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631683-B21 — Network Technical Data

HP · TRANSCEIVER · POWER_CABLE
WHAT YOU NEED TO KNOW
Very common replacement part Capacitors degrade slower than batteries but still lose capacity over time
CABLE LENGTH IS CRITICAL: 660093-001 = 36" (2U+), 654873-003 = 24" (1U)
PRODUCT OVERVIEW

The HP 631683-B21 is a Flash-Backed Write Cache capacitor pack with a 610mm (24-inch) cable, designed for HPE Smart Array controllers in ProLiant Gen8 and Gen9 servers. It provides backup power to the FBWC module during unexpected power loss, ensuring cached write data is safely committed to flash memory. Unlike traditional batteries, the supercapacitor design offers a longer operational lifespan with no scheduled replacement cycles and no temperature-related degradation.

This is the short-cable variant (24") designed for 1U chassis configurations. The long-cable variant for 2U+ chassis is 660093-001 (36"). This is a high-volume replacement part in TPM market as ProLiant Gen8 and Gen9 servers remain widely deployed.

WHERE IT FITS
TRANSCEIVER→ POWER_CABLE→ 631683-B21
SPECIFICATIONS
Part Number631683-B21
ManufacturerHP
FITS THESE MACHINES
HPE ProLiant DL580 G8
COMPONENT DIAGRAM
CAP 72V + - CAP 72V BRACKET TO CTRL CABLE: 610mm ~76 mm CACHE BACKUP | Supercapacitor | Cable: 610mm Connects to RAID controller | | Controller: See controller spec SCHEMATIC: + - 2S2P SUPERCAP PACK TITLE CACHE BATT PN 631683-B21 MFR HP HP Capacitor Pack with 610mm (24 inches)
KEY FEATURES
•
Flash-Backed Write Cache Capacitor
•
610mm (24") Cable Length
Compact cable for 1U chassis installations
•
Supercapacitor Technology
Longer lifespan than traditional batteries — no scheduled replacement cycles
•
Hot-Plug Capable
•
No Maintenance Required
TYPICAL APPLICATIONS
  • RAID cache protection during power loss events
  • Write-back cache enablement for storage controllers
  • Enterprise server data integrity assurance
  • Hot-swap battery/capacitor replacement in production
SUBSTITUTES & CROSS-REFERENCES 2
654873002SubstituteBROKER-VERIFIED
HP Capacitor Pack with 610mm (24 inches) long cable
substitute
660092001SubstituteBROKER-VERIFIED
HP Capacitor Pack with 610mm (24 inches) long cable
substitute
LIFECYCLE

No lifecycle data available.

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FREQUENTLY ASKED QUESTIONS
What is 631683-B21?
631683-B21 is a HP Capacitor Pack with 610mm (24 inches) long cable manufactured by HP. It is classified as a TRANSCEIVER (POWER_CABLE).
What parts can replace 631683-B21?
There are 2 known substitutes for 631683-B21: 654873002, 660092001. Substitute compatibility should be verified for your specific system.
Is 631683-B21 still available?
631683-B21 is currently Unknown.
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PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.