News coming from Engadget... Panasonic's 3.1Ah batteries to be used in the Tesla Model S, have highest energy density yet -- Engadget

Read that this morning too. Hey, at least it's better news than a new roadster color-matched to Kodak's logo

News about Model S The news about the high density Panasonic battery is appreciated. We'll take all the news we can get! I liked the CNN bit that was posted on Facebook, too, about the government loan being earmarked only for the Model S. It was encouraging.

Yes. Looking at the battery specs, it is a 3.6V, 3.1Ah, 45.5g cell. Cylindrical type | Lithium Ion Batteries | Batteries, Power supplies | Panasonic Industrial Solutions Global Given the rumored ~8000 cells for the 300 mile Model S, this works out to 89kWh. The Roadster gets 236 miles EPA combined on 53kWh and would be rated at 396 miles on 89kWh. So on the Model S, it should be reasonable to expect to top 300 miles on this kind of pack. As for weight, it works out to 364kg/802.5lb for the cells. The Roadster cells (6831 of them) seem to be 3.6V, 2.15Ah, 44g cells, working out to 300.5kg/662.3lb. The cell weight increase would be 63.5kg/140.2lb, which isn't too bad for so much more capacity. Everything seems lined up for them to hit their 300 mile target.

I thought the weight of the Roadster's battery pack was said to be around 900 lbs, maybe close to 1000 lbs? I realize you are going off the specs of the battery, but that seems like a fairly big discrepancy. Can someone set me straight? -Shark2k

That's great news then. I wonder what they'll do with the Roadster then? I imagine they wouldn't want to change the weight distribution at this point but they could extend the range I guess.

I'm relatively not familiar with the charging of this huge kind of battery pack... I'm just curious if for example a 53kwh tesla roadster, how long will it charge assuming a 240v 30 amp setup? Starting let's say a 10% charge left... 89 kwh will take more hours I think...

That's part of the reason why I highlighted the weight increase on a cell level rather than trying to guess a total pack weight, since so far we don't really know how much extra weight all the other stuff adds. The ~240-340lb discrepancy for the Roadster pack is fairly big, but considering the aluminum shell, plumbing for the coolant that has to run to each cell, wiring, computers, sensors, then it becomes a bit less unreasonable. Of course, both the cell and pack weight are estimates and we don't know if Tesla bought Panasonic cells (or those specific 44g cells I found on Panasonic's site) for the Roadster, so those can play a part too. A rough estimate can be easily done in these cases. 240v * 30 amp = 7200 watt = 7.2 kW (using voltage * current = power, in terms of units: volt * amp = watt) kWh (kW*h) is just the product of kilowatt (kW) and hour (h). 53kWh / 7.2kW = 7.57 hours (notice the kW cancels out). 89kWh / 7.2kW = 12.36 hours

Note, we tend to do the math assuming 100% charging efficiency which isn't right. It would actually take a bit longer to charge from full to empty than the 'simple' numbers suggest. On the other hand, people rarely recharge from fully empty so in practice, most "real-world" recharge times are usually far less.

FYI it was posted here earlier in the day. Please check obvious other threads, rather than starting another one. The speculation that this is the Model S 300 mile cell has also been a regular feature, here for one.