Quote:
Originally Posted by bennelson
Anyone have some good links for other DIY Hybrids? Please post them here!
If I want to be able to "cruise" at 55mph+ and have the ability to do that at least some of the time on the motor, instead of the engine, I'll need to know how many horsepower are required to do that.
Can anyone help with some horsepower calculations? For now, let's assume that we want to use either a VW Rabbit Pickup, a Subaru Outback stationwagon, or Chevy S10 pickup truck. How many HP are needed to push those vehicles down the road at 55mph? Then we can find a motor - AC, DC, or brushless DC powerful enough to do that. We also need to figure in the RPM range of the motor for how it would be connected to the vehicle, and the gear ratio required. Does anyone have a link for a good HP calculator?
Once we figure on a motor, a matching controller can be found/bought/built to go with it.
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The site
power calculator is pretty good, just plug and chug the specifics (Cd, Crr, etc) of each vehicle.
In terms of the specific design, I'd shy away from a caddy because of the limited carrying capacity (~1000lbs IIRC). By the time the driver, motor, controller and rear end are in there you'll only have enough weight for about 25 miles of electric range.
Given LA batteries to start out with I think a better bet is something like a basjoos style compact body on a 4wd pickup truck frame. Put an old VW diesel engine in up front and hang a big DC motor behind the transmission. If someone is an absolute whiz with shift linkages, or if we could somehow adapt or create an automated shifter, we could shave off a hundred + pounds and increase overall efficiency by mounting the diesel drivetrain transversely, and doing the same to the electric but with a multispeed trans bolted to that as well. Old four speed manual transaxles don't weigh more than about fifty pounds or so, compared to the couple hundred a RWD drivetrain weighs, and multispeed transmissions can significantly increase DC motor efficiency at lower speeds/higher loads.