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Overview

Rapid Charge mode enables faster battery charging by increasing the charging current. This feature is useful when you need to quickly top up your battery before heading out, but it comes with trade-offs for battery longevity.
Rapid charging generates more heat and can accelerate battery degradation over time. Use this feature sparingly and only when you need a quick charge.

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How It Works

When Rapid Charge is enabled:
  • Your laptop’s charging circuitry increases the charging current
  • The battery charges significantly faster than normal
  • More heat is generated during the charging process
  • The charging cycle may be less gentle on battery chemistry
Rapid Charge is most effective when your battery is below 80%. Charging naturally slows down above 80% to protect battery health regardless of this setting.

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The Trade-Off: Speed vs. Longevity

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Benefits

Faster Charging

Get more charge in less time when you’re in a hurry

Convenient for Travel

Quickly charge during short breaks or layovers

Emergency Power

Essential when you urgently need battery power

Quick Top-Ups

Maximize charging during brief periods near an outlet

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Drawbacks

  • Increased Heat: More heat generation during charging, which accelerates battery wear
  • Battery Degradation: Higher current stresses battery chemistry, reducing lifespan over time
  • Incompatible with Conservation: Automatically disables Battery Conservation Mode
  • Diminishing Returns: Less effective above 80% charge
For optimal battery health, use standard charging most of the time and reserve Rapid Charge for situations when you genuinely need it.

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When to Use Rapid Charge

  • Before travel: Quick charge before leaving for a flight or meeting
  • Short breaks: Maximize charging during a 30-minute coffee break
  • Emergency situations: When you urgently need battery power
  • Occasional use: Not planning to keep the laptop for many years

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When to Avoid

  • Overnight charging: No rush, standard charging is healthier
  • Long-term battery health: If you want to maximize battery lifespan
  • Already using conservation mode: They conflict with each other
  • Hot environments: Rapid charging generates additional heat

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How to Enable Rapid Charge

  1. Open KVantage from your application menu
  2. Locate the Rapid Charge toggle switch
  3. Click the switch to enable Rapid Charge mode
  4. The charging rate increases immediately if your laptop is plugged in
  5. The switch displays with a secondary color (different from other toggles)
The Rapid Charge toggle has a distinctive secondary color (orange/amber) to differentiate it from other features and indicate its special nature.

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Interaction with Battery Conservation Mode

Rapid Charge and Battery Conservation Mode have an important relationship:
  1. Enabling Rapid Charge automatically disables Battery Conservation Mode
  2. Battery Conservation Mode stays disabled while Rapid Charge is active
  3. The two features are mutually exclusive by design
Why? Rapid Charge aims to charge as quickly as possible, while Battery Conservation limits charging to protect battery health. These goals are fundamentally opposed, so KVantage prevents you from enabling both simultaneously.
If you have Battery Conservation Mode enabled and turn on Rapid Charge, your battery will charge beyond 80% up to 100%. Remember to re-enable conservation mode after disabling rapid charge if you want to return to the 80% limit.

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Technical Details

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Daemon Protocol

Rapid Charge communicates with the KVantage daemon using these commands: Get Current Status: 
get rapid
Returns:
  • 0x1 - Rapid Charge enabled
  • 0x0 - Rapid Charge disabled (normal charging speed)
Set Rapid Charge: 
set rapid <value>
Where <value> is:
  • 1 - Enable Rapid Charge
  • 0 - Disable Rapid Charge

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ACPI Commands

The daemon writes to the laptop’s ACPI interface:
  • Enable: \_SB.PCI0.LPC0.EC0.VPC0.SBMC 0x07
  • Disable: \_SB.PCI0.LPC0.EC0.VPC0.SBMC 0x08

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Implementation Reference

The Rapid Charge UI is implemented in: 
composeApp/src/jvmMain/kotlin/com/korealm/kvantage/ui/mainUI/RapidCharge.kt
Key implementation details:
  • Uses secondary theme colors (orange/amber) for visual distinction
  • Automatically signals to disable Battery Conservation when enabled
  • Fetches current state on initialization
  • Shows disabled state with loading indicator until initialization completes
  • Persists setting across application restarts

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Battery Health Best Practices

To maximize your battery’s lifespan while occasionally using Rapid Charge:
1

Use standard charging by default

Keep Rapid Charge disabled for routine charging sessions
2

Enable Battery Conservation for daily use

If your laptop is often plugged in, use the 80% charge limit
3

Reserve Rapid Charge for emergencies

Only enable when you genuinely need a quick charge
4

Disable after use

Turn off Rapid Charge once you’ve reached your target charge level
5

Monitor battery temperature

If your laptop gets very hot while charging, consider disabling Rapid Charge

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Compatibility

Rapid Charge requires:
  • A Lenovo laptop with hardware support for rapid charging
  • The acpi_call kernel module loaded
  • Root/sudo privileges (handled automatically by KVantage)
  • Compatible BIOS/firmware version
Most modern Lenovo laptops support Rapid Charge, but some older or budget models may not. The toggle will appear regardless, but may not function on unsupported hardware.

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Troubleshooting

Your laptop model may not support rapid charging via ACPI, or the difference may be subtle on your specific model. Some laptops have limited rapid charge implementations.
Check that the acpi_call kernel module is loaded (lsmod | grep acpi_call). Ensure you granted root permission when prompted by pkexec.
This is expected behavior with Rapid Charge. If temperatures seem excessive, disable the feature and allow standard charging. Consider improving ventilation around your laptop.
This is intentional behavior. Rapid Charge and Battery Conservation Mode are mutually exclusive. Re-enable conservation mode after disabling rapid charge if desired.
Most laptops naturally slow charging above 80% to protect the battery, regardless of the Rapid Charge setting. This is normal battery management behavior.

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