Real-Time Clock Resets if the Main Battery is Drained on Dell Laptops with no CMOS Battery
Summary: The following article provides information about what happens when the main battery is drained on Latitude xx2x and xx3x or Dell Pro 13 Premium laptops. Latitude xx2x and xx3x or Dell Pro 13 Premium laptops without a CMOS battery reset the Real-Time Clock (RTC) when the main battery is fully drained. ...
Symptoms
RTC resets after discharging the main laptop battery
Dell has removed the CMOS coin-cell battery from various newer models. Starting with the designs for the Latitude xx2x and xx3x generation of laptop. (For example: Latitude 5320, 7320, 7420, 7520, 9520, 9330, 9430, and Dell Pro 13 Premium PA13250 laptops.) This means that the RTC is reset when the main battery drains empty, and the AC adapter is not connected. You can check your laptops specifications to see if this is applicable to your laptop.
The laptop does not boot when the AC adapter is first connected if there is a battery drain. It goes through an RTC reset instead.
The laptop restarts several times during the reset process. The keyboards backlight or any other LED indicators may activate when the power button is held and after it is released. (This depends on how you configure your laptop.) Once the reset is complete, the laptop reboots into the Dell splash screen. This indicates that the reset was completed successfully.
- BIOS Defaults
- Last Known Good
- Custom User Settings
- Factory Defaults
The models that this RTC reset affects do not directly reset the most important BIOS settings. This reduces the inconvenience if it happens.
The following table shows how an RTC reset affects the BIOS settings:
| BIOS Setup Menu Category | RTC Reset | Details and Sub-Settings that are Affected |
|---|---|---|
| Boot Configuration | No Change | |
| Storage | No Change | |
| Security | No Change | |
| Passwords | No Change | |
| Update, Recovery | No Change | |
| System Management | No Change | |
| Virtualization Support | No Change | |
| Performance | No Change | |
| System Logs | No Change | |
| Integrated Device | Reset | Date & time; Camera; Audio; USB and Thunderbolt (TBT) Configuration; Enable Thunderbolt Technology Support; Enable Thunderbolt Boot Support; Enable Thunderbolt (and Peripheral Component Interconnect Express (PCIe) behind TBT) pre-boot modules; Disable USB4 PCIe Tunneling; Video and Power only on Type-C Ports; Type-C Dock Override; Disable USB4 PCIe Tunneling; Video and Power only on Type-C Ports; Type-C Dock Override; Lan; Miscellaneous Devices |
| Display | Reset | Display Brightness; Touchscreen |
| Connection | Reset | Wireless Device Enable; Enable United Extensible Firmware Interface (UEFI) Network Stack; Wireless Radio Control; Wireless Radio Control; HTTPs Boot Feature |
| Power | Reset | Battery Configuration; Advanced Configuration; Power; Peak Shift; USB PowerShare; Thermal Management; USB Wake Support; Block Sleep; Lid Switch; Intel Speed Shift Technology |
| Keyboard | Reset | Fn Lock Options; Lock Mode; Keyboard Illumination; Keyboard Backlight Timeout on AC; Keyboard Backlight Time out on Battery; Device Configuration Hotkey Access |
| Pre-boot Behavior | Reset | Adapter Warnings; USB-C Warnings; Fastboot; Extend BIOS POST Time; MAC Address Pass-Through; Sign of Life; Mouse and Touchpad |
Cause
The laptop models in this article do not possess a CMOS battery by design. This can lead to an RTC reset when you fully drain the main and only battery in the laptop.
Resolution
This is the expected behavior for these non-coin-cell models of laptop when you drain the main battery. The laptop is working as designed and expected under these circumstances.