Alfresco is always on the forefront of modernizing their grilling technology. Their ignition system is certainly one of these components. Early Alfresco AGBQ Grills used a AA Battery push button ignition then they moved onto the 9 volt two or four spark module (depending on the grill) and now the ignition system is completely electronic.
To change the battery in your AGBQ and second generation (2011 and forward) LX2 Grills, remove the drip tray. Underneath the drip tray will be a black round battery cap you unscrew and replace your battery.
In the first generation LX2 Grills (2010 and lower), your grill had a cooling front control panel. You simply lift up the front control and tilt towards you. The battery caps will be located on the right of the grill in all model grills and the 42 & 56 have a left as well.