Opticon H15 CMOS Backup Battery 3.7V 150mAh Li-Polymer

Opticon H15 Series — 3.7V Li-Polymer CMOS Backup Battery (D8296-26-02041)

This is a 3.7V, 150mAh Li-Polymer backup cell for the Opticon H15 mobile data terminal. It maintains the real-time clock and SRAM contents when main power is removed or the primary battery is swapped. Fits H15, H-15a, H-15b, H-15AJ, and five additional H15 variants sharing the same backup circuit.

• H15 family compatibility: All listed H15 variants use the same backup rail voltage and connector footprint. The CMOS cell feeds the RTC circuit and SRAM independently of the main Li-ion pack, so any model in this family that loses transaction data or resets its clock on power-down shares the same depleted-cell root cause.
• Bench tested on actual hardware: We measured open-circuit voltage before and after install, confirmed BMS handshake with the RTC circuit, and verified that system clock and configuration data persisted across a full main-battery disconnect cycle.
• Clock correction after install: After fitting this cell, navigate to the H15 date and time settings and enter the correct values before resuming operation. The CMOS cell powers the RTC circuit directly — any interruption resets the clock to a default value, and the terminal will not correct it automatically.

RTC clock resetting to a default date after every power cycle

The H15 RTC circuit requires a minimum retention voltage of 2.8V from the backup cell to hold the clock and SRAM contents. When the backup cell drops below that threshold, the RTC loses power the moment the main battery is disconnected, and the clock resets to a factory default on next boot. A cell that measures below 2.8V on a multimeter is below the retention floor regardless of how the terminal behaves under main power. Replace the cell, then manually set the correct date and time in the device settings.

New backup cell reading low voltage straight out of the packaging

Li-Polymer backup cells ship at a reduced storage voltage to slow capacity loss during warehousing — a fresh cell may read 3.4–3.5V rather than the nominal 3.7V. This is normal and does not indicate a faulty cell. Once installed and connected to the H15 backup circuit, voltage stabilises toward nominal within the first few charge cycles from the main battery. If the cell reads below 3.0V before install, do not use it — confirm with a multimeter across the cell terminals before fitting.