Re: More Dolphin information

[Seth <vze3v25q@verizon.net>]

One note: I think you mean 250V and 10 volts per module. Or 1.67vpc.

1)
200 battery amps at 250V is 50kW. Or about 67hp at the motor assuming
100% efficiency. 67 x.85 (motor/ contorller eff.) x0.97 (gears) is about
55 hp to the tires. Are you sure you can pull 200A at highway speeds? If
it is geared correctly you should be above base speed and I suspect the
battery current will fall below the peak. I suspect you will draw max
current between 25-35mph, but this is just a hunch. So I would expect
you to draw something like 120-160A at highway speeds. Assuming the peak
is 200A at base speed.

2)
Regen is not 100% efficient, ther are motor, controller, cabling and
battery losses involved in putting energy back into the motor. Coasting
doesn't incur those losses. So coast if you can, regen as long and
slowly as you can if you need to slow down (don't tailgate and do plan
ahead) and use the brakes as little as is practical and safe.

3)
Slower up hills is a mixed bag. *Mostly* slower is better. But if you
are going really slowly (perhaps 10-15 mph), then you can be in a less
efficient mode for the motor, despite drawing less current and having
less air drag. The dynamic range for AC induction is good, but not
infintite and the efficiency can fall off at either end. Current AC
drives and energy systems make *single gear ratio* AC drive EVs a
compromise between range, starting torque, battery mass, motor
efficiency and top speed. 

Seth

Christopher Zach wrote:
> 
> The Dolphin controller appears to have two cut-off's. The system will not
> draw more than 200amps at a time from the batteries, and the system will not
> draw the batteries below 350 volts (10.0 vpc).
> 
> Typical highway motoring currents are around 60-70amps at 290-300 volts.
> Flooring it doesn't seem to do much more than drive the amps up to 150-200;
> the same results can be gotten by gently accelerating and going for accel on
> downhills. This might be a limit of the single gear concept.
> 
> Is there a "tip list" for optimal EV driving anywhere? One question I have
> is which is better: A bit of regen (which slows you down with your foot off
> the pedal) or coasting (putting the car in neutral)? Is it better to let
> speed decay a bit on hills, or keep speed constant with some power?
> 
> Chris

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