Ours runs off the house batteries/inverter and doesn't use that much juice to worry about. But like Bob said a wireless Bluetooth speaker is probably an excellent option. There are soooo many different types and price ranges available now (Best Buy, Bed Bath and Beyond, Target, Walmart, etc) and the nice part is that it would be portable, allowing you to listen to music or books while in the shower, at the beach or hanging out under your awning. The newer varieties allow you to use just one speaker, or if you buy another speaker it will pair with the original and provide better stereo.
- Mike