Here's why:
* Preventing loss of memory: Modern cars store many settings in the computer systems, including radio presets, seat positions, and possibly even some engine control parameters. Without a backup power source, disconnecting the battery can cause these settings to be lost.
* Avoiding trouble codes: Disconnecting the battery can trigger trouble codes, potentially requiring a diagnostic scan to clear them. A backup power source minimizes this risk.
* Protecting sensitive electronics: Sudden power loss can potentially damage sensitive electronic components. While unlikely in most cases, a backup power source minimizes this risk.
* Easier work: Having a backup power source maintains power to things like the interior lights, allowing you to work more easily.
In summary, while you *can* technically replace the battery without a backup, using one makes the process significantly smoother, prevents potential problems, and saves you time and frustration. A simple battery maintainer connected to the car's lighter socket is sufficient for most battery replacements.
