5051dfdc8c
- modules/t490.nix: TLP power management, CPU throttling (throttled), S3 sleep, remote Nix builders (cluster), fwupd, fprintd, fprintd, Syncthing, Tailscale, Intel VA-API, TrackPoint sensitivity, PipeWire defaults - flake.nix: add nixos-hardware input, import T490 module + nixos-hardware - docs/T490-HARDWARE.md: WiFi variants, graphics, audio, fingerprint, sleep guide - docs/T490-BATTERY.md: TLP config, threshold strategy, real-world battery numbers - docs/T490-OFFLOADING.md: local vs cluster split, remote builder setup - MIGRATION.md: add T490 post-install steps (fwupd, fprint, remote build key) - README.md: reflect new module and docs structure
56 lines
1.8 KiB
Markdown
56 lines
1.8 KiB
Markdown
# T490 Battery Life
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## Hardware Baseline
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- **50 Wh** internal battery (3-cell)
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- Panel draws ~4-5W at typical brightness
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- CPU TDP-up 25W, TDP-down 10W
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## Real-World Estimates
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| Scenario | Runtime |
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|---|---|
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| Idle, screen off | 10-12 hours |
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| Light work (terminal, notes) | 7-8 hours |
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| Dev work (editor, browser, kubectl) | 5-6 hours |
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| Browsing (10+ tabs, video) | 4-5 hours |
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| Compiling / heavy CPU | 1.5-2 hours |
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## TLP Configuration
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`modules/t490.nix` configures:
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- `powersave` governor on battery, `performance` on AC
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- Turbo disabled on battery
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- CPU capped at 40% max frequency on battery (~1.7 GHz)
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- WiFi power saving on battery
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- PCIe runtime PM (auto on battery)
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- Intel GPU frequency limits (300-600 MHz on battery)
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### Battery Health Thresholds
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Lenovo Battery Team recommendations — configured in `modules/t490.nix`:
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- **Start charging** below 40%
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- **Stop charging** at 80%
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- Thresholds persist in firmware (survive reboots without TLP)
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This dramatically extends battery lifespan. Don't leave plugged in at 100% for days.
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## CPU Throttling Fix
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Intel Whiskey Lake CPUs have a bug where BD PROCHOT fires spuriously, locking the CPU at 400 MHz. The nixos-hardware T490 module enables `services.throttled` (erpalma/throttled) — this is mandatory.
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**Skip thermald** — it conflicts with throttled. `services.thermald.enable = false` is set in `modules/t490.nix`.
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## Additional Tweaks
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- `pcie_aspm=force` — force PCIe power saving
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- `i915.enable_rc6=7` — max GPU power saving
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- `noatime,nodiratime` — reduce disk writes
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- **zram swap** at 50% of RAM — faster, saves NVMe writes
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## Quick Wins (No Config Needed)
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- Lower screen brightness (40-60% is plenty — biggest power draw)
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- Disable Bluetooth when not in use
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- Use S3 deep sleep (not s2idle)
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- Close unused browser tabs
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