eufy Error S1 — Battery error
DIRECT ANSWER
COMMON CAUSES · RANKED
Dirty or oxidized charging pins MOST COMMON
Dust and oxide on the pins under the robot and on the base corrupt the charge reading the battery reports. eufy's own fix list starts here.
Adapter or base connection loose
eufy's procedure has you unplug and replug the adapter, try a different wall outlet and confirm the base indicator lights before blaming the pack.
Battery pack worn out or failing
eufy's battery guide lists "Error S1 during cleaning" as a sign the pack is done. Packs last roughly 300 to 500 charge cycles.
Battery connector loose after a swap UNCOMMON
On a recently opened robot, a half-seated battery connector reports as a battery error on the next start.
Battery outside its 0–40 °C window UNCOMMON
eufy's S1 article rates the lithium-ion pack for 0–40 °C (32–104 °F). A robot stored in a cold garage, or left in the sun, can report S1 until it comes back to room temperature.
HOW TO FIX IT
Power off the robot before opening the battery compartment, handle the pack by its tab, and never use a battery that is swollen, hot or leaking.
Power off the RoboVac
Switch the robot off at its power switch before you touch the base or the battery. eufy's S1 procedure starts with the switch, before anything at the dock.
Reseat the power chain
Unplug the adapter at both ends, reconnect it to the charging base, then plug it into a different wall outlet and confirm the base's indicator lights up.
Clean the charging pins
With the base unplugged, wipe the pins on the base and on the robot's underside with a dry, clean cloth until the metal is bright.
Re-dock within 6 feet
Place the robot facing the base within 6 feet, press the Home button and let it dock on its own so the pins meet properly. Then give it a full charge before the next mission.
Power on and run a test clean
Switch the robot back on and start a normal clean. eufy's pass mark is a full cycle without S1. If it completes, the fault was somewhere in the charging chain rather than in the pack.
Replace the battery if S1 returns
Power off, open the battery compartment and fit eufy's pack for your series: T2908061 for Bounce and G, T2937111 for X8. L70 Hybrid owners order theirs through support. Recycle the old one.
IF IT STILL FAILS
WHEN TO STOP
Stop, and do not charge it, if the pack is swollen, hot or leaking. Recycle it. If the robot is still under warranty (eufy's limited warranty counts from the purchase date), talk to support before you open the battery compartment: +1 (800) 994-3056 or [email protected]. They will ask for the receipt, the serial number and a short video of the error. And if a genuine new pack still throws S1, that is a job for support rather than a screwdriver.
COMPATIBLE PARTS
As an Amazon Associate, RoboFaults earns from qualifying purchases. Prices are shown on the retailer's site.
Lithium-ion battery T2908061 — Bounce & G series RoboVacs
eufy's official pack for Bounce and G series robots (300-500 charge cycles expected). Switch the robot off before opening the screwed battery door, buy genuine or known-brand cells only, and recycle the old pack.
Compatibility and replacement details → Check price on Amazon ↗
Lithium-ion battery T2937111 — X8 series
eufy's official X-series pack — the fix for an Error S1 that keeps returning during cleaning. Power off before opening the battery compartment and never use a swollen or hot pack.
Compatibility and replacement details → Check price on Amazon ↗MODELS AFFECTED
| Model | Status | Firmware | Parts | Verified |
|---|---|---|---|---|
| eufy RoboVac G30 / G30 Edge / G30 Hybrid Takes the T2908061 pack shared with the Bounce series. Both the G-series table and eufy's dedicated S1 article apply to it. · Source | active | — | Parts → | 2026-07-06 · Source |
| eufy Clean G40 / G40+ / G40 Hybrid+ | active | — | Parts → | 2026-07-06 · Source |
| eufy RoboVac L70 Hybrid (T2190) eufy does not sell its replacement battery self-serve; the battery guide says to contact support to order one. · Source | limited | — | — | 2026-07-06 · Source |
| eufy RoboVac X8 / X8 Hybrid Takes the T2937111 pack. The G-series T2908061 does not fit it. · Source | active | — | Parts → | 2026-07-06 · Source |
Models resolved from the series chips above. Support status comes from our EOL library; rows link to the matching parts and firmware pages.
FIELD NOTES
All three of eufy's official write-ups treat S1 as a charging problem before a battery problem. Adapter, base, pins, docking distance. Only the battery guide brings up the pack itself, and it does so as the last step. None of them cover the case an X8 Hybrid owner posted on a repair forum: S1 with a freshly charged pack and no base connected at all, seven or eight months into ownership. That pattern points at the robot's charging circuit or the pack's protection board, since the dock was out of the picture.
The second thing the official steps skip is what to do after a battery swap. They never mention restarting the robot. eufy's separate reset guide does, though: hold the power button for 10 to 20 seconds. Do that, and check the connector is pushed fully home, before deciding a new pack is faulty.
One generation note. Bounce models (11S, 15C, 30C) have no display, so they never say "S1". The same battery fault comes out as five beeps with a red LED. eufy's battery guide lists both, "4 or 5 beeps" for Bounce and "Error S1" for the G, L and X series, as reasons to replace the pack.
FAQ · REAL QUESTIONS
What does error S1 on a eufy RoboVac mean?
S1 is eufy's battery error, which means the robot can't get a healthy charge reading from its pack. eufy's articles treat it as a charging-chain fault first (adapter, base, pins) and a worn battery second. If S1 shows up mid-clean, that is the replacement sign.
How do I fix "Error S1 battery error" on a eufy?
Power off, reconnect the adapter at both ends on a different outlet, and wipe the pins on the base and under the robot with a dry cloth. Then park it facing the base within 6 feet and press Home. If S1 comes back after a full charge, replace the pack.
How do I reset a eufy RoboVac after error S1?
Take it off the dock and hold the power (or Clean) button for 10 to 20 seconds until it restarts. That is eufy's soft reset. A factory reset only clears Wi-Fi, maps and schedules, so it won't revive a worn battery.
How long should a eufy RoboVac battery last?
eufy rates its lithium-ion packs for roughly 300 to 500 charge cycles. With daily runs, performance can start dropping after about a year. eufy's listed replacement signs are a short runtime, a solid red charging light, and S1 during a clean.
Why does my eufy still say battery error with a new battery?
Usually the connector isn't fully seated, or the robot hasn't been restarted since the swap. Reseat the plug, hold the power button for 10 to 20 seconds off the dock, then run a clean. If a genuine eufy pack still shows S1, contact support.
Is error S1 the same as five beeps on a eufy 11S?
It is the same fault shown two ways. Bounce models (11S, 15C, 30C) have no screen, so a battery fault comes out as five beeps with a red LED. The G, L and X series show "Error S1" in the app. eufy's battery guide lists both as replacement signs.
Sources
- eufy Support — X8/LR20/LR30/L35 series voice alerts and solutions
- eufy Support — What if my RoboVac stops with Error S1? (L70 / G series)
- eufy Support — When should I replace the battery on my eufy RoboVac?
- eufy Support — G series voice alerts and quick solutions
- eufy — How to reset a robot vacuum (soft vs factory reset)
- eufy Support — How your eufy warranty service works
- Badcaps forum — eufy RoboVac X8 Hybrid error S1 (owner repair thread, Dec 2023)
Verification
Last verified: 2026-09-02 · How we verify a fault code
Corrections
Spotted an error? Report a correction — fixes ship within 48h and are logged on this page.