<p>We consider the task of controlling a battery while balancing two competing objectives that evolve over different time scales. The primary objective, such as generating revenue by exploiting time varying energy prices or smoothing out the load of a computation center, operates on the scale of hours or days. The long term objective is to maximize the lifetime of the battery, which operates on a time scale of months and years. These objectives conflict; roughly speaking, the primary objective improves with cycling the battery more, which ages the battery faster. Using an existing model for battery aging, we formulate the problem of controlling the battery under these competing objectives as a convex optimization problem. We demonstrate the tradeoff between the primary objective and battery lifetime through numerical simulations.</p>