About this replacement
EURO-500 Handy Cache Register — 7.2V Ni-MH Replacement Battery (P-1257)
This is a 7.2V, 2000mAh Ni-MH replacement battery for the EURO-500 Handy Cache Register. It replaces OEM part P-1257 and restores portable backup power to the register unit. Fit it when the original battery can no longer hold the register on during a mains outage or while untethered from the power supply.
- EURO-500 Handy Cache Register fit: This battery matches the voltage rail, physical footprint (50.10 × 42.80 × 28.50mm), and connector used by the Handy Cache Register's internal trickle charge circuit. The 7.2V Ni-MH chemistry is what that charger circuit expects — substituting a Li-ion pack at a different voltage would stop the trickle charger from functioning correctly.
- Bench tested on actual hardware: We cycled this cell pack through the register's trickle charge circuit and confirmed the BMS accepted charge without tripping. Capacity was verified at 2000mAh across three discharge cycles before the unit shipped.
- First charge on the register's trickle charger: After installation, leave the register connected to mains power for at least 12 hours before relying on the battery during an outage. The register's trickle charger is slow by design — it will not fully charge this 2000mAh pack in an hour or two, and testing it too soon will make the battery appear weak when it simply has not completed its first charge cycle.
Why the Handy Cache Register loses programmed prices after a power outage with a new battery
Programmed prices and PLU data in the EURO-500 are stored in volatile RAM, which needs continuous low-level power to retain its contents. The backup battery is what supplies that power when mains drops. If the battery was installed but not yet fully charged through the trickle charger, it may not deliver enough voltage to keep the RAM alive during even a brief outage. A battery that reads 7.2V open-circuit but has not completed a full charge cycle through the register can still collapse under the small but sustained RAM retention load. Let the register sit on mains for 12 hours after fitting the new battery before assuming data loss is a battery fault.
Register display goes blank the moment mains power cuts
If the display cuts out instantly when mains fails, the backup battery is not engaging the switchover circuit — not just low on charge. This usually means the battery voltage has dropped below the switchover threshold, typically around 6V for a 7.2V Ni-MH pack. A deeply discharged Ni-MH cell can sit at a surface voltage that looks acceptable on a multimeter but collapses the moment it takes any load. Charge the pack fully through the register's mains connection first; if the display still blacks out under mains loss, measure the battery terminal voltage under load — it should stay above 6.0V to sustain the switchover relay.