The batteries in the Music Pad + are not customer serviceable. The batteries are Nickel Hydride, bundled in 2 separate packs. The built in charger on the printed circuit board charges them. After a full charge the batteries will run the Music Pad set at .5 brightness for approximately 4 hrs. Recharging takes a couple or hours. For the first charge we recommend an 8 hr first charge. The power supply for the Music Pad is all that is needed to run and charge the Music Pad.