20 HP for 30 minutes works out to about 150 W-Hr/kg. Well within the
capabilities of high-quality laptop Li-Ion cells.

The numbers I gave for A123 Systems cells are for the brief run down
the strip. Like the Slurpie, you can do it over and over, but you
must pause a bit between discharges to let the chemicals inside the
battery diffuse back into place.

Heating the cells to 70 C makes a big dent in their cycle life.
(Probably cuts the cycle life by a factor of 5 or more.) The big
discharges make a lesser erosion on cycle life. We don't go very deep
into the total capacity, however, so this helps cycle life just a bit.

At more normal temperatures and currents, you can expect 10,000
cycles before you reduce the cells to 1/2 capacity. Thus, making 40
to 100 passes down the strip per year is just scratching the surface,
even if you are torturing the cells. Under this use, you would need
to replace the pack about every 5 years.

Bill Dube'