Causes
- Unstable or wrong-band Wi-Fi during the download — the F3800 Plus's Wi-Fi radio only supports 2.4GHz networks, and Anker's own guide says the unit must be within 10m (33ft) of the router with few obstacles. If your phone is on the 5GHz band while the unit is on 2.4GHz (or the signal is weak), the firmware download can stall or drop mid-transfer and the update fails or gets stuck at a percentage.
- The unit timed out or powered down mid-update — the F3800 Plus has automatic shutdown/sleep behavior (MCU sleep after 12 hours idle, output-port auto-shutdown, and a hard power-off at 1% battery). If the unit's timeout settings kick in during the update, or the main switch gets turned off, the update aborts and can leave the firmware in a stuck state. Anker notes updates take under 10 minutes, so the unit must stay awake and powered the whole time.
- A buggy update release — in December 2025, firmware v3.5.6 for the F3800 Plus caused real problems: owners on r/SOLIX reported the update failed repeatedly and even "completely locked up my internet connection after 3 tries," forcing a modem and router restart. Community advice at the time was to hold off on that specific build. Server-side or release-specific issues can make a healthy unit fail an update.
- Corrupted app cache or a stale device link — the Anker app can hold onto a broken pairing after a failed update or a phone OS update. A region mismatch (the app region must match your registered account region) also blocks firmware delivery entirely, per Anker's Wi-Fi troubleshooting guide.
- A stuck firmware/hardware initialization fault — in a widely reported out-of-the-box case, a new F3800 Plus would not charge or discharge via AC and every firmware update failed "even after performing a pin reset," with the display only showing charge level and Wi-Fi status. That combination points to a firmware state the update process itself can't recover from — not a network problem.
How to Fix
- Move the unit close to the router and use 2.4GHz Wi-Fi — place the F3800 Plus within 10m (33ft) of your router with minimal walls between them, and confirm your phone is connected to the 2.4GHz SSID (many routers name it separately, e.g. "Home" vs "Home_5G"). Check that the app's region setting matches the region your Anker account is registered in. Then retry the update from the app: Settings → Device Info → check firmware version → follow the on-screen prompts.
- Power-cycle the unit and the router before retrying — turn the F3800 Plus fully off and back on, and restart your modem/router. This clears the network lock-up symptom owners saw with v3.5.6, where the failed update wedged the home connection. Retry the update once the network is stable.
- Keep the unit awake and powered during the update — make sure the battery is above 20% (a low battery can trigger auto-shutdown mid-install), keep the app open in the foreground, and disable aggressive battery optimization for the Anker app on your phone so it isn't killed mid-update. Don't touch the main power switch or unplug the unit until the update completes — Anker says it takes less than 10 minutes.
- Clear the app cache and re-link the device — fully close the Anker app, clear its cache (on Android: Settings → Apps → Anker → Storage → Clear Cache), and sign back in. If the app still shows a stale version, remove the F3800 Plus from the app, then re-add it by scanning/entering the serial number.
- Unpair the unit via the IoT button and re-pair — press and hold the IoT button on the F3800 Plus for more than 7 seconds to unpair it from the app, remove the unit from the app's device list, then press the IoT button once more and search for the device again. Reconnect and retry the update. This is Anker's official fix for app/device connection problems.
- Factory reset the unit — if the update is still stuck, insert a paper clip or pin into the reset hole for 1 second to factory reset the F3800 Plus. Then reconfigure Wi-Fi in the app and retry the firmware update from scratch. A factory reset clears the stuck firmware state that blocks the updater.
- Check for known-bad releases before updating — if a specific version is causing widespread failures (like v3.5.6 in December 2025), search for recent owner reports on r/SOLIX or r/anker first. Anker usually pulls or hotfixes a bad release within days; waiting for the next build is a legitimate fix. You can also contact Anker SOLIX support for the current recommended firmware version for your unit.
- Contact Anker SOLIX support with logs — if the update still fails after a stable 2.4GHz connection, a fresh pairing, and a factory reset — especially if AC charging/discharging is also dead — upload device logs via the app (Profile → Settings → Upload Log; the unit must be on Wi-Fi), and share your order number, the serial number (SN) on the back, and a short video of the failure. Owners with the stuck-initialization fault were sent replacement units under Anker's 5-year warranty.