48V · AI BACKUP

RackBridge 48V — the rack-side ride-through module

Name: RackBridge 48V LIC Hybrid Supercapacitor Module
Brand: CapStack

RackBridge 48V is a 48.6 V-class LIC hybrid supercapacitor module for the millisecond tier of AI server backup. It absorbs GPU load steps in 1–50 ms while the battery BBU carries seconds to minutes and the grid ramps in 1–90 minutes. Laser-welded busbars, per-cell telemetry and a test report in every box.

48.6 V

class · 16S

166 F

±5% sorted

130 A

continuous

1–50 ms

transient tier

Request the Datasheet

RackBridge 48V LIC supercapacitor module standing in a data center power shelf, cyan status light on

At a glance

Eight numbers that decide the design

48.6 V

Rated voltage · 16S

Sixteen 3.8 V LIC cells in series on a weldable-terminal format.

166 F

Capacitance class

C/ESR dual-parameter sorted to a ±5% module window.

130 A

Continuous · 25 °C

Natural-air rating; surge class above 500 A for sub-5 s events.

1–50 ms

Response tier

The window where GPU current steps would otherwise trip the rack.

A / P

Balancing

Active or passive per module, with module-to-module auto-balancing.

CAN

Telemetry · 2.0B

Per-cell voltage plus NTC temperature on the bus; three-level alarms.

−40 °C

Cold start

Operating envelope −40 … +65 °C without preheating.

15-yr

Design-life class

Sealed-shelf, maintenance-free posture for rack programs.

Datasheet

RackBridge 48V full specification

Numbers below are the module-class ratings we test against before a serial number ships. Application-specific deratings and bus configurations are confirmed in the RFQ cycle.

Parameter	Value
Rated voltage	48.6 V class (16S × 3.8 V LIC cells)
Capacitance class	166 F module class, C/ESR sorted to ±5%
Cell voltage window	3.8 V hybrid cells, usable down to 2.5 V per cell
Cell ESR (DC)	From 0.47 mΩ, large-cell LIC format
Continuous current	130 A at 25 °C, natural air
Surge current class	> 500 A for events under 5 s
Response tier	1–50 ms transient absorption
Balancing	Resistive / active / passive; module-to-module auto
Telemetry	Per-cell voltage + NTC temperature, CAN 2.0B
Alarms	Over-charge / over-discharge / over-temp, error signal output
Sleep drain	< 20 µA
Insulation / hipot	AC 2000 V for 1 min
Operating temperature	−40 … +65 °C
Cycle life class	500,000+ cycles in a 3.5 → 2.5 V window
Terminals	Laser-welded copper busbars on weldable-terminal cells
Certification route	UL 810A cell route · IEC 62391 methods · CE DoC
Shipping documents	UN 3499 Class 9 · IATA A186 / PI 971

RackBridge 48V module mounted inside an AI server rack power shelf beside PSUs

Rack integration

One shelf, one module, no cabling spaghetti

A GB300-class NVL72 rack draws 132–142 kW and can shift that load in milliseconds. The published architecture answers with storage inside the power supply — 65 J per GPU, with capacitors taking roughly half of PSU internal volume — and rack-integrated storage cutting peak grid demand by up to 30%.

RackBridge 48V is the module form of that millisecond tier. Welded busbars replace harnesses, the CAN node reports every cell to the shelf controller, and the three-tier chain stays honest: LIC for 1–50 ms, BBU for seconds to minutes, grid generation for the 1–90 minutes it needs to catch up.

See the rack power architecture →

FAQ

What integrators ask first

They are different tiers of the same chain, not competitors. The LIC module covers 1–50 ms transients — the window where GPU current steps would otherwise collapse the bus. The battery BBU carries seconds to minutes, and the upstream UPS or HVDC plant bridges the 1–90 minutes the grid needs to ramp. Sized together, the BBU never sees the first spike, which is what ages it.

Cycle life follows the voltage window you discharge into: 500,000+ cycles in a 3.5 → 2.5 V window versus roughly 50,000 cycles across the full 4.0 → 2.5 V swing. Most rack programs run a shallow window and spec a 15-year design-life class with no scheduled maintenance, then verify against the per-module test report that ships with every unit.

Cells follow a UL 810A route and modules are tested to IEC 62391 methods; the supply chain carries RoHS / REACH / WEEE statements and a CE Declaration of Conformity is available per shipment. For transport, everything above 0.3 Wh leaves with UN 3499 Class 9 paperwork on the IATA A186 / PI 971 air basis.

Row of LIC supercapacitor modules charging on a dark test bench

Start the conversation

Send your rack power profile. Get a number back.

Within 48 hours you receive a cell count, a capacitance class, a lead time — and the test-report format that ships with every RackBridge serial number.

Get a Quote