About this replacement
Apple MacBook Pro 15" — 3V Lithium Replacement Battery (922-7913)
This is a 3V lithium CMOS backup battery for the Apple MacBook Pro 15", covering models A1211, A1260, and MA609LL among others. It holds 150mAh (0.45Wh) and keeps the RTC circuit powered when the MacBook is shut down or disconnected from mains. Without it, the machine loses its clock, date, and firmware settings every time main power is removed.
- A1211, A1260, and MA609LL compatibility: These models share the same motherboard footprint and connector for the CMOS cell, running the same RTC circuit at 3V. The 922-7913 part number covers all of them — same physical dimensions, same retention voltage requirement.
- Bench tested on actual hardware: We ran this cell on a MacBook Pro 15" board and confirmed the RTC held a stable 3.0V with no voltage sag after a cold-start. The SRAM retained all settings through repeated mains disconnections.
- Post-installation clock correction: After fitting this cell, open System Preferences and set the correct date and time manually, then allow macOS to sync via NTP. The RTC circuit defaults to a factory timestamp the moment the old cell is pulled — the new cell holds whatever the clock is set to next, so confirm the time is correct before closing the machine.
MacBook Pro 15" clock resetting to 2000 after every power cycle
When the CMOS cell drops below 2.8V, the RTC circuit loses retention voltage and the clock resets to a default factory date — typically January 1, 2000 — every time the main battery dies or mains power is cut. The MacBook may still boot normally when plugged in, which leads many users to blame software. The actual fault is the coin cell no longer holding enough charge to maintain SRAM state during power-off. Replace the 922-7913 cell, then set the correct date and time in System Preferences and verify it survives a full shutdown and cold restart.
CMOS checksum error on boot after fitting a new coin cell
A checksum error on first boot after a cell swap usually means the CMOS was completely depleted before replacement — the firmware detects that stored values no longer match the checksum written at last save. This is not a fault with the new cell. Enter the MacBook's firmware settings immediately after the error prompt, confirm or re-enter the date, time, and any custom settings, then save and exit. The checksum recalculates on save, and the error will not reappear provided the new cell is seated correctly and reading at or above 2.8V.