About this replacement
Welch-Allyn 460 Green Series Diagnostic Headlight — 3.6V Ni-MH Replacement Battery (72270)
This is a 3.6V, 500mAh Ni-MH rechargeable battery for the Welch-Allyn 460 Green Series Diagnostic Headlight. It fits the 4607X, Green Portable Headlight System, and LED Portable Diagnostic Headlights. Voltage and capacity match OEM part 72270 exactly.
- 460 Green Series platform fit: The 4607X and Green Portable Headlight System share the same battery bay, connector pinout, and 3.6V power rail. A single cell format services the entire platform without modification.
- Bench tested on actual hardware: We ran a full charge-discharge cycle on this cell in the 460 Green Series headlight. The BMS accepted the cell, completed its verification pass, and the charge indicator tracked normally through both stages of the charge cycle.
- First-use self-test protocol: After installing this battery, allow the headlight to complete its full power-on self-test without interrupting power. The BMS runs a chemistry verification at startup — cutting power mid-sequence logs a false battery fault that won't clear until a complete reboot and fresh self-test pass.
Low battery alarm on the 460 Green Series immediately after a confirmed full charge
The 460 Green Series BMS stores a learned capacity profile from the previous cell. When a new Ni-MH cell is installed, the BMS compares early discharge voltage against the stored OEM threshold — a fresh cell that hasn't completed a conditioning cycle reads below that threshold. The headlight triggers a low-battery alarm even though the cell is fully charged. Run one complete charge-discharge cycle through the device before clinical use. After that cycle, the BMS updates its reference profile and the alarm clears.
Headlight will not power on after the replacement battery sat in storage
Ni-MH cells self-discharge at roughly 1–3% per day at room temperature. A cell stored for several weeks can drop below the BMS recovery threshold — typically around 3.0V for a 3.6V Ni-MH pack — and the device refuses to power on. This is a protective lockout, not a cell fault. Place the battery in the charger and allow a full charge cycle to complete before reinserting. If the charger shows no activity after 10 minutes, the cell may need a trickle pre-charge before the main charge stage engages.