Refreshed 90kwh packs are actually 100kwh [Speculation]

[R.S]

I am on your camp, we don't need larger batteries which weigh more and take longer to charge, what we need is quicker charging and increase drive efficiency. If they can increase drive efficiency 10% thats the same as if the battery were a 100kwh

Increasing drive efficiency is hard, especially by 10%. The added costs might even surpass the cost of 10kWh added battery. But again faster charging could also be a part of the solution. The faster you can charge the battery the more you can recuperate. 10% seem a little much just with that, but it might help a bit. Riverspeed, although being a Hydrogen car, has a very clever super capacitor solution. The car is very small, but they can recuperate with 50kW. A Model S can only take a bit more than 60, as far as I know, although being much heavier.

Not that I think Tesla needs supercaps, but if the battery is able to take more energy, you loose less through breaking.

 

[wdolson]

I am on your camp, we don't need larger batteries which weigh more and take longer to charge, what we need is quicker charging and increase drive efficiency. If they can increase drive efficiency 10% thats the same as if the battery were a 100kwh

There is very little that can be done to increase efficiency, EVs are already around 3X more efficient than ICE and between 75% and 90% of the energy in the battery is turning the wheels. As you get going faster, the efficiency drops, but most of that is due to aerodynamic drag. There are a few things that can be done for efficiency, the new slipstream wheels are a bit better than the old standard wheels. Early on the Model S had an aero wheel option which had a flat disk instead of spokes and that did reduce drag by measurable levels. When the laws change that require rear view mirrors, the mirrors could be replaced with cameras, but that is a legislative issue that's going to take a while to happen. Tesla could introduce aero rear wheel covers, but there would be a lot of criticisms that they are ugly.

If you want an attractive car, there isn't much more than can be done to improve efficiency as aerodynamic efficiency is the only thing left to improve.

The speed of charge is very dependent on the battery chemistry and Tesla pushes the chemistry we have now as far as it can be pushed without damaging the batteries.

 

[wdolson]

Increasing drive efficiency is hard, especially by 10%. The added costs might even surpass the cost of 10kWh added battery. But again faster charging could also be a part of the solution. The faster you can charge the battery the more you can recuperate. 10% seem a little much just with that, but it might help a bit. Riverspeed, although being a Hydrogen car, has a very clever super capacitor solution. The car is very small, but they can recuperate with 50kW. A Model S can only take a bit more than 60, as far as I know, although being much heavier.

Not that I think Tesla needs supercaps, but if the battery is able to take more energy, you loose less through breaking.

Supercapacitors today have much lower charge density than good quality Li-ion batteries. That's the primary technical challenge with them.

 

[brianman]

As you get going faster, the efficiency drops, but most of that is due to aerodynamic drag. There are a few things that can be done for efficiency...

Change the shape of the vehicle from the perspective of wind? Magic, magnets, lasers, force-fields. Maybe some unicorn dandruff.

 

[badbot]

Why would Tesla software limit the battery pack?

Tesla limits all battery packs to safe levels of discharge. the inverter has sensors for current draw and the computer adjusts output. if the current exceeds safe levels the fuse blows.
When you go to Insane or Ludacris the computer changes the allowed draw.

 

[wdolson]

Change the shape of the vehicle from the perspective of wind? Magic, magnets, lasers, force-fields. Maybe some unicorn dandruff.

You can make a car like this:
http://phys.org/news/2013-06-supermileage-vehicle-mpg-mph.html

but it isn't going to be street legal and has quite a few drawbacks for everyday use. This particular example is only capable of 15 mph which is a little shy of the capabilities of a daily driver.

 

[brianman]

You can make a car like this:
http://phys.org/news/2013-06-supermileage-vehicle-mpg-mph.html

but it isn't going to be street legal and has quite a few drawbacks for everyday use. This particular example is only capable of 15 mph which is a little shy of the capabilities of a daily driver.

Nah, the idea was to have the "natural physical shape" / "resting shape" be akin to the Model S to which we're accustomed, but have the "in-motion" aerodynamic profile be "actively" modified to be better than that.