865408-B21: HPE 500W Flex Slot Platinum Hot Plug Low Halogen Power Supply Kit

Also listed as: 865408-001, 866729-001, 865399-201, DPS-500AB-13 A · made by Delta Electronics

An energy-efficient 500-watt hot-pluggable power supply certified for 80 PLUS Platinum efficiency (up to 94%) in the HPE Flexible Slot form factor. Sized for single-socket and lightly configured dual-socket servers across ProLiant Gen9, Gen10, Gen10 Plus, and Gen11 platforms, it minimizes idle power consumption while providing N+1 tool-less redundancy. Second-hand units should be tested for silent fan operation, intact latching mechanisms, and clean backplane connector pins.

Specifications

About the 865408-B21

865408-B21 is HPE's 500W Flex Slot Platinum Hot Plug Low Halogen Power Supply Kit. Rated for 80 PLUS Platinum efficiency (up to 94 percent electrical conversion efficiency), it is the entry-tier power supply option in HPE's standardized Flexible Slot architecture. Built specifically for single-socket edge servers, dense single-processor compute nodes, and entry dual-socket workloads where higher-wattage supplies operate below their peak efficiency curves, it provides right-sized power delivery with tool-less hot-plug redundancy.

Compatibility

This power supply is compatible with any HPE Flex Slot bay found on ProLiant Gen9, Gen10, Gen10 Plus, and Gen11 servers, such as the DL325 Gen10 Plus, DL325 Gen11, DL360 Gen10, and DL380 Gen10. It accepts universal AC input voltages from 100V to 240V AC and connects via a standard IEC C13 power cord. Both power supplies in a redundant server configuration must have matching wattage and efficiency ratings; mixing a 500W unit with 800W or 1600W units is not supported by HPE power management firmware. The option SKU is 865408-B21, with spare part number 866729-001 and assembly number 865399-201.

How to identify a genuine unit

A genuine 865408-B21 module bears an HPE manufacturing label indicating option code 865408-B21, spare part number 866729-001, assembly number 865399-201, and the 80 PLUS Platinum certification badge. When booted inside a ProLiant chassis, iLO recognizes the supply under Power Management, reporting active wattage draw, input line voltage, and authentic HPE firmware revisions. Aftermarket units lacking authentic HPE EEPROM programming will fail to report complete telemetry and may trigger system health warnings.

Buying used

When buying second-hand 500W Flex Slot power supplies, verify that the rear card edge contacts are free of scorch marks or copper delamination. Inspect the internal exhaust fan for bearing rattle or dust blockages, and confirm that the green status LED illuminates steadily under load. Check that the quick-release lever and retention clip lock securely into the server chassis cage to ensure steady blind-mate backplane seating.

Reference prices (last 14 days, updated 2026-10-27)

Prices seen on public listings on the dates shown, before tax and shipping. Not an offer.

Fits these models

• HPE ProLiant DL380 Gen10
• HPE ProLiant DL380 Gen10 Plus
• HPE ProLiant DL360 Gen10
• HPE ProLiant DL360 Gen10 Plus
• HPE ProLiant DL325 Gen10 Plus v2
• HPE ProLiant DL325 Gen11
• HPE ProLiant ML350 Gen10

FAQ

Sources

• HPE Flexible Slot Power Supplies QuickSpecs, checked 2026-10-27