In my Mojo notes I have this code. I can't confirm that it still works but worth a try.
For accordion Change to:
--------------------------------------------
<div class="collapsed-accordion">
Put below accordion code:
--------------------------------------------
<script type="text/javascript">// <![CDATA[
$('div.collapsed-accordion').accordion({active:false, collapsible:true, autoHeight:false, fx:{opacity:'toggle',duration:'fast'}});
// ]]></script>
For tabs
---------------------------------------------------------------------------
<script type="text/javascript">
// MAKES TABS COLLAPSE ON DEFAULT
// <![CDATA[
$('.tabs').tabs({collapsible: true, active: false });
// ]]>
</script>
Beginning with mojoPortal 2.3.5.5, if you want to make the same sort of change skin-wide, you can do so by modifying ScriptLoader in the Layout.Master file for your skin, and adding JQueryAccordionConfig=[parameters]. To continue the example of a closed accordion widget, the final ScriptLoader line would look something like this:
<portal:ScriptLoader ID="ScriptLoader1" runat="server" IncludeSizzle="true" JQueryAccordionConfig="{active:false, collapsible:true, autoHeight:false, fx:{opacity:'toggle',duration:'fast'}}" />