Why did my AlphaESS backup stop during a power cut?
Short answer
If backed-up circuits draw more than the inverter's backup rating (5 kW on SMILE-G3-S5 and B5, 3.68 kW on S3.6) the inverter shows Output_overload (100043) or Output_short (100042) and stops. Switch off heavy appliances on backed-up circuits; an overload may recover, but a short circuit needs the installer. Checked 24 September 2026.
Last checked 24 September 2026 · 1 source
What does this mean?
Backup switchover under 20 ms per datasheet 100043 overload: reduce loads, restart 100042 short: installer tests backup wiring
What should I do first?
Record the code and current battery state before changing settings. Follow only the owner-safe reset steps in the manual.
When do I need an engineer?
Use an installer or manufacturer support route if the fault returns, involves isolation or protection, or the manual does not give an owner reset.
What to do next
If the system is hot, smoking, damaged or making unusual electrical noises, move away from it and follow the manufacturer emergency guidance.
Sources
Last checked: 24 September 2026