UPS+PSU
UPS+PSU
Visit Outervision and utilize their power supply calculator. It provides an approximate estimate of the current system's power consumption. Apparently, it might also include information about a backup option based on the outcome.
Other reputable battery backup resources typically offer calculators to assist in selecting the appropriate backup solution for your requirements and off-grid duration. I have been a supporter of APC as well.
Only someone with a 1000w power supply is required for a 200w system.