I’m currently working on some code using the Excel REST API against in SharePoint 2013. If you’re not familiar with it the endpoint can be found at http://server/_vti_bin/ExcelRest.aspx.
If you try to browse the model of a spread sheet you will hit the same limits as file preview does. You cannot preview a spread sheet larger than 10mb. The question is, how do you change this?
Both http://office.microsoft.com/en-us/excel-help/data-model-specification-and-limits-HA102837464.aspx and http://office.microsoft.com/en-us/excel-help/redir/XT103458353.aspx talk about setting this via the Excel Services in Central Admin. But this is not how to do it. You can perfectly well use the REST API and preview files using OWA without Excel Services installed. You do it on the OWA server using PowerShell. If you want to increase from 10mb to 50mb issue the command below followed by iisreset and you’re good to go!
Set-OfficeWebAppsFarm -ExcelWorkbookSizeMax 50