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Old 01-01-2012, 05:09 PM   #59 (permalink)
Ken Fry
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Originally Posted by Ecky View Post
Ken, what do you feel is the smallest battery size one could use in a vehicle like yours and still have a good driving experience? 10 mile range? 5? What is the minimum cost in battery capacity to make this concept work, and what are the disadvantages of using smaller capacities other than the obvious?
Central to the answer for this is that the reasonably-priced lithium phosphate cells are relatively low power output (for a given energy capacity), so that to have adequate power capability, you end up with relatively large energy capacity. Cells like the Kokam lithium polymer cells are higher power output, but expensive, on a $/kWh basis. The higher power output cells are more likely to require active cooling, so there is additional cost involved, in that, too.

If you are building your own vehicle, and willing to watch temperatures and perhaps cut back a little on maximum power, then 20 miles might be a reasonable minimum range for typical large format, high energy cells. 10 miles is probably a reasonable minimum for high power cells.

The number of engine cycles (and the number of operating hours) are reduced with longer ranges. Reducing the number of cycles (even with the same number of hours) is advantageous from emission, wear, efficiency and reliability perspectives. Again, for an owner-built vehicle, 10 miles might be a reasonable minimum, from an engine perspective.
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