Can you let me know if there is a limit to the number of completed surveys that can be stored on a device offline before connection to the Internet and upload to the SurveyManager. In this instance it is an iPad 2 survey with about 20 questions and up to 400 completed surveys may need to be held on the device prior to upload.
The limit depends on how much storage space you have on the device and whether you are capturing Multimedia. For 1 survey response for a 20 Question survey using an iPad, the file size is ~2KB (without multimedia). The same survey capturing 1 picture the file size is ~1MB. So unless you are capturing a lot of Multimedia you should not have an issue with 400 completed survey stored on the device.