The AMD-powered ThinkPad A485 uses Lenovo’s Power Bridge design: a small internal battery plus a removable external pack. This guide streamlines your path from diagnosis to checkout and installation, tailored specifically for A485 types 20MU/20MV.
1) Quick Diagnosis: Is It the Internal, External—or Both?
- Generate a Windows battery report: open PowerShell as Admin →
powercfg /batteryreport→ open the HTML file and compare Full Charge Capacity vs Design Capacity for Battery 1 (internal) and Battery 2 (external). - Use Lenovo Vantage / UEFI diagnostics: check health % and cycle count per battery.
- Isolation test: remove the rear battery and run briefly off the internal on AC unplug. Instant shutdown = internal is failing. Re-attach a known-good external to evaluate the external side.
Symptoms that mean “replace soon”: rapid drop at 20–40%, “Battery needs replacement” warnings, “plugged in, not charging,” or any swelling / lifted palm-rest. Stop using a swollen pack immediately.
2) Choose the Right Battery for Your A485
Internal (always 24Wh)
01AV421 — 24Wh
For failed Battery 1, hot-swap reliability, and accurate charge readings.
External (thin travel)
01AV423 — 24Wh
Keeps the profile slim; good for desk + short trips.
External (maximum runtime)
01AV425 — 48Wh
Best for travel days and meetings: roughly doubles the external capacity.
Rule of thumb: if your A485 still runs but endurance is short, upgrading the external to 48Wh gives the biggest instant boost. If hot-swap fails or the machine dies as soon as you remove the external, the internal also needs replacement.
3) Specifications & Comparison
4) Install in Minutes
External (01AV423 / 01AV425)
- Shut down or keep on AC.
- Slide the rear latch, remove the old pack.
- Insert the new pack until it clicks, lock the latch, power on and verify in Windows/Vantage.
Internal (01AV421)
- Power down, unplug, hold power 15s to discharge.
- Remove bottom cover (Phillips) and release clips gently.
- Disconnect battery cable first, remove screws, lift out.
- Fit new pack, route cable cleanly, reconnect firmly, reassemble.
Safety: If a pack is swollen, do not compress or puncture it. Isolate in a fire-safe area and recycle via local e-waste programs.
5) Calibration & Care (for accurate readings and long life)
- Calibrate once after install: charge to 100% → rest 1–2 hours → discharge to 5–10% → charge back to 100% uninterrupted.
- Vantage updates: keep BIOS and power-related drivers current.
- Storage: if unused for weeks, store around 40–60% in a cool, dry place; avoid leaving packs fully depleted.
FAQ
Can I hot-swap on the A485?
Yes. Power Bridge drains the external first so you can swap it while the internal keeps the machine alive briefly. If hot-swap fails, the internal is likely weak.
Will the 48Wh external make the laptop heavier?
It adds weight and a slightly taller rear foot, but the runtime gain is substantial—ideal for travel and meeting-heavy days.
“Plugged in, not charging” — battery or software?
Often it’s battery wear or thresholds in Vantage. Disable conservation mode, reboot, and re-check. If health/capacity are low, replace the affected pack.