About this replacement
Kowa SL14 Retinoscope — 7.2V Ni-MH Replacement Battery (120 070.00)
This is a 7.2V 2150mAh Ni-MH replacement battery for the Kowa SL14 retinoscope. The SL14 is a handheld ophthalmic instrument used in clinical settings to assess refractive error and examine the retina. This cell restores cordless operation when the original battery degrades or fails to hold charge.
- SL14 platform fit: The SL14 uses a 7.2V Ni-MH cell with a specific connector and BMS handshake tied to Kowa's part number 120 070.00. The voltage rail and physical dimensions — 87.40 × 31.80 × 31.50mm — must match exactly for the device to power on and complete its diagnostic cycle.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the SL14 platform and confirmed the BMS handshake, charge acceptance, and cutoff voltage all behaved correctly. The cell passed the device's internal verification on the first completed cycle.
- First-use startup protocol: After installation, let the SL14 complete its power-on self-test without interruption. The device runs a BMS verification sequence at startup — cutting power during this window causes a false battery fault that persists until the next full reboot.
SL14 boot sequence failing to complete after battery swap
The SL14 runs a hardware self-test at startup that includes a battery status check. A new Ni-MH cell that hasn't completed its first full charge-discharge cycle may not yet meet the BMS threshold the device checks against. This causes the boot sequence to stall or produce a battery fault code even when the cell is fully charged. Run one complete charge-discharge cycle before using the device clinically — this allows the BMS to establish accurate capacity baseline data.
Charge indicator stalling below 100% on the first charge
On the first charge, the SL14's charge IC applies a conservative current limit to an unrecognised cell, which can cause the indicator to plateau at 80–90% and stop advancing. This is not a faulty battery — it reflects the charge controller's cautious approach to a new cell with no usage history. Disconnect, allow the device to sit for 10 minutes, then recharge from that point. After one full cycle, the charge controller recalibrates and subsequent charges complete normally.