VoltBridge builds the battery backup unit (BBU) for three deployment points in the AI rack: a 51.2V LFP rack battery backup shelf, a 1U server bridge module, and a ±400VDC high-voltage shelf on the 800VDC road. One cell platform, one compliance file, three form factors.
Same 21700 LFP cells and the same compliance file, packaged for where the backup has to live: the rack, the node, or the high-voltage bus.
5.12 kWh per shelf, 100A continuous with a 200A 10-second peak, hot-swap service and up to 15 shelves in parallel.
A 1.5 kWh bridge cell that rides inside the node: transfer under 1 ms, five minutes at full load, PMBus telemetry, cold-plate compatible.
11.6 kWh at ±400VDC with 97%-plus efficiency and a dual-bus path to 800VDC racks — built for the high-voltage backup wave.
| Specification | VB-5125 | VB-E3 | VB-H400 |
|---|---|---|---|
| Form factor | 19" rack shelf, 3U | 1U server module | 21" rack shelf, 2U |
| Nominal voltage | 51.2V DC (16S) | 48V / 54V bus | ±400VDC |
| Capacity | 5.12 kWh (100Ah) | 1.5 kWh | 11.6 kWh |
| Cell platform | 21700 LFP | 21700 LFP | 21700 LFP, 416S equivalent |
| Bridge & discharge | 100A @1C · 200A peak /10s | <1 ms bridge · ≥5 min full load | ≥97% efficiency at bus |
| Scaling | Up to 15 shelves in parallel | Per node, one 1U slot | Up to 80kW-class bay |
| Standout capability | Hot-swap shelf service | Cold-plate compatible | 800VDC-ready dual bus |
| Typical application | Rack battery backup for AI / HPC rows and edge rooms | GB300-class GPU node backup | High-voltage racks and the 800VDC roadmap |
All three lines: UN 38.3 tested · IEC 62619 designed & tested · CE marked (DoC available) · 5-year warranty
When you own the rack but not the server: 51.2V LFP shelves drop into 19-inch bays and carry the row through the gap while gensets start.
When a GPU node has to ride a dip on its own: a 1U module on the 48V/54V bus closes onto the rail in under a millisecond.
When the roadmap says 800VDC: ±400VDC shelves with a dual-bus design keep high-voltage racks on the right side of the transition.
Send us the bus voltage, runtime target and rack layout — engineering replies within 48 hours with a sizing note and a sample plan.
Tell us your rack architecture and bridge-time target. Engineering reply within 48 hours, sample units available for qualified projects.
VB-5125 · VB-E3 · VB-H400
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