Battery-life is claimed to be up to 10 hours. I made some tests and got close to 9 hours at exactly half volume, which means at volume step 50/100. I also did a test at maximum volume and the speaker turned off on its own after 2:40 hours. Some others report 5-6 hours at higher levels around 2/3, but please keep in mind that for best results you have to control the volume directly from the speaker. Some tend to keep the speaker at maximum all the time and control the volume directly from their streaming device, although this doesn't have any effect on sound quality in case of the Denon Envaya Mini, it has a big influence on battery life and I had done some tests to prove this. At volume step 50/100 I go exactly 8:33 until it turned off on its own, for my next test I left the speaker at 100/100 but reduced the volume on my iPhone instead to get exactly the same loudness as before (I double-checked the loudness with another unit that was set to 50/100). With the Denon Envaya Mini maxed out I suddenly only got 5:11. Just the fact that the speaker was playing at maximum, while still delivering the same medium loudness as before reduced the battery life by 40%. If you remember this, you can definitely improve your battery life, as more and more owners are complaining that they can't reach more than 5 hours at low levels, but I am sure they simply keep their speakers at maximum all the time.