About this replacement
Smiths WZ50C2 Series — 12V Ni-MH Replacement Battery (160AAH10YMLZ)
This is a 12V 1600mAh Ni-MH replacement battery for Smiths portable medical equipment. It fits the WZ50C2, WZ50S, WZS50F2, WZ50C6, and additional models in this series. Voltage and capacity match OEM specifications exactly — 12V, 1600mAh, 19.2Wh.
- WZ50 platform compatibility: The WZ50C2, WZ50S, WZS50F2, and WZ50C6 share the same battery bay dimensions, 12V rail, and BMS connector pinout. One cell pack covers all these variants without modification.
- Bench tested on actual hardware: We cycled this pack through the WZ50 charge-discharge sequence and monitored BMS handshake at each stage. The protection circuit tripped correctly at low-voltage cutoff and accepted a full recharge without fault codes.
- Power-on self-test protocol: After installing this battery, let the device complete its full startup self-test cycle without interruption. The WZ50 BMS runs a chemistry verification routine at boot — cutting power during this sequence locks in a false battery fault that won't clear until the next complete reboot.
WZ50 device not completing boot sequence after battery swap
The WZ50 runs a BMS learn cycle on first use with a new cell. If the device stalls mid-boot, the battery voltage is likely sitting below the BMS initialisation threshold — common after a new pack has been in storage. Connect the charger before powering on, let it reach at least 12.5V, then attempt boot. One full charge-discharge cycle completes the learn process and clears the fault.
Low battery alarm triggering immediately after a confirmed full charge
The WZ50 charge IC applies a conservative upper limit on an unfamiliar cell, so the first charge often terminates early — the indicator reads full but cell voltage is 11.8–12.0V rather than the 12.5V the BMS alarm threshold expects. This isn't a faulty pack. Run one complete charge-discharge-recharge cycle and the charge IC recalibrates to the actual cell capacity. After that cycle, the low battery alarm clears at its correct threshold.