A battery is a system, not a watt-hour number.

Cell, module and pack are different product boundaries

A lithium-ion cell supplies electrochemical capacity. A module connects cells mechanically and electrically. A robot battery pack adds interconnects, sensing, protection, switching, fusing, enclosure, thermal design, service interface and often communication. The charger, docking contact and robot power distribution remain additional system elements.

The first RCI power table deliberately includes two smart packs and one Molicel P45B cell. That mixed boundary is a teaching device: the cell’s 45 A claim does not make it a 45 A robot pack. Pack current depends on series/parallel layout, cell matching, temperature, busbars, protection devices, BMS settings and enclosure cooling.

Nominal watt-hours are not usable robot energy

Nominal energy is often voltage multiplied by amp-hours or a manufacturer-stated typical value. Usable energy depends on charge limit, discharge cut-off, current rate, voltage sag, temperature, aging, cell balance and the robot’s minimum bus voltage. DC/DC conversion, compute, standby loads and actuator inefficiency reduce delivered mechanical work further.

RCI labels a calculated 97.9 Wh value for RRC2054-2 as derived from 14.4 V and 6.80 Ah. It is not presented as a runtime measurement. The distinction lets readers reproduce the arithmetic without mistaking it for a tested duty cycle.

Compatibility requires six matching layers

Before a battery, BMS, charger and robot are called compatible, record at least these layers.

• Voltage: cell count, full-charge voltage, cut-off, regenerative ceiling and transient tolerance.
• Current: continuous, pulse duration, inrush, short-circuit protection, connector and conductor limits.
• Communication: SMBus, CAN or proprietary messages, addressing, authentication, alarms and update rate.
• Mechanical: connector keying, pinout, retention, enclosure, impact, vibration and service procedure.
• Thermal: charge/discharge temperature, sensing, derating, cooling and propagation containment.
• Charging and safety: algorithm, contact sequencing, isolation, transport documents and application-specific tests.

What UN 38.3 does and does not establish

UN 38.3 test documentation is important for transport of lithium cells and batteries. It does not by itself prove that a pack is electrically, thermally or functionally safe in a particular robot. The exact model, revision, cell configuration and test summary must match the shipped product.

Application evidence can additionally involve regional product safety, machinery or robot standards, charger certification, EMC, environmental tests and system hazard analysis. RCI links a transport document as one evidence item rather than converting it into a universal safety badge.