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Overview

Battery Conservation Mode helps prolong your laptop battery’s lifespan by limiting the maximum charge to 80%. This feature is especially useful if you primarily use your laptop while plugged in.
Keeping lithium-ion batteries at 100% charge for extended periods accelerates degradation. Limiting charge to 80% significantly extends overall battery health and lifespan.

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How It Works

When Battery Conservation Mode is enabled:
  • Your battery will only charge up to 80% capacity
  • Charging stops automatically at the 80% threshold
  • The battery will maintain this level while plugged in
  • Your system continues running on AC power after reaching 80%
If your battery is already above 80% when you enable this feature, it won’t discharge to 80%. The limit only applies to charging cycles.

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When to Use Battery Conservation

Desktop Replacement

Perfect if your laptop stays plugged in at a desk most of the time

Extended Laptop Lifespan

Plan to keep your laptop for several years and want to maintain battery health

Stationary Workstation

Use your laptop in a fixed location with constant power access

Battery Already Degraded

Already experiencing battery wear and want to prevent further degradation

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When to Disable

  • Before traveling or working away from power outlets
  • When you need maximum battery runtime for the day
  • Before long flights or commutes
  • When you need every percentage point of battery capacity

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How to Enable Battery Conservation

  1. Open KVantage
  2. Locate the Battery Threshold toggle switch
  3. Click the switch to enable Battery Conservation Mode
  4. Read the warning message that appears below the switch
  5. The setting takes effect immediately
The switch shows a visual indicator when enabled. Your current battery percentage doesn’t change immediately - the 80% limit applies to the next charging cycle.

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Important Warning Message

When you enable Battery Conservation Mode, KVantage displays this message:
“Please, consider that the threshold value cannot be customized in all Lenovo laptops. It’s a premium feature of some models.”
This means:
  • The 80% threshold is fixed and cannot be changed to other values (like 60% or 90%)
  • Custom threshold selection is not yet implemented in KVantage
  • Some older or budget Lenovo models may not support this feature at all

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Interaction with Rapid Charge

Battery Conservation Mode and Rapid Charge are mutually exclusive:
  • Enabling Rapid Charge automatically disables Battery Conservation
  • You cannot have both features active simultaneously
  • This is enforced by KVantage to prevent conflicting battery management strategies
When you toggle Rapid Charge on, Battery Conservation Mode will automatically turn off. This ensures your battery management settings don’t conflict.

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Technical Details

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Daemon Protocol

Battery Conservation Mode communicates with the daemon using these commands: Get Current Status: 
get conservation
Returns:
  • 0x1 - Conservation mode enabled (80% limit active)
  • 0x0 - Conservation mode disabled (normal 100% charging)
Set Conservation Mode: 
set conservation <value>
Where <value> is:
  • 1 - Enable conservation mode (80% limit)
  • 0 - Disable conservation mode (normal charging)

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ACPI Commands

Under the hood, the daemon writes to the ACPI call interface:
  • Enable: \_SB.PCI0.LPC0.EC0.VPC0.SBMC 0x03
  • Disable: \_SB.PCI0.LPC0.EC0.VPC0.SBMC 0x05

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Implementation Reference

The battery conservation UI is implemented in: 
composeApp/src/jvmMain/kotlin/com/korealm/kvantage/ui/mainUI/BatteryThreshold.kt:48-50
Key features:
  • Fetches current state on initialization with loading indicator
  • Automatically disabled when Rapid Charge is enabled
  • Shows animated warning message when activated
  • Persists setting across application restarts

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Future Feature: Custom Thresholds

The source code shows commented-out UI for custom threshold percentage selection. This feature is planned but not yet implemented: 
// Commented out as I currently have no time to do an implementation of this :(
// var percentage by remember { mutableIntStateOf(80) }
In the future, you may be able to set custom charge thresholds (e.g., 60%, 70%, 85%) depending on your needs and hardware support.

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Compatibility

Battery Conservation Mode requires:
  • A compatible Lenovo laptop with ACPI firmware support
  • The acpi_call kernel module loaded
  • Root/sudo privileges (handled automatically by KVantage)
Most Lenovo ThinkPad, IdeaPad, and Legion models support this feature. If your laptop doesn’t support it, the toggle will still appear but may not function correctly.

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Troubleshooting

Your laptop model may not support battery conservation via ACPI. Check your laptop’s specifications and BIOS version. Ensure the acpi_call kernel module is loaded.
The setting may not have applied correctly. Try toggling it off and on again. Some laptops require a full discharge-charge cycle for the threshold to take effect.
KVantage’s daemon requires root access to write to ACPI. Ensure pkexec is working correctly and you’re granting permission when prompted.
This feature is not yet implemented. Currently, only the fixed 80% threshold is supported. Check for updates to KVantage for future support.

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