[Biostud]

Is it possible to send and receive large files +20mb (podcasts) without having the power connected, when using wi-fi? If so, how?

[RuleOfSines]

Is it possible to send and receive large files +20mb (podcasts) without having the power connected, when using wi-fi? If so, how?

20mb isn't very large, is something going wrong when you are doing it? A specific app telling you that you must be plugged in?

[Biostud]

Podcatcher, also mails with photos attached will first send when attached to power.

[volkerv]

This document describes the limitations a third-party app has to cope with when downloading files:
Background file transfers for Windows Phone

[HeyCori]

And just an FYI, if you have the portico update then you want to set WiFi to always on.