Bad Karma - it left me stranded!

33530 Views 111 Replies 26 Participants Last post by kabalah70, Feb 16, 2012

ffcars

Discussion Starter · Feb 3, 2012

My car has about 160 miles on it with 6.14 loaded. On Monday it would not go into D or R. I did several hard reboots and it didn't fix it. The Altanta Fisker tech came over to my house and did another hard reboot and it worked.

So this morning I go to take the kids to school and it wouldn't go into D or R. I did a hard reboot and it worked.

Dropped off one of the kids at pre-school and when I came outside, the car wouldn't go into D or R. I tried several hard reboots and it didn't work. So there I sat in a parking lot with my hood open for 30 minutes wondering what would have happened if my wife were driving with our two small kids. This is not acceptable.

A car made in 2011 or 2012 should never leave a person stranded. Software bugs I can handle, but this is not going to be a car I can depend on until they work out this bug.

After 30 minutes I did another hard reboot and it worked. Took the car home and parked it. I'm be driving the Ford today.

21 - 40 of 112 Posts

Sigurd

· #21 · Feb 4, 2012

I'm not blaming the guy for his car having problems. I am only pointing out learning points that we can all benefit from. I'm sure that if ffcars knew what he knows now, then he would have had his car flat bedded to the dealership as soon as he couldn't engage D or R the first time. He went through a "worst case scenario" that we can now learn from and prevent.
If I were to blame anybody, it would be the Fisker service tech that came to his house and did a hard reboot without investigating further.
Cheers,

ffcars

Discussion Starter · #22 · Feb 4, 2012

Karma31 said:
I feel your pain, brother. Simply amazing how rock solid the Ford GT has been despite incredibly short gestation period. I hope Fisker doesn't take as long as Gates did to get a stable Windows platform lol

I bought the FGT new in July 2006. It now has 22,000 miles on it, several track days and even driven it in snow. It's never left me stranded and has always started. I have bought two rear tires, 4 oil changes and that's it!!! It's never been to the dealer for a warranty repair.

And I believe the FGT was developed in 4 years or something crazy.[hr]

Sigurd said:
I think the moral of this debacle is: If your car will not go into gear, have the dealership pick it up so you won't get stranded. If you do a hard reboot and it all of a sudden works, be ready for the initial problem to resurface and leave you stranded.
I think that all check engine lights and other warnings need to be checked out by a Fisker dealership and not just ignored and the "reset" by doing a "hard reboot". I think the "hard reboot" option should only be used in an emergency when you need to try something because your wife is stuck on the road, not at home in your garage so you can go drive to tempt fate.
How many times were ffcars Karma "hard rebooted" before his wife was stranded? It obviously had an unresolved issue. If the car had a problem that convinced him it was not smart to drive and he decided to take the Ford that day, why did his wife take the problem car?

The dealer is the one who told us to do hard reboots. Even the dealer tech who came to my house didn't bother hooking up the OBDII to his computer to read the codes. He did the hard reboot without checking anything else.

I'm not sure why my wife took the car. And I'm sure as heck not going to ask. But I think she wanted to drive it and see if it does it again so she could tell the dealer to come get it. When it strander her the dealer never called her back to come get the car.

[hr]
By the way, the service tech who came to the house knows the person who helped develop the software. The car's 0-60 times are limited by the software. He said the car can do 0-60 in about 3.5 seconds, but the batteries would be toast pretty quickly and tires wouldn't last very long. And since they are offering a 5 year warranty on the batteries, they decided to limit the performance.

The computer code is read through the OBD-II port. There are 16 pins on the OBD-II connector. Most cars use 5 or 6 pins at the most. The Fisker Karma uses 14 pins! The system is more complicated than any other production car in history. That scares the crap out of me. Why? Because if you are going to launch the most complicated, some might say advanced, car in the world, you better have the best programmers and road testers to make sure that 100% of the systems work and they work for 100,000 miles on at least 3 production models.

I was hoping someone would be able to tap into the code at some point to allow us to all to select options like performance, dash colors, fonts, button colors, etc. But I doubt anyone will be able to crack this without insider knowledge.

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siliconkiwi

· #23 · Feb 4, 2012

I also experienced the no-DNR issue once, fortunately it was when I was trying to restart the car after noticing that I did a crappy parking job, and wanted to straighten it up. I just left it there, came back 4 hours later and it was fine (no hard reboot). I'm on 6.13.

Karma 2012

· #24 · Feb 4, 2012

To me, this is just not acceptable for any new car. I can fully emphasize with your wife. I would not be happy in her situation also.

my car is at Atlanta Fisker right now being upgraded from 6.10, 6.11, 6.12, 6.13, then 6.13.5 according to them. We will see what happens when I pick it up later today. I am mentally prepared now.

In the medical field:

DNR= do not resuscitate

lol...

Sigurd

· #25 · Feb 4, 2012

The greatest statement all morning:

ffcars said:
I'm not sure why my wife took the car. And I'm sure as heck not going to ask.

I just blew coffee all over my laptop.
Cheers,

[hr]
Again, I think ffcars and his wife has every right to be livid with the Fisker mechanic that did not do any repairs to the car when he came out. A "hard reboot" does not fix any problems. It doesn't fix hardware or software issues. It only erases the memory of them so they can re-appear at a worse time.
When my Mercedes needed new fuel sending units and after they installed them, my wife ran out of gas because the gas gauge didn't give her low gas warning, she was pissed. When they replaced the units again and I ran out of gas on a busy highway with what appeared to be a quarter of a tank of gas on the gauge, I was beyond irritated.
I don't think anybody on this forum thinks it is acceptable for any new car to leave you stranded.
Cheers,

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Sparky168

· #26 · Feb 4, 2012

siliconkiwi said:
I also experienced the no-DNR issue once, fortunately it was when I was trying to restart the car after noticing that I did a crappy parking job, and wanted to straighten it up. I just left it there, came back 4 hours later and it was fine (no hard reboot). I'm on 6.13.

This sounds to me there is a floating ground problem. Over time the charge dissipate and the ground potential restores back down to normal.

The new ground strap seems to have solved a lot of erratic electronic problems before.

Is there more ground strap required still at other location of the car?

Nimisys

· #27 · Feb 4, 2012

I have witnessed this on cars, with 613.5 and the ground re-work. It's been an errant software bug from as far back as 607. You will see a flashing green READY light, but no other fault indications. I have found it happens most often if you try to engage D or R before the instrument panel finishes its WOW animations while also unlocking the CIU. So far the only solution i have found is to turn the car off, wait the two minutes for it to go to sleep (all the lights off on the drive selector unit) and then restart, allowing time for the car to fully wakeup before selecting D or R.

Sparky168

· #28 · Feb 4, 2012

Nimisys said:
I have witnessed this on cars, with 613.5 and the ground re-work. It's been an errant software bug from as far back as 607. You will see a flashing green READY light, but no other fault indications. I have found it happens most often if you try to engage D or R before the instrument panel finishes its WOW animations while also unlocking the CIU. So far the only solution i have found is to turn the car off, wait the two minutes for it to go to sleep (all the lights off on the drive selector unit) and then restart, allowing time for the car to fully wakeup before selecting D or R.

A race condition. Must be able to put Karma to sleep, not shut-down when turning off the car, so a faster wake-up time next time, instead of a full reboot from scratch everytime.

Something like the options on Windows Vista to select sleep or shut-down. Otherwise, Karma wouldn't make a good get-away car after your visit to a bank

.

magnus

· #29 · Feb 4, 2012

ffcars said:
By the way, the service tech who came to the house knows the person who helped develop the software. The car's 0-60 times are limited by the software. He said the car can do 0-60 in about 3.5 seconds, but the batteries would be toast pretty quickly and tires wouldn't last very long. And since they are offering a 5 year warranty on the batteries, they decided to limit the performance.

Errr... I find this pretty hard to believe.

AnOutsider

· #30 · Feb 4, 2012

ffcars said:
He said the car can do 0-60 in about 3.5 seconds,

I have no doubt they artificially limited things (especially for emissions), but with the weight of the Karma I find this really hard to believe.

Sparky168

· #31 · Feb 4, 2012

magnus said:
ffcars said:

By the way, the service tech who came to the house knows the person who helped develop the software. The car's 0-60 times are limited by the software. He said the car can do 0-60 in about 3.5 seconds, but the batteries would be toast pretty quickly and tires wouldn't last very long. And since they are offering a 5 year warranty on the batteries, they decided to limit the performance.

Click to expand...

Errr... I find this pretty hard to believe.

I want to calculate if it is possible to get 0-60 mph in 3.5 sec with a 5,000 lb Karma.
What is the horse power required to go 0 - 60 mph in 3.5 sec for a 5,000 lb car, assuming constant acceleration and 100% efficiency.
To work with metric, converts 60 mph to 26.82 m/s.
Acceleration = delta V/delta t = 26.82 m/s / 3.5 s = 7.6628 m/s^2
Force = mass x acceleration = 2,272 kg x 7.6628 m/s^2 = 17.4 KN
What is the distance travelled in 3.5 s?
delta d = a x (delta t)^2 / 2 = 7.6628 m/s^2 x (3.5 s)^2 / 2 = 46.935 m
Power = Force x distance / time = 17.4 KN x 46.935 m /3.5 s = 234 KW
What is the available power from the electric motor and from the battery.
From the electric motor, we know it has 400 hp which is 298 KW. This is 27% greater than the 234 KW, so the motor is capable.
What about the battery?
For 20.1 KWh energy storage on a Karma, there are 310 cells, each stores 65 Wh. Each cell is 496 g. 310 cells is 153.76 Kg. The specification says 2,400 W/kg.
Therefore total KW = 153.76 kg x 2,400 W/kg = 369 KW.
http://info.a123systems.com/data-sheet-20ah-prismatic-pouch-cell/
The battery is oversized to the motor by 23%. So the battery is quite capable to drive the motor to its full capacity of 298 KW. And the motor has 27% more power to drive the Karma to accelerate from 0 - 60 mph in 3.5 s. The battery would have been working in 63% of its output capability.
Doing similar calculation for 0 - 60 mph in 6.1 s. The battery is working at 36.3% of its output capability.
So for you speed demon out there, you know your Karma has more stuff inside, just not showing it

Also the Buckeye Bullet 2.5 using the A123 battery has broken the 300 mph land speed record. The Buckeye Bullet 3 will try to break 400 mph this year! You definitely have a fast car inside

http://evworld.com/news.cfm?newsid=26270

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ct-fiskerbuzz

· #32 · Feb 4, 2012

Sparky168 said:
I want to calculate if it is possible to get 0-60 mph in 3.5 sec with a 5,000 lb Karma.
What is the horse power required to go 0 - 60 mph in 3.5 sec for a 5,000 lb car, assuming constant acceleration and 100% efficiency.
To work with metric, converts 60 mph to 26.82 m/s.
Acceleration = delta V/delta t = 26.82 m/s / 3.5 s = 7.6628 m/s^2
Force = mass x acceleration = 2,272 kg x 7.6628 m/s^2 = 17.4 KN
What is the distance travelled in 3.5 s?
delta d = a x (delta t)^2 / 2 = 7.6628 m/s^2 x (3.5 s)^2 / 2 = 46.935 m
Power = Force x distance / time = 17.4 KN x 46.935 m /3.5 s = 234 KW
What is the available power from the electric motor and from the battery.
From the electric motor, we know it has 400 hp which is 298 KW. This is 27% greater than the 234 KW, so the motor is capable.
What about the battery?
For 20.1 KWh energy storage on a Karma, there are 310 cells, each stores 65 Wh. Each cell is 496 g. 310 cells is 153.76 Kg. The specification says 2,400 W/kg.
Therefore total KW = 153.76 kg x 2,400 W/kg = 369 KW.
http://info.a123systems.com/data-sheet-20ah-prismatic-pouch-cell/
The battery is oversized to the motor by 23%. So the battery is quite capable to drive the motor to its full capacity of 298 KW. And the motor has 27% more power to drive the Karma to accelerate from 0 - 60 mph in 3.5 s. The battery would have been working in 63% of its output capability.
Doing similar calculation for 0 - 60 mph in 6.1 s. The battery is working at 36.3% of its output capability.
So for you speed demon out there, you know your Karma has more stuff inside, just not showing it
Also the Buckeye Bullet 2.5 using the A123 battery has broken the 300 mph land speed record. The Buckeye Bullet 3 will try to break 400 mph this year! You definitely have a fast car inside
http://evworld.com/news.cfm?newsid=26270

Your numbers appear to work pretty well, although 2500 kg is closer: the curb weight is 5300 lbs = 2405 kg; then add 95 kg for driver. (I did not check all of them but those I did were spot on.) So using 2500 kg we get more like 19 kN, which requires ~255 kW (just over 340 hp) to get 0-60 in 3.5 sec.

That's at 100% efficiency though. The motors lose efficiency at near-zero RPM. Real world conditions suggest adding at least a second or two to that. Still, 0-60 in 5 seconds is a lot faster than 0-60 in 6.1 seconds....

SoCalGuy

· #33 · Feb 5, 2012

ct-fiskerbuzz said:
Sparky168 said:

I want to calculate if it is possible to get 0-60 mph in 3.5 sec with a 5,000 lb Karma.
What is the horse power required to go 0 - 60 mph in 3.5 sec for a 5,000 lb car, assuming constant acceleration and 100% efficiency.
To work with metric, converts 60 mph to 26.82 m/s.
Acceleration = delta V/delta t = 26.82 m/s / 3.5 s = 7.6628 m/s^2
Force = mass x acceleration = 2,272 kg x 7.6628 m/s^2 = 17.4 KN
What is the distance travelled in 3.5 s?
delta d = a x (delta t)^2 / 2 = 7.6628 m/s^2 x (3.5 s)^2 / 2 = 46.935 m
Power = Force x distance / time = 17.4 KN x 46.935 m /3.5 s = 234 KW
What is the available power from the electric motor and from the battery.
From the electric motor, we know it has 400 hp which is 298 KW. This is 27% greater than the 234 KW, so the motor is capable.
What about the battery?
For 20.1 KWh energy storage on a Karma, there are 310 cells, each stores 65 Wh. Each cell is 496 g. 310 cells is 153.76 Kg. The specification says 2,400 W/kg.
Therefore total KW = 153.76 kg x 2,400 W/kg = 369 KW.
http://info.a123systems.com/data-sheet-20ah-prismatic-pouch-cell/
The battery is oversized to the motor by 23%. So the battery is quite capable to drive the motor to its full capacity of 298 KW. And the motor has 27% more power to drive the Karma to accelerate from 0 - 60 mph in 3.5 s. The battery would have been working in 63% of its output capability.
Doing similar calculation for 0 - 60 mph in 6.1 s. The battery is working at 36.3% of its output capability.
So for you speed demon out there, you know your Karma has more stuff inside, just not showing it
Also the Buckeye Bullet 2.5 using the A123 battery has broken the 300 mph land speed record. The Buckeye Bullet 3 will try to break 400 mph this year! You definitely have a fast car inside
http://evworld.com/news.cfm?newsid=26270

Click to expand...

Your numbers appear to work pretty well, although 2500 kg is closer: the curb weight is 5300 lbs = 2405 kg; then add 95 kg for driver. (I did not check all of them but those I did were spot on.) So using 2500 kg we get more like 19 kN, which requires ~255 kW (just over 340 hp) to get 0-60 in 3.5 sec.

That's at 100% efficiency though. The motors lose efficiency at near-zero RPM. Real world conditions suggest adding at least a second or two to that. Still, 0-60 in 5 seconds is a lot faster than 0-60 in 6.1 seconds....

I highly doubt this for more commercial reasons. Firstly, Fisker first advertised that the car could go from 0-60mph in "5.8 seconds"... then it became "5.9 seconds" ... then "6.1 seconds" and now officially its "6.3 seconds." Fisker himself said the car could go 0-60 in "under six seconds"... now he says "about 6 seconds." If it was simply a software tweak, Fisker would have had some "burst mode" or "nitro mode" option on the Fisker controls to go 0-60 in 5 seconds or 4 seconds or whatever... so they could market the car as being able to go 0-60mph in "under 5 seconds" or "4.5 seconds" or whatever. You doubt that? Recall how many times Fisker kept saying "100mpg" in their adverts, interviews, etc... which became "67 mpg".... and now its "52mpg." It can't just be a software thing - its gotta be related to the unanticipated weight of the car and other mechanical/electrical issues (recall the car was initially expected to weigh around 4,500lbs).

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Sparky168

· #34 · Feb 5, 2012

SoCalGuy said:
I highly doubt this for more commercial reasons. Firstly, Fisker first advertised that the car could go from 0-60mph in "5.8 seconds"... then it became "5.9 seconds" ... then "6.1 seconds" and now officially its "6.3 seconds." Fisker himself said the car could go 0-60 in "under six seconds"... now he says "about 6 seconds." If it was simply a software tweak, Fisker would have had some "burst mode" or "nitro mode" option on the Fisker controls to go 0-60 in 5 seconds or 4 seconds or whatever... so they could market the car as being able to go 0-60mph in "under 5 seconds" or "4.5 seconds" or whatever. You doubt that? Recall how many times Fisker kept saying "100mpg" in their adverts, interviews, etc... which became "67 mpg".... and now its "52mpg." It can't just be a software thing - its gotta be related to the unanticipated weight of the car and other mechanical/electrical issues (recall the car was initially expected to weigh around 4,500lbs).

I suspect it is a trade off between the 0-60 time and battery life.How long is the battery warranty? So it could be at first, the paper calculation said it is doable under 6 sec. Then the A123 engineer did a battery life calculation and said cannot do. Back and forth and finalize at a safe number of 6.3 sec. Then software programs in the limit. Someone needs to ask Fisker to confirm.

I was merely checking to see if that Fisker mechanic or engineer(?) is in the ball park with his 3.5 s claim. With ideal 100% efficiency and no wind or wind at the back

, it seems possible.

SoCalGuy

· #35 · Feb 5, 2012

Sparky168 said:
SoCalGuy said:

I highly doubt this for more commercial reasons. Firstly, Fisker first advertised that the car could go from 0-60mph in "5.8 seconds"... then it became "5.9 seconds" ... then "6.1 seconds" and now officially its "6.3 seconds." Fisker himself said the car could go 0-60 in "under six seconds"... now he says "about 6 seconds." If it was simply a software tweak, Fisker would have had some "burst mode" or "nitro mode" option on the Fisker controls to go 0-60 in 5 seconds or 4 seconds or whatever... so they could market the car as being able to go 0-60mph in "under 5 seconds" or "4.5 seconds" or whatever. You doubt that? Recall how many times Fisker kept saying "100mpg" in their adverts, interviews, etc... which became "67 mpg".... and now its "52mpg." It can't just be a software thing - its gotta be related to the unanticipated weight of the car and other mechanical/electrical issues (recall the car was initially expected to weigh around 4,500lbs).

Click to expand...

I suspect it is a trade off between the 0-60 time and battery life.How long is the battery warranty? So it could be at first, the paper calculation said it is doable under 6 sec. Then the A123 engineer did a battery life calculation and said cannot do. Back and forth and finalize at a safe number of 6.3 sec. Then software programs in the limit. Someone needs to ask Fisker to confirm.

I was merely checking to see if that Fisker mechanic or engineer(?) is in the ball park with his 3.5 s claim. With ideal 100% efficiency and no wind or wind at the back , it seems possible.

Hehe true. I don't think the Stealth 0-60 time changed at all, just the Sport mode numbers. My understanding from a couple different sources is the new muffler 3.0 system and the desire to keep the emissions low and the interior cabin noise down in Sport were all the reasons why the 0-60 time went from 5.9s to 6.3s.

Nimisys

· #36 · Feb 5, 2012

Part of it is the current draw out of the batteries and heat build up in the inverters. There are limits to how much and how quickly you can pull current from the battery, and they are not that far out of reach in normal usage. You also have the additional heat generated from converting the DC voltage to AC voltage needed for the traction motors. The heat tolerances for the converters is also fairly low: 150F, any hotter and they go into a limp mode.

Sparky168

· #37 · Feb 5, 2012

SoCalGuy said:
Sparky168 said:

SoCalGuy said:

I highly doubt this for more commercial reasons. Firstly, Fisker first advertised that the car could go from 0-60mph in "5.8 seconds"... then it became "5.9 seconds" ... then "6.1 seconds" and now officially its "6.3 seconds." Fisker himself said the car could go 0-60 in "under six seconds"... now he says "about 6 seconds." If it was simply a software tweak, Fisker would have had some "burst mode" or "nitro mode" option on the Fisker controls to go 0-60 in 5 seconds or 4 seconds or whatever... so they could market the car as being able to go 0-60mph in "under 5 seconds" or "4.5 seconds" or whatever. You doubt that? Recall how many times Fisker kept saying "100mpg" in their adverts, interviews, etc... which became "67 mpg".... and now its "52mpg." It can't just be a software thing - its gotta be related to the unanticipated weight of the car and other mechanical/electrical issues (recall the car was initially expected to weigh around 4,500lbs).

Click to expand...

I suspect it is a trade off between the 0-60 time and battery life.How long is the battery warranty? So it could be at first, the paper calculation said it is doable under 6 sec. Then the A123 engineer did a battery life calculation and said cannot do. Back and forth and finalize at a safe number of 6.3 sec. Then software programs in the limit. Someone needs to ask Fisker to confirm.

I was merely checking to see if that Fisker mechanic or engineer(?) is in the ball park with his 3.5 s claim. With ideal 100% efficiency and no wind or wind at the back , it seems possible.

Click to expand...

Hehe true. I don't think the Stealth 0-60 time changed at all, just the Sport mode numbers. My understanding from a couple different sources is the new muffler 3.0 system and the desire to keep the emissions low and the interior cabin noise down in Sport were all the reasons why the 0-60 time went from 5.9s to 6.3s.

My theoretical calculation is for the stealth mode.
The battery power is 369 KW. This is 20% higher than the motor output power of 400 HP or 298 KW. In another way, with an 81% motor input to output efficiency, the battery can deliver full 400 Hp at the motor output (369 KW x .81 = 298 KW).
Recalculate the numbers with 5,500 lb as suggested by ct-fiskerbuzz. The horsepower required is 256KW or 344 HP. Assume the wind + inefficiency adds 16%, horsepower required = 344 HP x 1.16 = 400 HP, or 256 KW x 1.16 = 297 KW.
So doing 0-60 in 3.5 sec in stealth mode is possibble

.

SoCalGuy

· #38 · Feb 5, 2012

Sparky168 said:
SoCalGuy said:

Sparky168 said:

SoCalGuy said:

I highly doubt this for more commercial reasons. Firstly, Fisker first advertised that the car could go from 0-60mph in "5.8 seconds"... then it became "5.9 seconds" ... then "6.1 seconds" and now officially its "6.3 seconds." Fisker himself said the car could go 0-60 in "under six seconds"... now he says "about 6 seconds." If it was simply a software tweak, Fisker would have had some "burst mode" or "nitro mode" option on the Fisker controls to go 0-60 in 5 seconds or 4 seconds or whatever... so they could market the car as being able to go 0-60mph in "under 5 seconds" or "4.5 seconds" or whatever. You doubt that? Recall how many times Fisker kept saying "100mpg" in their adverts, interviews, etc... which became "67 mpg".... and now its "52mpg." It can't just be a software thing - its gotta be related to the unanticipated weight of the car and other mechanical/electrical issues (recall the car was initially expected to weigh around 4,500lbs).

Click to expand...

I suspect it is a trade off between the 0-60 time and battery life.How long is the battery warranty? So it could be at first, the paper calculation said it is doable under 6 sec. Then the A123 engineer did a battery life calculation and said cannot do. Back and forth and finalize at a safe number of 6.3 sec. Then software programs in the limit. Someone needs to ask Fisker to confirm.

I was merely checking to see if that Fisker mechanic or engineer(?) is in the ball park with his 3.5 s claim. With ideal 100% efficiency and no wind or wind at the back , it seems possible.

Click to expand...

Hehe true. I don't think the Stealth 0-60 time changed at all, just the Sport mode numbers. My understanding from a couple different sources is the new muffler 3.0 system and the desire to keep the emissions low and the interior cabin noise down in Sport were all the reasons why the 0-60 time went from 5.9s to 6.3s.

Click to expand...

My theoretical calculation is for the stealth mode.
The battery power is 369 KW. This is 20% higher than the motor output power of 400 HP or 298 KW. In another way, with an 81% motor input to output efficiency, the battery can deliver full 400 Hp at the motor output (369 KW x .81 = 298 KW).
Recalculate the numbers with 5,500 lb as suggested by ct-fiskerbuzz. The horsepower required is 256KW or 344 HP. Assume the wind + inefficiency adds 16%, horsepower required = 344 HP x 1.16 = 400 HP, or 256 KW x 1.16 = 297 KW.
So doing 0-60 in 3.5 sec in stealth mode is possibble .

I remember reading somewhere that the effective peak output for the battery is 240hp / 180KW

teslaowner

· #39 · Feb 5, 2012

Well, considering Tesla felt the need to use a battery 3.75 times the size of the Karma's battery to take its 20% lighter Model S from 0 to 60 in 4.4 seconds, it seems unlikely that the Karma can be practically modified for a 3.5 second time.

Also, the Roadster Sport does 0-60 in 3.7 seconds, using a 300hp motor to move the 2723 pound car. It therefore eems unlikely that only 1/3 more horsepower (400hp) can move a car weighing twice as much in even less time.

BTW, note that the Roadster Sport actually puts out less horsepower than the standard Roadster (299 vs 302). Clearly, torque, power delivery, whatever you want to call it, matters more.

Now, jettison that heavy ICE engine and put in some more batteries and upgrade the power electronics, and you might have something there. ;^)

Fabulist

· #40 · Feb 5, 2012

I am not going to argue with Newtonian physics, but as a practical matter, no manufacturer is going to purposely over engineer any part of a car only to limit it by software. There is undoubtedly one component in the
Battery+Generator->Inverter->Motor circuit that cannot handle more power than the maximum stated limit and that could be the inverters, the motors, or even the power cables. So even if you can get the power generation system to liberate more than 300KW, you may end up burning up the inverter, motor, the cables, or something else.

-- Fab.

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