What kind of performance would the Tesla have

[lutach]

Originally Posted by Lauri

lutach, check the energy density for the Panasonic cells Tesla is using and about which you posted the spec-sheet pdf. They are 202Wh/kg - which is VERY GOOD, if the specs can be trusted!

For comparison on my 1/8 buggy I'm using 5Ah 4S softcase LiPos (35C and 40C) which weigh around 530g which makes only 140Wh/kg. Sure those can give out A LOT power but when speaking about Tesla you are speaking about a regular car, not a racer or a dragster. So my 1/8 buggy battery pack is +45% lighter than the Panasonic cells. If I would not be racing 10-minute heats but 60 or 120-minute heats I'd be running those Panasonic cells just like Tesla :)

If I would be building an electric car (just give me the money ;) I'd also be getting the batteries which have the best energy density and can provide enough power/curren.

You've all talked about heavy batteries and then you want those heavy batteries just for the fact that they'd be able to deliver more power. Obviously the lighter cells can provide _enough_ power while being 45% lighter for an example.

If you run 10-minute then you need avarege of 6C current from the batteries (60min/10min=6). If you'd like to drive around 3 hours with your electric 1/1 car then you'd only need 60min/180min=0.3C batteries. With a fullsize car you are not going to accelerate and brake every 3 seconds like you are doing with small scale RC-cars. You maybe accelerate for 4 seconds to reach 100kmh and then drive until next red light.

In real life you only need 0.3C capable batteries that can provide the maximum power for 5 or 10 seconds. What's the time it takes for Tesla to reach its maximum speed? It won't be more than 10 sec I'm guessing.

For passanger car I'd like to have a battery, that:
- has good lifetime and many lifecycles
- can give out enough power to accelerate the car up to 100kmh in decent time ie 5s for sports car, 10s for regular car
- has best available energy density so you don't have to accelarate and brake the extra mass all the time
- has ok cold performance.Won't like to spend too much power to keep the battery very warm.

Energy cell will always have a higher energy density, but when you add a load higher then the cells are capable of handling, the voltage drop is way higher which will make the energy density a lot different. The cells I can get offers the absolute best energy density and all I would need is a pack that weighs only 250lbs. to give the same performance as the 1000lbs. Tesla pack. The Panasonic cell is not safe as it can't vent when things go wrong. It wasn't meant for cold weather. Life cycle doesn't come close to the military spec cells they could've gotten.

Energy cell is good to offer something that doesn't consume a lot of power a longer lasting charge, but when that cell is used in a power application, things can get a little on the dangerous side.