# Lamps flicker when turn on the air conditioner **URL:** \ **Category:** DIY\ **Tags:** pv\_inverter, beginner\ **Created:** [22 June 2026 19:20 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589 "2026-06-22T19:20:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [22 June 2026 19:20 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/1 "2026-06-22T19:20:06Z")
Hello. As the title suggests, when the air conditioner starts, the lights flicker continuously. My setup is as follows: 2 x 3kV MultiPlus II inverters, a 10kW battery, and 25mm2 x 50cm cables. How can I fix this? Thanks everyone. ---
**Author:** ![Buzzy](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/buzzy/32/54803_2.png) [@Buzzy](https://community.victronenergy.com/u/Buzzy)\ **Post date:** [23 June 2026 02:34 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/2 "2026-06-23T02:34:46Z")
What is the power consumption of the air conditioner? It should be on the nameplate/certification sticker. Where are these 25mm2 cables? eg between battery and a Multiplus II ? Or output of a Multiplus II and the A/C? ---
**Author:** ![BAnders](https://avatars.discourse-cdn.com/v4/letter/b/dbc845/32.png) [@BAnders](https://community.victronenergy.com/u/BAnders)\ **Post date:** [23 June 2026 04:19 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/3 "2026-06-23T04:19:48Z")
Please add a wiring diagram or picture of the actual setup. A 3kVA unit can handle up to 2400Watt but the higher the temperature, the lower this gets. Also. Are the units in parallel setup or split phase? You can also look at the battery load and voltage in VRM → Advanced and then add a graph. But perhaps it isn’t a load issue, but power factor or something else.. For now it’s like calling a Doctor and saying I have an itch. Can’t help without more info. ---
**Author:** ![VerreyckenGerd](https://avatars.discourse-cdn.com/v4/letter/v/2acd7d/32.png) [@VerreyckenGerd](https://community.victronenergy.com/u/VerreyckenGerd)\ **Post date:** [23 June 2026 13:55 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/4 "2026-06-23T13:55:04Z")
Sounds like an overload situation. Any red lights flickering on the MPII’s during this phenomena? ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [24 July 2026 21:38 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/6 "2026-07-24T21:38:05Z")
Good evening, sorry for the delay in responding. My air conditioner consumes about 1kW/h and uses inverter motor technology. ---
**Author:** ![Buzzy](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/buzzy/32/54803_2.png) [@Buzzy](https://community.victronenergy.com/u/Buzzy)\ **Post date:** [24 July 2026 21:55 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/7 "2026-07-24T21:55:45Z")
No worries. During the peak current for startup, 1.5x to 2x more power needed, so that’s easily 2kW, which is most of the capacity of one MPII 3kVA. Have you measured it’s peak startup current with a clamp AC current meter? or checked the specifications on the electrical certification plate? ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [24 July 2026 22:17 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/8 "2026-07-24T22:17:58Z")
![image](https://europe1.discourse-cdn.com/victron/original/3X/6/5/65af7feef942301c64599391d8392e0cfae95fb5.png) Hello, this is my configuration ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [24 July 2026 22:21 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/9 "2026-07-24T22:21:25Z")
Thanks for the reply. I have two 3kVA inverters = 6kVA. And in any case, it doesn’t just do it at peak power, but almost all day, when the air conditioner is on. ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [24 July 2026 22:33 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/10 "2026-07-24T22:33:41Z")
Hello, no overload and no warning light, the inverters are 2x3kva=6kvA I only use 1kw/h for my air conditioner. ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [24 July 2026 22:51 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/11 "2026-07-24T22:51:56Z")
Hello, I have 2x3kva=6kva and 10kw of lifepo4 battery. ---
**Author:** ![Frisianstar](https://avatars.discourse-cdn.com/v4/letter/f/a5b964/32.png) [@Frisianstar](https://community.victronenergy.com/u/Frisianstar)\ **Post date:** [25 July 2026 07:39 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/12 "2026-07-25T07:39:04Z")
Cheap made inverter airco can put voltage spikes on the grid or have bad Power-factor; it’s possible that the Victron inverter does not handle this properly. Air-conditioners from well known brands do not have this problems. Inverter airco does not have inrush-current they start the compressor gradually. ---
**Author:** ![DuivertNL](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/duivertnl/32/279_2.png) [@DuivertNL](https://community.victronenergy.com/u/DuivertNL)\ **Post date:** [25 July 2026 09:13 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/13 "2026-07-25T09:13:46Z")
Exactly that, never had any problems with our LG aircon running on 1ph of 3ph multiplus 2 5k setup could also be just bad quality led lights, i see that a lot ---
**Author:** ![nickdb](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/nickdb/32/51440_2.png) [@nickdb](https://community.victronenergy.com/u/nickdb)\ **Post date:** [25 July 2026 13:10 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/14 "2026-07-25T13:10:19Z")
You mean 10kWh? What battery/bms is it? What are it’s specs and, if managed, the ccl and dcl? Inevitably, the battery can be the source of these problems. With parallel systems, you can also have asymmetry. Have you checked that they are balanced? I have a flow in the nodered section that can show this in realtime. > [@Node red show parallel system stats](https://community.victronenergy.com/t/node-red-show-parallel-system-stats/6143): > > Copying the post from the archive: I wanted to share a flow I created that shows master and slave inverter stats, and any imbalances. You will need to edit the “cerbo” mqtt endpoint to point to the IP of your own system or just use localhost (127.0.0.1). Device ID’s are fixed values for every installation. See the note in the flow. The defaults for single (L1) phase will work. Additional phases can be added using the mapping provided. The flow uses dashboard 2.0 (flowfuse/node-red-dashboard… ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [31 May 2026 21:57 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/15 "2026-05-31T21:57:57Z")
Good evening, I’m having a problem with my MultiPlus II inverter. When I connect loads above 1 kW, I get a voltage surge lasting about 1/2 second. Nothing happens, the inverter works normally, but it’s annoying and unhealthy for my electrical appliances. How can I fix it? Thanks. ---
**Author:** ![ejrossouw](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/ejrossouw/32/1610_2.png) [@ejrossouw](https://community.victronenergy.com/u/ejrossouw)\ **Post date:** [1 June 2026 06:17 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/16 "2026-06-01T06:17:47Z")
@ You will have to provide more information and VRM graphs would definitely help. What types of loads, size of system cabling, size of system, battery etc. ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [22 June 2026 19:06 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/17 "2026-06-22T19:06:22Z")
Hello, I have 10kw of battery, cable sez. 35mmq, for 0,50cm long. Thank you. ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [22 June 2026 19:07 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/18 "2026-06-22T19:07:15Z")
I have 2 multiplus ii from 3x2 6kva. ---
**Author:** ![ejrossouw](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/ejrossouw/32/1610_2.png) [@ejrossouw](https://community.victronenergy.com/u/ejrossouw)\ **Post date:** [25 June 2026 06:55 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/19 "2026-06-25T06:55:35Z")
To liitle information for me to be of much help. Try to identify the source e.g. specific device that causes it, ensure all the connections are well crimped and tightened to specification. While limited with min 1min intervals to capture data, use VRM graphs to look at the system parameters overall to identify e.g. anomalies in battery performance at the time etc. ---
**Author:** ![lxonline](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/lxonline/32/25567_2.png) [@lxonline](https://community.victronenergy.com/u/lxonline)\ **Post date:** [25 June 2026 14:57 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/20 "2026-06-25T14:57:47Z")
Sometimes a particular load chops ths sine wave and makes something like that an issue. Or a pump control. Adding an SPD will help if you can’t fid the source. Other times its actually a loose connection. One system i found had a lights flicking brighter and dimmer issue, i found a change to the correct gauge ac. Wiring was the solution ( they were running 2.5mm on a 5kVa. Very undersized.) ---
**Author:** ![erjoli](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/erjoli/32/48515_2.png) [@erjoli](https://community.victronenergy.com/u/erjoli)\ **Post date:** [24 July 2026 21:21 UTC](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589/21 "2026-07-24T21:21:57Z")
Hi, sorry for the delay in responding. The cables are 25mm², I have two 3kVA inverters in parallel and two 5kW batteries = 10kW total. The voltage fluctuations (flickering) happen even with just the 1kW air conditioner. I checked all the terminals and they are tight. I previously had a low-quality Chinese inverter and this problem didn’t occur. Where should I place the SPDs? On the DC side, at the solar panel input, or on the AC side? Thank you very much. [Next page](https://community.victronenergy.com/t/lamps-flicker-when-turn-on-the-air-conditioner/59589.md?page=2)