volunteers, then just start your own EV battery company and engineer your own pack based on the new Panasonic cells. Tesla Roadster owners would certainly be happy to have a third-party option in the future when the original packs wear out, and the competition would certainly keep the price as low as possible.

I'm not trying to pick on anyone, but it sometimes seems like blogs and forums overlook the significant amount of design work that goes into state-of-the-art technology like the Tesla Roadster. There are a lot of steps between reading a Press Release about a new OEM product and seeing that product incorporated as an upgrade for an existing design - at least not unless there are standards that make it possible to mix and match.

jmollenkopf | 20 June 2011


I think you are right about the certification for safety..surely some red tape to cut through, but the batteries are the same physical size (i.e. 18 mm X 65 mm) and voltage. The only difference being the capacity. If they have the same or better discharge amp rating ("C" rating) then a little firmware upgrade to calibrate the miles to empty should suffice. My experieince is with model airplanes with LiPo batteries. Buy a higher mah rating and plug and play works fine. They just fly longer. Careful when you crash though, they do catch on fire every now and then when damaged. I would think Panasonic would have to do significant testing before the batteries are for sale to certify ratings long before Tesla would get them.