Introduction 
You can continue to use mBPS-d2s with the use of a battery. There is no need for extra recharging if connecting an adapter for charging to the rear.
There are two packs of built-in batteries with a control circuit that automatically controls charging and output by sensing the amount of each battery pack. That is, an undercharged battery pack gets recharged; an overcharged battery pack is used  as an external power supply.
The front LED displays the state of such operation, and the front power switch can switch on or switch off the output power supply.


Features
- Two Li-ion battery pack
- Automatically rechargeable


Specification

- Power input for charger
  Input voltage : +9Vdc
  Input Current : 2A

- Power output
  Output battery voltage : +6.5Vdc~+8.4 Vdc
  Maximum output current : 1.5A

- Indicate LED
  Low battery x 2 , Charge x 2, Output x 2

- Battery Packs
  2S1P 2200mA Li-ion softpack x 2
  Include protection module for over charge,
  short circuit, over discharge


Other
The very renowned audio website had been reviewed at sMS-1000, here is the link ,
http://www.computeraudiophile.com/content/441-sotm-sms-1000-audiophile-music-server-review/