Altaro is a relative new player in the field of backup for Hyper-V. It’s Hyper-V Backup version 3 product is targeted at Small and Medium Businesses. It offers all the common features which a backup solution needs. There is a free, standard and Unlimited edition available. The free version is limited to making backup’s of 2 VM’s.
An alternative , rudimentary but free method of saving Hyper-V virtual machine data is by exporting the virtual disks. Altaro offfers a Powershell script for free which can automate the process of creating exports. Read more about it here.