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Battery making clicking noises

Warning Do not attempt any electrical or gas work yourself. Always use a qualified, MCS-certified, or Gas Safe registered professional for repairs.

What you’re seeing (symptoms)

Your battery or inverter unit is making a distinct “clicking” or “clunking” sound. This may happen occasionally, every few seconds, or specifically when the sun goes down or a high-power appliance is turned on.

What’s normal vs not normal

Normal:

Startup/Shutdown: A single or double “click” when the unit wakes up in the morning or goes to sleep at night.
Mode Changes: A click when the battery switches from “charging” to “discharging.”
Relay Operation: The sound of the internal safety relays (mechanical switches) closing or opening.

Not normal:

Rapid-fire Clicking: A sound like a machine gun (multiple clicks per second).
Loud Banging: A heavy “clunk” followed by the unit shutting down or displaying an error.
Continuous Clicking: Clicking that continues for several minutes without the unit actually starting to charge or discharge.

Likely causes (ranked)

Relay ‘Chatter’: The internal switches are trying to close but are immediately opening again, often due to a voltage fluctuation or a communication error.
Weak Grid Signal: If the grid voltage is marginal, the inverter may click as it repeatedly tries and fails to “sync” with the grid.
Firmware Bug: The internal software is getting “stuck” in a logic loop, causing it to toggle the relays unnecessarily.
Loose Connections: A loose wire inside the unit or at the smart meter is causing intermittent power loss to the control circuit.
Component Failure: One of the mechanical relays is physically worn out and can no longer stay closed.

Quick checks you can do safely

Listen for the trigger: Does the clicking happen when you turn on the kettle? Or when a cloud passes over the solar panels? This helps identify if it’s “load-based” or “generation-based.”
Check the app: Look for “Grid Under Voltage” or “Relay Fault” messages in your monitoring app.
Hard Reset: Switch the system off (both AC and DC), wait 2 minutes, and switch it back on. Does the clicking return immediately?
Check for heat: Without touching any electrical parts, feel the casing near where the noise is coming from. If it’s unusually hot, turn the system off at the breaker.

When to call an installer

If the clicking is rapid-fire or continuous for more than a minute.
If the system makes a loud “pop” or “bang” sound.
If the unit displays a “Relay Self-Check Fail” or “Grid Synchronisation Error.”

Questions to ask your installer

“Are the internal safety relays covered under the 10-year manufacturer warranty?”
“Can you check the grid voltage stability at the consumer unit to rule out nuisance tripping?”
“Does the inverter firmware need an update to fix relay chattering issues?”

FAQs

What is a relay? It’s a mechanical switch inside the inverter. When the inverter wants to send power, it sends a small electrical signal to a coil, which magnetically pulls a metal arm to close a circuit. That “pull” is the click you hear. Is clicking dangerous? A single click is normal safety operation. Rapid “chattering” can be dangerous as it causes electrical arcing, which generates heat and can eventually lead to a fire. If it chatters, turn it off. Why does it happen at sunset? As solar power drops, the inverter may “hunt” for enough power to stay on. It may click on, realize there isn’t enough power, and click off again. Modern inverters should have “hysteresis” logic to prevent this. Can it be fixed with software? Often, yes. Manufacturers can sometimes update the “timing” of the relays to make them less sensitive to minor grid fluctuations. Is it getting louder? If the clicks are getting louder or sounding “crunchier,” the mechanical parts of the relay may be failing and should be inspected by a professional.\n

Written by NetZeroNow | Last updated on 2026-03-02

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