BBU Modules & Shelves
From single 1U modules to full 48V backup shelves.
Module Form Factors: 1U/2U Li-ion
BBU modules in this scope are hot-swappable 1U or 2U Li-ion trays that plug into a shared 48V backplane. The Open Rack V3 BBU Shelf specification Rev 1.1 defines the mechanical and electrical interface for these shelves, using a 48V architecture that replaces legacy 12V distribution for GPU trays. That 48V ORv3 shift matters because AI racks now cross 120 kW per cabinet, where 12V distribution becomes impractical.
Sizing typically starts at 1–5 kW per module and scales to 10–20 kW per shelf, so procurement should spec the shelf backplane, connector, and busbar rating together with the module. UL 1973 cell certification and UL 9540A system-level thermal-runaway data are baseline documentation for data center operators. This keeps the rack BBU from becoming a one-off integration risk inside 48V ORv3 rows.
BBU Module & Shelf Specifications
| Parameter | Value |
|---|---|
| Module form factor | 1U / 2U hot-swap Li-ion modules, shared 48V backplane |
| Module power | 1–5 kW per module, depending on cell count and discharge profile |
| Shelf capacity | 10–20 kW per shelf across module slots and 48V bus |
| System voltage | 48V OCP ORv3, replacing 12V distribution for GPU trays |
| Shelf architecture | Open Rack V3 BBU Shelf specification Rev 1.1 mechanical interface |
| Battery chemistry | Li-ion rack-mount cell packs, hot swap without rack de-energization |
| Cell safety | UL 1973 for stationary battery cells |
| System safety | UL 9540A thermal-runaway test data for data center acceptance |
| Shipping | UN38.3 Class 9 sea freight for Li-ion pack transport |
| Sourcing MOQ | 50+ units per shelf SKU for BBU modules |
| Shenzhen lead time | 15–30 days before sea freight, excluding UN38.3 document review |
| Rack compatibility | 48V ORv3 shelves for high-density AI racks crossing 120 kW per cabinet |
Ride-Time Sizing Factors
- AI racks crossing 120 kW per cabinet force per-shelf ride-time modeling, not one-size battery strings.
- Shelf capacity of 10–20 kW sets module count per 48V bus before N+1 or N+N redundancy.
- 48V ORv3 replaces 12V for GPU trays; modules must match ORv3 shelf connector and busbar ratings.
- UL 9540A thermal-runaway data and UN38.3 Class 9 sea freight add compliance and logistics buffer to build plans.
Battery Shipping & UN38.3
BBU battery modules are Class 9 dangerous goods and require UN38.3 test reports before ocean freight. Expect 15–30 days of production lead time from Shenzhen once shelf SKUs are frozen, and contract only with suppliers that provide UL 1973 and UL 9540A documentation with the pack. BBU sourcing MOQ is usually 50+ units per SKU, which makes prototype and pilot volumes more expensive on a per-unit basis.
Because UN38.3 Class 9 sea freight cannot be consolidated with non-battery rack hardware under all forwarder rules, separate the BBU shelf order from PDU and busway shipments at quotation stage. A complete shipping data package should include the UN38.3 test summary, MSDS, and Class 9 label documentation. This avoids customs holds and keeps the 48V ORv3 deployment schedule intact.
Source 48V Backup as a System
Spec the 1U/2U module, shelf backplane, and UN38.3 sea-freight documentation as one package—DC Power matches audited Shenzhen suppliers for UL 1973/UL 9540A BBU builds.
