What precautions have you taken incase of a power outage where you keep your ball pythons?

As most of you know, the proper temperatures for these snakes is of utmost importance for their survival.

I am trying to find suitable back up power for my snake racks and am considering this one.
http://www.ebatts.com/part_852-1807.aspx

Does anyone know if this unit will work well? If not, can you point me in the right direction?