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  Dec. 13, 2009 10:03 p.m. xci_ed6 Reader

  So I want to build one, but don't currently have the resources. Here's my idea though.

  All motivation is electric, run off a battery. The battery gets charged by an ICE powered generator. The average car can supposedly cruise on 8-10hp. Oversize the generator slightly, maybe 15hp, and it would have the capacity to charge the batteries while cruising, with surge capacity for acceleration supplied by the batteries.

  My major concerns are space, required power. I have no idea what size motor would be needed, so I don't know the surge capacity required. Nor do I know how many batteries would be needed, since I don't know the voltage required for the motor.

  I do know that having the constant RPM generator would allow it to be tuned for maximum efficiency. It would also be easy to integrate a control circuit to start the generator only when needed. Waste heat from the generator could be used to heat the batteries & cabin for cold climates, solving another major issue. Finally, the charger would be on-board, simplifying the plug-in issues normally associated with pure electric power.

  I've heard of this idea being used before, the Hybrid public transportation buses in Cedar Rapids, IA used I4 Isuzu turbo diesel generators, with an electric motor to a two speed transmission spinning the wheels. Maximum RPM was ~60mph in 2nd gear. I don't know of any production cars using this system.

  I was also thinking about the donor vehicle. I think ideally it would be an AWD/4WD, with a longitudinal engine layout. The tunnel would have space for the generator, with the electric motor, mounted transversely, driving only the front wheels. Since it will require fewer batteries than an electric car, they may fit in the engine compartment only, optimizing the utility of the cabin.

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  Dec. 13, 2009 10:40 p.m. patgizz Dork

  seriously?

  have you been under a rock for 6 months or just new here?

  if the latter disregard my confusion

  John Brown wrote:"Safety" is my second middle name, it's right after "Screw".

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  Dec. 13, 2009 10:46 p.m. xci_ed6 Reader

  neither, but all the electric car threads I see here are about electric, not hybrid.

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  Dec. 13, 2009 11:04 p.m. triumph7 Reader

  First, download the 2nd episode of the current season (14) of Top Gear. They build their own electric car. OK, some of it is a good "how NOT to" but you'll see a couple serious things too.
  

  A number to keep in mind is 746. That's the number of watts per horsepower. You can work backwards from there. Determine the amount of power needed from weight, gearing (if any) and desired performance. Most formulas can be used in both directions.

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  Dec. 13, 2009 11:20 p.m. xci_ed6 Reader

  I thought it was 745.7 Really though, I'll check out Top Gear.

  I've built a few electric 'go-karts', but nothing bigger than 180lbs w/o the driver. They ran two-12V batteries in series, and would run ~40mph for ~60 minutes around a circuit. Peak tested speed was almost 80mph.

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  Dec. 14, 2009 11:55 a.m. GameboyRMH SuperDork

  xci_ed6 wrote: I've built a few electric 'go-karts', but nothing bigger than 180lbs w/o the driver. They ran two-12V batteries in series, and would run ~40mph for ~60 minutes around a circuit. Peak tested speed was almost 80mph.

  Wow nice! Tell us moar!

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  Dec. 14, 2009 3:07 p.m. Nashco SuperDork

  patgizz wrote: seriously? have you been under a rock for 6 months or just new here? if the latter disregard my confusion

  What he said.

  Portland, OR | '69 Bug | '05 Saabaru | '95 Impreza | '67 122S | '07 Sky Redline | $2009 AWD Fiero Hybrid | '72 N600

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  Dec. 14, 2009 4:16 p.m. blizazer New Reader

  I'm pretty sure I saw one of these when I was at teh $2009 West Coast challenge.

  Or was that when I was at the $2009 Florida challenge?

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  Dec. 14, 2009 9:24 p.m. xci_ed6 Reader

  GameboyRMH wrote:

  xci_ed6 wrote: I've built a few electric 'go-karts', but nothing bigger than 180lbs w/o the driver. They ran two-12V batteries in series, and would run ~40mph for ~60 minutes around a circuit. Peak tested speed was almost 80mph.

  Wow nice! Tell us moar!

  They were terribly unsafe. 2 wheels in front, 1 in back. 20" bicycle wheels, threaded to MTB hubs with heavy duty spokes, and hydraulic disc brakes (no rear brake). Aluminum chassis, designed by guessing. The lightest cars we built, the driver was part structure. Going around corners, you had to brace your shoulders against the chassis to limit the twisting. Driver was completely prone, steering with a joystick between the legs. Originally the batteries were behind the driver, that led to problems because the axle had to be in front of the drivers feet. There wasn't enough weight up front to steer once the speeds got higher. So we moved the batteries to the front, which also allowed impressive burnouts. Cars lasted ~2 seasons, one lasted 6, but we had to replace the front axle twice. It was 1/8" wall 2" square aluminum tubing, and braking loads would eventually warp it enough to cause issues getting it aligned.

  We made our own spindles from 2" square steel bar. We tried aluminum once, resulting in a catastrophic failure when the car was forced onto a rumble strip to avoid a collision with a yellow car. Rumble strips spelled disaster, anyway, with only 3/4" of ground clearance they always tore up the chassis. We thought it was best that wheels stayed attached, regardless of chassis damage though.

  My last year one of our drivers was bumped into a concrete wall by another car. The homemade crumple zone worked, but he was still injured pretty badly. I blame race organizers who didn't plan for enough hay bales or runoffs (there were none on that corner). I also blame the yellow team (who was also at fault for the rumble strip incident, both times we suspect they had limited or no brake function). The next year the yellow team let a 14 year old girl test drive their car without proper instruction, she died. Since then regulations have slowed the cars down significantly, it is probably a good thing though.

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  Dec. 14, 2009 9:35 p.m. xci_ed6 Reader

  By proper instruction...

  The cars had a hand brake or a foot brake. Either typically used twin circuit go-kart master cylinders. The first couple we used the hand levers from the bicycle brake kit, mounted on the joy stick. All cars had a deadman switch. Hold it down to go, either on the joystick or under one foot. Speed was controlled by a potentiometer, either directly controlling duty cycle, or controlling RMS amperage. If you let off the deadman, you had to zero the pot, then bring it back up slowly.

  The girl went WOT into a fence made of pipe, that was at head level. Witnesses said she was accelerating into it, and did not attempt to turn. A very unfortunate accident, that should not, under any circumstances, have been allowed to happen.
  

  Insurance regulations barred any drivers under 16 or without a license, she had neither. Also, testing areas should be free from obstacles, and new drivers should have been given weak batteries, or had the controller limits set. All of these precautions were SOP for all teams, but they were ignored that day.

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  Dec. 14, 2009 11:01 p.m. Trans_Maro HalfDork

  You can hear the laws of thermodynamics breaking.

  Seriously, you'd be better off putting the fuel for the generator into a modern, efficient engine and getting your horsepower that way.

  Shawn

  Sometimes life leaves a hundred dollar bill on your dresser, and you don't realize until later that it's because it screwed you.

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