Righton Retinomax 2 Replacement Battery 6V 2100mAh

Righton Retinomax 2 / Retinomax II — 6V Ni-MH Replacement Battery

This 6V 2100mAh Ni-MH pack replaces the internal battery in the Righton Retinomax 2 and Retinomax II portable autorefractors. These handheld devices are used for objective refraction measurement in optometry and ophthalmology settings. Capacity is 2100mAh (12.6Wh) — taken from product data, not estimated.

• Retinomax 2 and Retinomax II compatibility: Both models use the same battery bay geometry, connector orientation, and 6V cell configuration. The BMS in each unit expects the same charge termination behaviour — delta-V cutoff — which Ni-MH cells deliver natively. No connector modification needed.
• Bench tested on actual hardware: We cycled this pack through the Retinomax charge circuit and confirmed the onboard charger reached full termination without fault codes. The BMS accepted the pack without a handshake error on first insertion.
• Post-install calibration cycle: After fitting this pack, run a full calibration cycle through the instrument menu before using it on patients. The Retinomax maps battery state during calibration — skipping this step causes premature low-battery warnings to fire during the first measurement session, even with a full charge.

BMS lockout after the Retinomax sat unused in a carry case for months

Ni-MH cells self-discharge over time. If the Retinomax was stored with the original pack installed, that pack may have discharged below the BMS recovery threshold — typically around 4.5V for a 6V Ni-MH pack. A replacement pack avoids this entirely because it ships with enough residual charge to wake the charge circuit. Insert the new pack, connect the charger immediately, and let the instrument complete a full charge cycle before powering on.

Retinomax shuts down mid-measurement with no low-battery warning

This happens when the measurement routine triggers the illumination and motor systems simultaneously, pulling a short current spike the aged cell can no longer sustain. Voltage sags briefly below the BMS cutoff threshold and the unit shuts off — not because capacity is gone, but because internal cell resistance has risen enough that peak demand can't be met. A fresh pack with lower internal resistance handles the spike without voltage drooping past cutoff. After fitting the new pack, verify resting voltage reads at or above 6.0V before your first patient session.