Earlier last year my University house mates and I had house party, in order to provide ample volume and substantial bass I decided to up upgrade from a pair of bookshelf speakers to an all in one, easy to carry sound solution. At the heart of the boombox is a 200W RMS car stereo amplifier, which is more than capable of driving the twin 75W mid/bass drivers.
The system has a 9AH sealed lead acid (SLA) battery, a mains powered battery charger and a high current 12V switch mode power supply in the form of a 203W xbox power supply. A large triple throw rocker switch allows the desired power source to be selected and the smaller rocker switch puts the xbox power supply in sleep mode or awakens in depending on the position.
When a powered IEC (kettle cable) is inserted, the battery management system immediately begins to charge and then maintain the level of the battery.
This project was documented on Instructables.com, click the button above to visit the page.