APC RBC21 Replacement Battery

Description

Get reliable UPS backup power with this APC RBC21 replacement battery. This 12 Volt 4.5Ah sealed lead acid battery features recessed terminals, maintenance-free AGM construction and is fully rechargeable. Its non-spillable design allows safe indoor operation and installation in any position except upside down.

Compatibility

The RBC21 is commonly used in compact APC Back-UPS systems designed for home and small office backup power including:

• BF400C
• BF500
• BF500BB
• BF500U

Always verify battery configuration and dimensions before ordering to ensure proper fit.

Key Features

• Sealed AGM Technology – Maintenance-free and spill-proof
• Rechargeable – Designed for reliable standby and backup power
• Safe Installation – Operates in any position except inverted
• Recessed F1 Terminal – Ensures secure connections for UPS wiring
• Durable Construction – Built to deliver long-lasting performance

Specifications

• Voltage: 12 Volts
• Capacity: 4.5 Ah
• Terminal Type: Recessed / RT
• Length: 5.5″ / 140 mm
• Width: 1.9″ / 48.1 mm
• Height: 4.3″ / 108 mm
• Weight: 3 lbs / 1.65 kg
• Data Sheet: WP1221W Data Sheet (PDF)

Performance

• Fully charged and ready to install
• Designed for 3–5 year service life in standby applications

How do I know if this replaces my APC RBC21 battery?

Check your UPS battery label for “RBC21” and confirm the 12V 4.5Ah configuration. This replacement battery is compatible if your UPS matches these specifications and dimensions.

APC™ and all APC RBC part numbers are registered trademarks of American Power Conversion. Part numbers listed on this page are for reference purposes only and do not imply endorsement or sponsorship by APC.