Wiktionary
battery-backed
a. 1 (context electronics of a device English) Using a battery to maintain operation when not powered by the main electrical supply (e.g. during a blackout). 2 (context electronics computing English) Using a battery to maintain volatile memory when powered off. 3 (context video games of saved game data English) Written to a volatile memory memory chip in a video game cartridge to maintain the data when not in use.