Paper C sets out the evidence programme for a bed or hoist battery: the device-level standards IEC 60601-2-52 and ISO 10535, electrical safety and EMC, cell safety under IEC 62133-1, transport evidence, and the cycle-aging tests that justify a multi-year service life in daily care use.

The Standards Stack

• IEC 60601-2-52 — particular requirements for medical beds (2009+A1:2015; restructured IEC 80601-2-52:2026 for adult beds), including operability of critical positioning functions after loss of external power.
• ISO 10535 — hoists for transfer of disabled persons: requirements and test methods for mobile, standing and bath hoists, defining the lifting cycle used in endurance testing (China adopts the parallel GB 24436).
• IEC 60601-1 / 60601-1-2 — general safety and electromagnetic compatibility; actuator drives and chargers must not disturb, or be disturbed by, nearby medical equipment.
• IEC 62133-1 (nickel cells/packs) and UN 38.3 for transport.

Safe-Lowering and Cycle Endurance

The defining test is functional rather than electrical: at full rated load, with an aged battery at end of life, the bed must still complete its emergency/CPR lowering and the hoist must still raise and lower the patient the declared number of cycles. Inspection protocols for hoists require on the order of 50 consecutive full-load lift cycles from a full charge; commercial declarations cite 40 cycles per charge. The test matrix crosses patient load (empty, average, safe working load — e.g. 250 kg-class beds, 175–300 kg hoists), battery age, temperature and simultaneous actuator use, recording controller cut-off voltage and any mid-move stoppage. Actuator duty limits (10 % duty, 2 min/18 min) are respected rather than overrun.

Environmental and Cell Safety

Beds and hoists live in wipe-down, wash-down environments: handsets and actuators carry IPX6-class protection, and the battery compartment must tolerate cleaning fluids and humidity. IEC 62133-1 validates the nickel cells themselves — external short at ambient and elevated temperature, prolonged overcharge, forced discharge, mechanical and thermal cases — demonstrating the controlled-vent failure mode that keeps an intrinsically safe chemistry safe beside a dependent patient. UN 38.3 clears shipment of replacement packs to hospitals and dealers.

Aging and Replacement Planning

NiMH reaches 80 % after roughly 500–1000 cycles depending on depth and temperature; hoist manufacturers publish ~500-cycle expectations and six-month recharge guidance for stored units. Development combines cycling at the real daily lift count with elevated-temperature storage to set a calendar-and-cycle replacement rule, so preventive maintenance swaps the pack before a lift fails during a transfer. Because NiMH fades gradually, trending of "lifts per charge" gives early warning.

Failure Modes to Design Out

• Mid-raise cut-off — inrush sag in aged, high-resistance cells; prevented by resistance binning and worst-corner validation.
• Dead backup after long float — self-discharge; prevented by low-self-discharge cells and maintenance charging.
• Cleaning ingress — prevented by sealed compartments and IPX6-aligned integration.
• No safe lowering — prevented by explicit IEC 60601-2-52 power-interruption testing at end of life.

Weijiang Power

Weijiang Power supplies high-rate NiMH cells and custom bed/hoist packs with IEC 62133-1 and UN 38.3 evidence, welded surge-rated construction and support for ISO 10535 cycle and IEC 60601-2-52 power-interruption validation. Send your actuator trace, safe working load and cycle target and we will engineer the pack and its documentation together.