Keep battery powered pathlights turned on

Is there any way to turn a battery powered pathlight ON and keep it on for longer than 15 minutes? Unfortunately, we have to use battery powered lights in our front yard because 1) we live in Seattle and 2) most of our pathway is in deep shade. I learned the hard way that you can't put battery powered lights on a light schedule (after I bought a bunch of them, installed them and found you can't do that) but I would like to turn them on and keep them on for a period of time each night before going to bed. Is this not possible? If not, I guess they're all going in the trash and that was a monumental waste of money.