[sirwattsalot]

Performance can mean different things to different people. Spinning the tires and running the batteries out in seconds will impress some. For me the challenge is to go the distance on as little energy as possible. So, this weekend I broke a new personal record with my homebuilt EV. I drove my car 47.7 miles which is 7 miles better than previous test drives. I used the same 36, 100 amp hour LIFEPO4 cells, the same motor, the same road conditions, but one thing was different. I have been experimenting with regeneration, not regenerative braking systems alone, but also other ways to reduce power consumption. The 7 miles was "in the noise" that most people are told to ignore. I could not be happier to get some extra miles without the high cost of extra batteries. My next efforts will be to reduce drag. The car is already very popular at car shows and very practical to drive to work and for shopping. That is the kind of performance that the world needs. In a world starved for energy, use less, go the distance and charge with solar energy.

 

[bsamarah]

Hi can you give more details on how you reduced the noise ? Which noise are you referring to ? Can you also give details on your car ? type weitght and what electronics / controllers you are using ?

Thanks

 

[sirwattsalot]

My car is a 1994 Saturn SC2 which now has an AC50 motor and a Curtis 1238, 3 phase controller with regenerative brakeing. The noise that I have been talking about is really that energy which we disregard as waste. Anything that is less than 100% effecient is wasting some energy. Nothing is 100% and absolutly nothing is overunity or perpetual.
I am not fully prepared to discuss the experimental circuit that I have been working with, however I can discuss the problems that reduce the performance of any motor. Any vibration will result in a loss of energy so careful balencing of the flywheel and/or linkage components will be necessary. Excessive current draw will result in the production of heat and will also rapidly discharge the batteries so careful power management is essential. When the batteries are weak the management of power becomes more difficult. Carefully consider the next four facts. 1) As current is drawn from the batteries the battery voltage will drop sharply. 2) A motor will run faster when supplied with high voltage than with low voltage. 3) A motor that is stopped or running slowly under load will draw more current than a motor that is running at its best speed and at its ideal load.
4) The faster a battery is discharged, the less is the total recoverable energy, or Perket effect.
A motor runs best when supplied with both suffcient voltage and current. Even if sufficent current is available, low voltage will cause the motor to lag. In my car, acceleration requires as much as, 500 amps but at a nice steady 60 mph cruise, current may be as little as 50 amps. As the batteries get weak the trouble is acceleration. If there were no traffic, no traffic lights, no stop signs, no sharp turns, there would be no problem; I could drive at a constant speed from point A to point B. At the car's best constant speed, the range is impressive, but in the real world, getting up to speed after each stop is a problem. The solution comes in the form of several types of regenerative systems. The most common is regenerative braking. One other that has not been widely accepted is called "Regenerative Acceleration." The inventor, Thane C. Heins, has a lengthy explanation of how it works. I frankly don't think that it does work to any great advantage, but people are trying hard to find solutions. My own approach to the problem seems to be working well for me, but I will keep on testing the car before I get too excited.

 

[arklan]

so basically hes using ultra caps to help his acc and reduce voltage sag

id be interested in more details

 

[sirwattsalot]

Power spikes can be damaging and we like steady DC without noise and yet here in lies the solution; a power surge within safe limits to lift the voltage sag. And, yes capacitors. It is a delicate matter to be certain. To accelerate is to draw a surge of energy. You can't draw more than what the supply can give you in an instant.