Backup CF cards with no computer

Unfortunately I do not have any experience with apple product. But a quick iphone usb-otg google search revealed this interesting product: Link

For Android you do not need root access to handle USB devices and most phones will support USB-OTG.

But also my phone is not charged during the file transfer but has to run on its own battery. Sadly the USB-OTG standard does not support charging a USB host device.

All the best, Andi