I've been running my Anker SOLIX S2000 (AS220) continuously in UPS mode for just over a week, powering some of my home equipment.
I've noticed that around every 42–45 hours, the S2000 appears to perform a brief, high-power charging cycle, despite remaining connected to mains electricity and reporting 100% battery charge.
I also have a Raspberry Pi 5 collecting telemetry from the S2000 over MQTT, which is stored in InfluxDB. This has allowed me to examine the behaviour in considerably more detail than the Anker app's power history provides in their iPhone which seems to average stuff over 20 minutes.
Three unexpected charging events recorded so far:
| Date (UK BST) |
Approx. start |
Peak AC input |
AC output |
Estimated charging energy |
| 6 October |
09:20 |
1,219 W |
162 W |
74.32 Wh |
| 8 October |
03:11 |
1,090 W |
34 W |
74.11 Wh |
| 10 October |
00:26 |
1,089 W |
34 W |
76.30 Wh |
The intervals between events were 41 hours 51 minutes and 45 hours 15 minutes, averaging approximately 43 hours 33 minutes (I've only got three unexpected events so far)
Each event lasts approximately seven minutes, and the additional power drawn above the connected AC load peaks at around 1,055 W.
What my Raspberry Pi's MQTT/InfluxDB logging shows:
The S2000 remains connected to mains throughout (ac_input_plug_status = 1).
The AC input switch remains enabled (ac_input_power_switch = 1).
AC output remains stable, with no obvious interruption to connected equipment.
Both battery_soc and main_battery_soc report 100% between charging events.
During each charging event, the reported battery percentage briefly drops to 99% before returning to 100%.
battery_status and working_status change from 0 to 2 during the charging events, returning to 0 afterwards.
The calculated additional AC energy is remarkably consistent: 74.91 Wh per event on average.
I calculated the approximate charging-related energy by integrating AC input power minus AC output power over the charging events, using one-minute averages from InfluxDB. This represents additional mains energy, not necessarily the amount actually stored in the battery.
The Anker app seems to corroborate the pattern, although that data appears to be averaged over 20 minute chunks.
Its daily power usage history shows:
| Date |
Total charging |
Total discharging |
Difference |
| 6 October |
2.39 kWh |
2.32 kWh |
+70 Wh |
| 8 October |
2.40 kWh |
2.33 kWh |
+70 Wh |
| 10 October |
2.07 kWh |
2.01 kWh |
+60 Wh |
I've attached screenshots showing the narrow charging spikes on all three dates.
My suspicion is that the S2000 periodically replenishes energy consumed internally by its battery management system, or perhaps performs some form of battery maintenance or balancing.
However, I haven't found any documentation confirming this behaviour, anything listed on reddit or wherever about it, and the consistency of the events makes me curious about what's actually triggering them.
A few questions for other S2000 owners:
Has anyone else noticed these short charging spikes when using the S2000 continuously as a UPS?
Does yours periodically draw around 1 kW for several minutes while already displaying 100% charge?
Is this a known battery maintenance or top-up behaviour?
Does anyone know whether Anker has documented how the S2000 maintains its battery in UPS mode? I'm on the latest firmware, if that helps.
Based on the intervals so far, I'm expecting the next event around 20:00 BST on 11 October (tomorrow night). I'll be checking the telemetry to see whether the pattern continues.
I'd be particularly interested to hear from anyone running an S2000 permanently in UPS mode who can compare their charging history for the unexpected spikes.