Question: Is it normal to experience flickering of all lights in the house during the interval that the inverter switches between battery and grid source output modes? The flickering occurs even under low total load.

Additional info: I have a combination of incandescent bulbs and LED lights in the house.

There is a single geyser and stove that runs directly from the grid on separate circuits, not via the inverter

I include pictures and some setting and specs from the software, hopefully it is of some help.

System consist of 1x battery, 6x solar panels connected to a single inverter

RCT-AXPERT 5K Inverter

PYLONTECH US2000 48V 2,4KWh Lithium-Ion battery

Software settings and specs:
Driver: Axpert
Monitoring connection: Direct cable
Machine type: Off Grid
Topology: Transformerless
Max parallel units: 9 units
Nominal battery voltage: 48.0 V
Expected AC input voltage: 230.0 V
Max AC input current: 21.7 A
Max AC output apparent power: 5000 VA
Max AC output current: 21.7 A
Max AC output power: 4000 W

Battery settings
Battery type: User
Charger source priority: Solar first
Shutdown battery voltage: 46.8 V
To grid battery voltage: 47.0 V
Back to battery voltage: 49.0 V
Battery float charge voltage: 53.2 V
Battery bulk charge voltage: 53.2 V
Max charge current: 60 A
Max AC charge current: 10 A

Input/Output settings
Output mode: Single machine output
AC Input voltage range: Appliance
AC output frequency: 50.0 Hz
AC output voltage: 230.0 V
Output source priority: Solar/Battery/Utility
Overload bypass: Enabled
Overload restart: Enabled
Primary source interrupt alarm: Disabled

[![Inverter/battery setup][1]][1]

enter image description here

2 Answers 2


There are 2 types of systems open transition and closed transition systems. A open transition it is absolutely normal for a flicker because the transfer is open the power is cut as it is transferred to the other source.

The more expensive system is closed transition the system syncs and the transfer is made then the switch is opened from the utility. There are active systems out there for residential but as I mention these are more expensive. Closed transition transfers have no flicker.

I doubt very many internet only electricians have experience with closed transition as they much more expensive and normally on much larger (mansion size) residential and large commercial facilities like hospitals that need seamless power where they think there might be an issue they start the generator(s) and transfer without a flicker.

  • Thanks. Yep my system is of the cheap variety and when it switches modes there is a few ms of delay. I will have to live with it. shrugs
    – brand2000
    Aug 15, 2021 at 10:11
  • I would not call it cheap the inverters I have installed have all been fairly expensive, the closed transition are just very expensive.
    – Ed Beal
    Aug 15, 2021 at 16:05

The unit cannot anticipate the loss of AC power. Two things need to happen *based on the unit's price and functionality):

  • The inverter needs to "spin up" and start making AC power.
  • A physical contactor (simply a large relay) needs to mechanically throw from "utility" to "inverter". That contactor has a flight time while its mechanical components are moving. It must break contact with "utility" before it can make contact with "inverter" for safety reasons.
  • So it is a feature of this hardware, not a bug then. Thanks for taking the time to answer!
    – brand2000
    Aug 8, 2021 at 17:59
  • 1
    @brand2000 You could say that. It's possible to have "online" devices where it's on inverter/battery 24x7 and the utility power is simply a battery charger to keep the battery topped up. Those don't have a glitch, but they're more money. Aug 8, 2021 at 18:19
  • 1
    Yeah, top-of-the-line multimode inverters (such as Outback Radians or Victron MultiPlus/Quattros) have modes that lower the transfer time to the point they can act as a UPS, but it comes at a significant cost in standby consumption Aug 8, 2021 at 18:32
  • 1
    Keeping the inverter "spun up", I assume @ThreePhaseEel? My view is that it's perfectly fine to run loads straight off the DC side (battery pack), and if something needs power that badly, then do so, using its own (right-sized) 24x7 inverter if necessary. Aug 8, 2021 at 19:01
  • 2
    @brand2000 Yes, I would expect computers to glitch out and require rebooting. Hard to say with other stuff. There could also be voltage spikes from motor inductive kick, I'd have "whole house" surge suppression in there. Aug 9, 2021 at 1:17

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