A bigger motor

Takumi · 03-24-2007, 04:42 AM

I'm surprised nobody has put this up. They've already stated that a bigger, stronger motor is more efficient...you get more bang and I believe this is cheaper than replacing the entire battery array.

But someone posted on one of the blogs that their engine might be what we're looking for. Instead of going bigger, you can go smaller.
Go to the FAQ at the bottom left:
http://power.friesen-research.com/

Tesla2Go · 03-24-2007, 06:41 AM

Would the top RPM matter? On their page I see the 200 HP motor is rated at 1795 rpm, isn't that too low?

Sk8orDie · 03-24-2007, 07:27 PM

No the RPM doesn't matter. With gears you can find the proper ratio for driving fast enough.

The bigger Problem is the weight of the motor. something over 600 pounds seems to heavy to .

An average AC_Motor has an effency over 90%, so if you get 99%, it's only an 10% improvement.

The Motor in the Tesla works fine, though some people think taht AC-Motos are not the best solution for cars, but that's like a religious war. ;-)

To say it clearly: The Battery is the problem/solution. If Altair Nano or EEstor manage it to bring their predictions to realworld market, they will be the big winners. Today you'll have to pay about 1000$ / kWh batterystorage. If the Price will hit 200$ or better 100 $ than the mobile revolution will beginn. You'll have to get the costs down. It's the same reason why we don't drive FCEV or H²-ICEs, they are simply too expensive.

Hopefully the battery guys will do good job, so we can smash our Gasguzzlers.

Best regards from Germany

Takumi · 03-26-2007, 02:13 AM

Ah, you guys are missing the point. This is a modifications thread. All modders/tuners strive to achieve maximum efficiency. A little here and a little there can add up.

Tesla's technical specifications page doesn't say who they sourced the motor from, but if I remember correctly - AC Propulsion.

http://www.teslamotors.com/engineering/tech_specs.php

...and how heavy is that motor?

Is the motor that Tesla is using the most efficient or just the most cost effective? Who out there makes the best motors? I'm sure this technology is not that young. Does Siemens make motors? Solectria? Advanced DC Motors?

tonybelding · 03-26-2007, 05:05 AM

Quote:

Originally Posted by Takumi

Tesla's technical specifications page doesn't say who they sourced the motor from, but if I remember correctly - AC Propulsion.

Nope. . . Tesla produce their own designed motors in their own factory. They consider it part of the "secret sauce" that makes their car special, along with the design of the ESS. They did license some motor technology from AC Propulsion, that's all.

Quote:

...and how heavy is that motor?

About 70 pounds. They also claim it's about 85-95% efficient, so I'm guessing there's not a lot to be gained from tinkering with it or replacing it.

I'm not optimistic about hot-rodding the Roadster and getting big increases in power or performance. It could be possible to tweak certain things. . . Somebody might "chip" the motor controller to change some of its characteristics. It's always possible to strip weight off the car. The gear ratios would be a natural target for tinkering with. And eventually there will be upgraded batteries, though I'm sure longer range will be more the goal than speed performance. But the motor? Hmm, I just don't see much potential there. It's not like a gasoline engine, you can't bolt on a supercharger or a nitrous kit!

WarpedOne · 03-26-2007, 12:40 PM

I still think removing some portion of battery pack would improve the performace numbers. I find it hard to believe all those batteries are there just to provide minimal required power density. Remove half of the pack and you gain cca 220kg, which roughly translates into 10% better acceleration and deceleration, better handling etc.

Of course, range is at least halved, batteries age a lot faster etc.

W8MM · 03-26-2007, 01:45 PM

Quote:

Originally Posted by WarpedOne

I still think removing some portion of battery pack would improve the performance numbers. I find it hard to believe all those batteries are there just to provide minimal required power density. Remove half of the pack and you gain cca 220kg, which roughly translates into 10% better acceleration and deceleration, better handling etc.

Of course, range is at least halved, batteries age a lot faster etc.

Be careful.

Removing any of the battery capacity also has the effect of reducing the peak current capacity available from the total pack.*

In electric cars, current = torque.

WarpedOne · 03-26-2007, 04:22 PM

I know, that is why I said: "I find it hard to believe all those batteries are there just to provide minimal required power density".

I doubt the ESS and PEM are designed to draw maximum available (and allowed by Li-Ion chemistry) current at any time. I'd guess they are designed with reasonable safety margins to allow for the batterries to last longer by not taxing them to the max. If someone is willing to sacrifice their lifetime, he could probably eak out some "advanced" performance:)

W8MM · 03-27-2007, 07:12 PM

Quote:

Originally Posted by WarpedOne

I know, that is why I said: "I find it hard to believe all those batteries are there just to provide minimal required power density".

I doubt the ESS and PEM are designed to draw maximum available (and allowed by Li-Ion chemistry) current at any time. I'd guess they are designed with reasonable safety margins to allow for the batteries to last longer by not taxing them to the max. If someone is willing to sacrifice their lifetime, he could probably eak out some "advanced" performance:)

As I understood the explanation during my San Carlos tour, improvement in the effective series resistance of the battery pack is the key to better performance.

When the back EMF of the motor rises with increasing motor RPM, the battery pack terminal voltage (cell voltage minus IR drop) determines the maximum RPM at which full current is still available.* If the battery pack terminal voltage sags with current demand, the maximum RPM for full torque sags as well.* Lower internal battery pack resistance (cell construction) will reduce terminal voltage sag and increase the motor RPM at which full torque is available.*

Further progress in low internal resistance battery cells is the key to "hot-rodding" the Tesla Roadster.

WarpedOne · 03-28-2007, 01:56 AM

Hmmm, sounds logical. I therefore back away from my previous suggestion of halving the battery-pack.

But I still have one more idea: different gear ratios* :D

Roadster reaches 130mph at its redline at 13000rpm in second gear. At this rpm there is only about 105kW of power awailable. With a longer third gear it could reach at least 170mph.

Edit: typoos