If you decide to add a Google Map to an accordion element, please check the information below in order to have it working properly.

1. Add the Accordion and Google Maps elements using the Vamtam Drga & Drop builder: 

You can check this guide for more reference: Guide to VamTam Drag and Drop Builder / Visual Composer

2. As the Google map needs trigger to resize when we put it on accordion, tab, or modal, please add the code below to the Custom JS area in VamTam > General settings:

jQuery( function() {
    jQuery( '.pane-wrapper' ).on( 'accordionactivate', function() {
        jQuery( '.google_map' ).resize().each( function() {
            google.maps.event.trigger( this, "resize");
        } );
    } );
} );

You can check this guide for details: How to add custom CSS / PHP code or modify the theme code ?

Sources: http://stackoverflow.com/questions/32086229/google-maps-not-work-inside-bootstrap-accordion