file transfers from XQD card to external drive using iPad

Greetings, I'm looking for a good workflow/app that would allow me to transfer files from an XQD card (reader) to a small external hard drive using my iPad instead of using a laptop. The use case is photography and backing up photos on the road without having to carry a laptop. I don't want to copy to iPad as the files are large and I am doing a lot of shooting on a single trip. Anyone doing the same? Regards, Scott