What you will see
- LED lamps shimmer or pulse during battery operation.
- Lights dip when an AC, refrigerator or pump starts.
- Only a particular lamp or dimmed circuit is affected.
- Several lighting circuits fluctuate together.
Why it happens
Lighting equipment, dimming controls and variations in the incoming supply can all contribute to flicker. The compatibility of an LED lamp or driver with its dimmer is particularly relevant when dimming is involved.
If flicker follows the starting or stopping of another appliance, that timing gives the installer a useful reason to examine changes in the supply. Measurements can help establish whether the disturbance originates with a load, the supply arrangement or another electrical issue.
For troubleshooting, one affected fitting suggests starting with that fitting and its controls. Several circuits changing together calls for checking their shared supply as well. Neither observation identifies the fault by itself.
The pattern points where to look
One fitting
Start with that lamp, its driver and any dimmer.
Dips as an appliance starts
Look at how the supply changes at that moment.
Several circuits together
Check their shared supply as well.
Crackling, a burning smell, scorching or unusual heat: stop using that equipment where safe and get prompt electrical help.
Safety box. If flickering comes with a burning smell, buzzing or crackling from the DB, warm switches or sockets, or lights in one room going very bright while others dim, switch off at the main breaker and call a qualified electrician. Those signs point to a loose or failing connection, often in the neutral, which can overheat and damage appliances. See our burning smell guide. Do not open the inverter or the DB yourself.
What the problem means
Bulbs and fans respond to the voltage they receive. When it dips or rises, even for a fraction of a second, LED drivers react and you see a flicker; fan motors speed up or slow down.
With a hybrid inverter, your loads may be fed from the grid (passed through the inverter), from the inverter's own output using solar and battery, or a mix. Each source can cause voltage changes for different reasons, so the first job is to find out when it happens.
Lights flickering
Voltage dips
Heavy loads starting
Transfer
Changeover between grid and battery
Loose joint
Wiring connection
Quick-check table: bulbs flickering on inverter
| Symptom | Likely cause | Safe owner check | Call an engineer if... |
|---|---|---|---|
| Flicker only while the grid is on; neighbours see it too | Grid voltage fluctuation passing through the inverter in line or bypass mode | Read grid voltage on the inverter screen or app | Voltage often goes outside the normal range |
| Single blink when load-shedding starts or ends | Transfer between grid and battery | Note if it matches load-shedding times | Computers or routers restart every time |
| Dip each time the water motor, AC or iron starts | Starting surge pulling voltage down | Start the load with others off and watch the lights | Dips are deep or the inverter beeps or trips |
| Flicker gets worse as the battery runs down at night | Battery near low-voltage cut-off, inverter output sagging | Check battery percentage and voltage in the app | It happens with a healthy battery |
| Lights pulse on sunny afternoons, inverter keeps reconnecting | Grid voltage rise tripping the inverter repeatedly | Check the app's event log for grid over-voltage | Trips happen most sunny days |
| Some lights very bright, others dim, appliances behaving oddly | Loose or broken neutral | Switch off at main breaker | Immediately |
| Only one bulb or one room flickers | Faulty bulb, loose holder, switch or dimmer | Swap the bulb for a known good one | Swapping does not fix it |
| Flicker only on generator | Generator voltage or frequency unstable | Check generator speed and load | It persists with a healthy generator |
Common causes of lights flickering with solar inverter
Grid voltage passing through the inverter
In many hybrid inverters, when the grid is present, the inverter passes grid power through to your loads (often called line, bypass or utility mode). In that mode the inverter does not regulate the voltage, so every grid sag and swell reaches your bulbs. This is the most common cause of voltage fluctuation solar owners notice, and it is not a fault in the inverter. Our guide to inverter bypass mode explains when inverters run this way.
Some inverters let an engineer choose a narrower AC input range, so the inverter switches to battery sooner when grid voltage is poor. That steadies the lights but uses more battery. A grid-side voltage protector protects against high and low voltage, but it disconnects rather than smooths, so it will not cure flicker on its own.
Switching between grid and battery
When load-shedding starts, the inverter takes a few milliseconds to switch to battery. Most lights and fans ride through it; some LED bulbs blink. Our transfer time guide explains the UPS and appliance settings.
Heavy loads starting
Motors, AC compressors, irons and kettles pull a large current, and a motor pulls several times its running current for a moment as it starts. On battery, the inverter must supply all of it, and the output voltage dips. On a weak grid or a long, thin cable, the same happens on grid power. See inverter overload and beeping if the inverter also beeps or trips.
Low battery
As a battery nears its cut-off, the inverter's output can sag under load, especially when something heavy starts. Our battery low voltage alarm guide covers cut-off settings.
Voltage rise and repeated reconnection
On sunny afternoons, an exporting inverter can push the local voltage over its limit, trip off, wait, reconnect and trip again. Each cycle changes the voltage your lights see. See grid voltage rise.
Loose connections and the neutral
A loose connection at the main switch, meter, inverter output or DB causes flicker that gets worse with load and can heat up. A loose neutral is the most dangerous version: voltage shifts between circuits, so some lights brighten while others dim. In three-phase homes, uneven loading on the phases makes this worse; see phase imbalance.
Fans speed changing on solar
Ceiling and pedestal fans run faster on higher voltage and slower on lower voltage. If fan speed rises and falls with the grid, the cause is the grid voltage in bypass mode. If it changes only on a generator, the generator's frequency or voltage is drifting; see generator not working with inverter. Some electronic fan regulators also react to small voltage changes more than old step regulators.
Safe owner checks, step by step
- Note when it happens. Grid on or off? Day or night? When a particular appliance starts? Only on sunny afternoons?
- Read the inverter screen or app. Look at grid voltage, output voltage, load percentage and battery level when the flicker happens. Photograph the screen.
- Ask your neighbours. If they see the same flicker without solar, the grid is the cause.
- Start one heavy load alone and watch the lights.
- Swap a bulb if only one fitting flickers.
- Do not open the DB, the inverter or any cable joint. If you see heat, discolouration or smell burning, switch off at the main breaker.
- Send your notes and photos to your installer.
What an engineer will check
- Grid voltage over time, ideally logged for a day or more, at the supply and at the inverter.
- Inverter output voltage under load, including when motors and ACs start.
- All terminations: main switch, meter, changeover, inverter input and output, DB busbars and neutral links. Loose or heat-damaged terminals are re-made or replaced. See breakers and protection.
- Cable sizes from the meter to the inverter and from the inverter to the DB.
- Inverter settings: AC input range, transfer mode, battery cut-off and voltage response settings.
- Load sizing: whether heavy loads should move to a grid-only circuit or start at different times.
- Power quality in commercial or factory sites, where drives and rectifiers distort the supply. See harmonics and power quality.
How to prevent it
- Keep heavy loads such as motors and non-inverter ACs off the backup output, or stagger their starts.
- Size the inverter with surge headroom for the motors you run.
- Ask your installer to set the AC input range and transfer mode to suit your grid and your appliances.
- Have DB terminals and neutral connections checked during routine maintenance.
- Before adding a stabilizer, read stabilizer with solar inverter; the wrong placement causes more problems than it solves.
How Solar Works Pakistan handles flicker complaints
For systems we install, WhatsApp 0336 666 4321 with a photo of the inverter screen or app at the time of the flicker, the inverter model, and your notes on when it happens. Our own engineering staff handle the complaint, and we target sending service personnel within 48 hours of a registered complaint to begin diagnosis. Our 1-year service warranty applies under the applicable project terms; see how after-sales service works.
We can also investigate flickering and voltage problems on systems installed by other companies, as a chargeable service, across Punjab.
Frequently asked questions
Why are my lights flickering with solar inverter on grid power?
Most hybrid inverters pass grid power straight through when the grid is present, so grid voltage swings reach your lights. If neighbours see the same thing, the grid is the cause. An engineer may adjust the inverter's input range so it moves to battery sooner.
Is voltage fluctuation solar related or a WAPDA problem?
Usually it is the grid, passed through the inverter. Solar can add to it on sunny afternoons through voltage rise when exporting. The inverter's voltage readings and event log help tell the two apart.
Why do bulbs flicker on inverter during load-shedding?
A single blink is the transfer from grid to battery. Repeated flicker on battery usually means a heavy load is starting, the inverter is near overload, or the battery is close to cut-off.
Why are my fans speed changing on solar?
Fan speed follows voltage. On grid power in bypass mode, grid voltage changes show up as speed changes. On a generator, unstable frequency or voltage is the usual cause.
Can flickering lights damage my appliances?
Brief dips from a motor start are mostly harmless. Large swings from a loose neutral can damage electronics and are a fire risk, so switch off and call an electrician if some lights go very bright while others dim.
Will a stabilizer stop lights flickering with solar?
Sometimes, but it depends where it goes and what it feeds. A badly placed stabilizer can confuse the inverter. Read our stabilizer guide before adding one.
Sources
- Hunker, what causes lights to dim and then brighten (open neutral, large appliance start-up, loose connections)
What you can check yourself
- List the rooms and light fittings affected.
- Note whether the flicker is visible directly or only in a phone recording.
- Record whether it occurs continuously or when a particular appliance starts.
- If a dimmer is installed, observe whether the symptom changes at a different normal brightness setting.
- Photograph inverter warnings and note the battery status when the problem occurs.
What not to do
- Do not open fittings or distribution boards, tighten live connections or alter neutral and earth wiring.
- Do not add improvised electrical components to suppress flicker.
When to call us
- Persistent or widespread flickering needs investigation. If it accompanies crackling, a burning smell, visible scorching or unusual heating, stop using the affected equipment where this can be done safely and seek prompt electrical assistance.
- An inspection may involve the lamps and controls as well as the backup supply. Replacing the inverter should follow evidence of a fault.
Flicker checks in Faisalabad and Lahore
Our Faisalabad and Lahore teams look at the lamps and controls as well as the backup supply, so any change is based on evidence rather than guesswork.
Send us
The inverter model, affected light types, whether dimmers are fitted, the timing of the flicker, and your city and area. Mention any recent electrical or lighting changes.
Technical references
Reviewed 25 September 2026. Manufacturer documents are cited for general principles; your exact model’s manual always applies.