CAPABILITIES · BBU

BBU Battery Backup Units

BBU battery backup units protect AI servers from grid faults with 48V rack-level power, meeting OCP ORv3 requirements.

Why BBU backup is now standard on AI racks

A single AI rack now crosses 120 kW per cabinet, according to Wedbush 2026, which means a voltage sag or 200 ms interruption can reset hundreds of GPU training steps. Liquid cooling is mandatory at that density, but rack-level 48V battery backup is what keeps the compute domain alive during the gap before generator or grid stabilization.

OCP Open Rack V3 BBU Shelf spec Rev 1.1 defines a 48V architecture that replaces the older 12V bus for GPU trays. Procurement teams sourcing from Shenzhen can specify 1U/2U Li-ion modules that slot into the shelf, with UL 1973 cell-level safety and UL 9540A fire propagation testing already in the compliance file.

BBU parameter matrix

ParameterValue
StandardOCP Open Rack V3 BBU Shelf spec Rev 1.1
Output architecture48V DC, per ORv3 (replaces 12V GPU tray bus)
Module form factor1U / 2U hot-swappable modules
Module power range1–5 kW per module
Shelf power range10–20 kW per shelf, scale with parallel racks
Cell chemistryLi-ion LFP with stable thermal profile
Battery safetyUL 1973 (battery system standard)
Fire propagationUL 9540A (cell, module, unit levels)
TransportUN38.3 Class 9 dangerous goods for sea freight
MOQ / lead time50+ pcs, 15–30 days from Shenzhen
DETAIL

Module vs shelf packaging

When you import battery backup from Shenzhen, shipping and certification are split between the field-replaceable module and the shelf that hosts it. Modules are the UN38.3-tested dangerous goods; shelves are mechanical and power-distribution assemblies.

  • Module: 1–5 kW, hot-swap, UL 1973 + UL 9540A tested
  • Shelf: 10–20 kW, OCP ORv3 Rev 1.1, 48V bus
  • Ship modules as Class 9; shelf can move as general cargo
  • Spare inventory: keep modules local, shelf per rack row
BBU battery shelf with modules

BBU technical deep dives

BBU modules

BBU modules

1U/2U Li-ion battery modules, 1–5 kW, hot-swappable for ORv3 racks.

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BBU vs. UPS

BBU vs. UPS

48V rack backup vs central UPS: latency, efficiency, footprint, cost.

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OCP ORv3 spec

OCP ORv3 spec

Rev 1.1 48V architecture, shelf mechanicals, and compliance requirements.

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Frequently asked

UL 1973 covers the battery system, UL 9540A validates fire propagation, and UN38.3 is required for Class 9 sea freight. UL 62368-1 applies to the power electronics around the PDU/PSU path.
No — ORv3 moves the GPU tray to a 48V bus, so the shelf, busbar, and power supplies must be specified together. Retrofits require a rack-level conversion or a new ORv3 tray.
BBU modules typically have a 50+ unit MOQ and 15–30 day lead time. UN38.3 Class 9 classification means sea freight with special dangerous-goods documentation.

Spec BBU modules and ORv3 48V shelves

Audited Shenzhen manufacturers, UL 1973/UL 9540A documentation, and UN38.3 logistics — one engineering conversation.

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