What is a travel-friendly light alarm or travel-friendly uninterruptable power supply for a light alarm?

I'm looking at moving to a place where electricity may be off at night, and consequently a Philips HF3250 light alarm should still function as a lamp but would forget the time daily.

(Note that I have tried using iPhone apps for this purpose; the light on my phone display hasn't been sufficient for me personally.)

What, if any, uninterruptable power supply options exist that would be small, would have a low power draw, and would give my alarm enough power to not forget the time if electricity is turned off overnight?