Recent content by iisjsmith

The ESS is not a single large pack arranged in a 99S69P configuration. SRB posted this link (www.elecdesign.com/Articles/Index.cfm?AD=1&ArticleID=14108) on the Tesla Motors blog. It has all the specs, and I've been able to work out some numbers. Each cell is 3.6V and 2200mAh. The cells are...

We cleared this up on page 2. The ESS is not a single large "pack" with all the cells arranged in a 99S69P config. There aren't two different packs with two different discharge rates.

> Gearbox? There ain't any. I guess only posibility are some internal reduction gears, You are right, on their Q&A section the say "no gearbox". But aren't reduction gears used to decrease rotational speed for an increase in torque? They need to increase rotational speed by a factor of, at...

Oh, I am not insinuating that field weakening is responsible for the torque drop off on the Roadster once it hits 6000rpm. I know that is something you mentioned, but I'm not so sure. The reason I'm not so sure field weakening is responsible for the drop in torque is because once you exceed the...

> Toyota seems to have gotten around this on their AWD Highlander and Lexus Hybrid models that do not have any linkage between the front wheels and the rear wheels. We are talking more here about the link between the two rear wheels. Tesla has said that the reason they decided to use a single...

Well they must be doing something with a gearbox, because on the PML Flightlink website they list the HPD40 with a maximum speed of 2000rpm. http://www.pmlflightlink.com/motors/hipa_drive.html Otherwise that's a mighty nice motor. 750Nm 120kW and only 25kg.

> Why wouldn't dual inboard motors fit the legislation? Well it says in the first post that: the certification regulations are written assuming you have one motor and a drivetrain, so there are some certifications (such as the one for Anti-Lock Braking) you can't pass in a car with no...

I simply want to stand by my statement that you do not need to increase voltage when you are increasing the frequency. You can increase the frequency, thus increasing the speed at which the motor turns, without drawing additional energy from the energy source. When you do this you take a hit in...

I wonder what impact it would have made on their decision if they threw out the safety certification regulation issues. I know they have said time-and-time-again that in-hub motors reduced handling too much to be a viable option, but the idea of dual rear motors is interesting. I completely...

Oops, scratch most of those kW numbers. I forgot :-[ that the voltage does not stay at a constant 324V...the voltage is slowly scaled up to line voltage by the inverter as it slowly scales up the frequency. So the numbers for full power are correct, but I need to re-work the other numbers.

Here are some numbers I worked up, after figuring out the Roadster ESS specs: The ESS is 324V and 152Ah. To drain the ESS in one hour you discharge at a 1C rate, which is 152A. 152A * 324V = 49248W or 49.3kW or 66.1hp. So if we supply 49.3kW of power for one hour we will completely drain the...

To put real numbers on the C rate issue, use the numbers from the Roadster. The Roadster ESS has a capacity of 152Ah. It will provide 152A for one hour if you discharge it at a 1C rate. If you discharge the ESS twice as fast, in 30 minutes, you will discharge at 2C and it will provide 304A. You...

At 90grams the 26650VTs are also twice the weight of a standard 18650. The plan would be to use fewer of the 26650VTs in a future ESS, so that the weight wouldn't change. But I don't think you could get the same performance out of only ~3400 26650VTs. The thing that really got me interested...

Okay, I found out all the info we need. SRB posted this link (www.elecdesign.com/Articles/Index.cfm?AD=1&ArticleID=14108) on the Tesla Motors blog. It has all the specs, and I've been able to work out some numbers. Each cell is 3.6V and 2200mAh. The cells are arranged into sheets, with each...

From Battery University.com (very nice site) at http://www.batteryuniversity.com/partone-16.htm: What is C-rate? The charge and discharge current of a battery is measured in C-rate. Most portable batteries are rated at 1C. This means that a 1000mAh battery would provide 1000mA for one hour if...