FWIW I just bought a "Mokcao Power + " speaker/battery for our Echo Dot. The Mokcao has a 5 amp battery, so will power the Dot and play music for five or so hours (I have not verified this) before needing a charge. It does not sound as good as the Echo or Echo 2 (less base), but is still pretty good. Prior, I had bought an "Alexa Enabled" cordless speaker from Menards and found out, you have to push a button on it to get it in the Alexa mode. Pretty useless when listening to Pandora in the shower and wanting to skip to new song. Which prompted the quest for a device that uses a true Echo as the AI. There are also battery packs for your full size Echo to make it portable, but I had a Dot which wasn't getting much use.