Description�� 1) CR1220 Button Cell (Backup RTC Battery)If you mean the tiny coin-cell inside a DVR/NVR that keeps time and settings saved when the device is unplugged, then the “1220” refers to a CR1220 lithium button battery:Form factor: CR1220 (12 mm diameter × 2.0 mm thick)Voltage: 3 VType: Lithium coin cell (non-rechargeable)Purpose: Maintains real-time clock (RTC) and internal settings in DVR/NVR boards when power is off.These are tiny button batteries, not large power sources — they don’t power the whole DVR, just the small internal clock/firmware memory.Examples / Stuff to know:Compatible with many CCTV DVR/NVR brands that use CR1220 battery slots.You can replace it easily when your system loses date/time after power loss (a common symptom).�� How to Identify Your Battery Need✔ If it’s a small round battery inside the motherboard clock backup:→ You need a CR1220 (3 V coin cell).✔ If it’s a large rectangular battery to power DVR/NVR during outages:→ You need a 12 V 20 Ah sealed lead-acid (or similar) battery.�� Quick SummaryBattery TypeTypical UseVoltageNotesCR1220 coin cellDVR/NVR clock backup3 VSmall button battery inside board; non-rechargeable
