by The_Toecutter » Fri 05 Mar 2010, 16:53:15
I am very impressed by your Fiero. You are much further along in a much shorter amount of time than I am. You will probably get around 50 miles range @ 60 mph to 100% discharge. The Fiero is a heavy car with so-so aerodynamics. It's mid-engined layout is to die for, however. You should seriously consider a GT bodykit for drag reduction to extend the range you will have significantly.
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')Do you think that battery is up to the task? Kind of low C rates, though I suppose at 320 volts you won't be pulling high battery amps too often.
If I go with that setup, I am intent on limiting the battery to ~250A. Even with this limitation, the Zilla could still output 1,000A to the motor, it's just that the battery will be the limiting factor in the maximum horsepower that the motor will output, and not the motor itself(which will be limited to 170V, but with that battery, will not be able to have 1,000A @ 170V).
This still means 220 lb-ft of torque starting at 0 rpm, even if the setup were to instead use a meagre 72V Trojan T105 pack(it would then just be limited to about 30 hp before the torque started to reduce as an increasing function of speed); try getting that torque with a low current AC setup ~300V. Even with a modest 80 hp peak at the motor, 0-60 mph < 8 seconds will still be possible thanks to that LiFePO4 battery being much lighter than the lead acid packs I had considered for it, keeping the final weight of the car around 2,000 lbs; I'm every bit intent on taking Corvettes off the line up to about 30 mph, but insufficient traction will probably prevent me from doing that.
Even with that horsepower limitation at the motor, the bodywork on that car for drag reduction will still allow a top speed ~130 mph with the right gearing so as not to draw more than 65 kW from the pack at that speed(The motor would be at much greater risk of overheating at that speed than anything going wrong with the battery, if the published specs are true, and in the conversions those packs are in, they seem to be. I may find some way to get better cooling to the motor so that a speed of at least 115 mph could be maintained indefinately).
The ADU1B LeMans Spitfire only needed 75 horsepower from its 4-cylinder engine to do 130 mph. This also means ~100 Wh/mile at 60 mph will be possible; Reverend Gadget has achieved this efficiency in his Spitfire conversion *without* any special attention to aerodynamics, other than throwing a GT6 body on it, although he did use tires with a Crr of around 0.006 and his conversion didn't exceed GVWR.
The reason I am seriously considering that pack over the more powerful Thunderskies? A built in BMS. I want this pack to last a very long time after things collapse here in the states.
That thing will be an awesome canyon carver when finished...
The unnecessary felling of a tree, perhaps the old growth of centuries, seems to me a crime little short of murder. ~Thomas Jefferson
