About this replacement
Zondan Apollo N5 / ZD120D — 11.1V Li-ion Replacement Battery (LI13S020F)
This 11.1V 2600mAh lithium-ion battery replaces the OEM LI13S020F cell in the Zondan Apollo N5 and ZD120D medical devices. Both units run the same 11.1V three-cell architecture and use an identical connector and BMS handshake, so a single cell SKU covers both platforms. Capacity is rated at 2600mAh (28.86Wh), matching OEM specification.
- Apollo N5 and ZD120D platform fit: Both models share the same voltage rail, physical connector, and BMS communication protocol. The battery management system on each device authenticates cell chemistry at boot — this replacement passes that handshake without modification or firmware changes.
- Bench tested on actual hardware: We cycled this cell through charge, boot, and load sequences on compatible hardware. The BMS completed its initialisation routine, accepted the charge profile, and did not throw a fault code at any point during testing.
- Power-on self-test behaviour after installation: After fitting this cell, allow the Apollo N5 to complete its full power-on self-test without interruption. Medical devices run a BMS verification routine at startup — cutting power mid-sequence can trigger a persistent battery fault that survives until the next full reboot cycle.
Device not completing boot sequence on new battery
The Apollo N5 and ZD120D run a staged boot that includes a BMS query before the main OS loads. If the cell voltage is below approximately 10.5V — which is common after shipping — the device may halt at the hardware check screen rather than completing startup. This is a low-voltage lockout, not a faulty cell. Connect the charger first and bring the cell above 11.0V before attempting to power on.
Charge indicator not reaching 100% on the first charge cycle
On the first charge after installation, the device's charge IC applies a conservative current limit while it calibrates against the new cell's internal resistance. This often results in the indicator stalling between 90% and 98% before the session ends. It is not a capacity defect. Run one complete charge-discharge cycle and the calibration corrects — subsequent charges will terminate at full capacity.