Be sure you use a BIG heat sink to mount that transistor. Flowing 15 amps across the emitter/base junction will cause a deadly amount of heat buildup, unless it's able to dissipate the heat quickly. You might want to consider using two transistors in parallel to minimize the loss due to voltage drop, and share the load.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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