Capacitor based and battery based DC back-up systems both have many advantages and some limitations. Battery based systems provide the longest buffering times and greater flexibility, as batteries can be sized to specific needs of individual application, but they have a small operating temperature range and additional installation requirements. Capacitor based systems have a very wide operating temperature and longer service lifetimes, but provide backup power for shorter periods. Application conditions and requirements will determine the best solution – the backup time and current needed, operating temperature range, and service interval requirements are the primary factors that will guide the customer to the best solution.