The strange noise starts at sec 6. before you can hear how the ac inverter is turned on and at the end the clicking sound when turning off.
The ac works. The sound is not very loud but loud enough to keep me from sleeping next to it. And it doesn’t sound very trustworthy.
to me it sounds like a short circuit but I am not sure….
Do you guys experience a similar noise when the inverter is turned on
Cheers
Hi @Morre
sadly i only hear the inverter turn on/off.
Is it a kind of buzzing sound maybe? Because thats totally normal
Erik
Hi Eric,
Thanks for the feedback.
You can hear the inverter turning n at around -11sec.
Then there is a short period without any sound an them at around -9sec the noise (clicking sound) starts till I turn off the inverter.
As I said, maybe this is normal. I just know that my old ac50 doesn’t make any noise when the ac inverter is turned on.
And I don’t have a second ac60p to compare…
Hello @Morre,
it sounds like a tickling vibration from the inductors of the AC inverter output stage.
When AC is on, the power-conversion stage uses high-frequency switching components to transform DC into an AC sine waveform, then to further smooth it it uses inductors which are basically wire loops that turns around a ferrite core, these inductors respond to the magnetic field inside their ferrite or laminated core which is rising and collapsing at the AC inverter switching rate (or at audible subharmonics of it).
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To confirm this, you will notice the tickling sound changing tone or volume depending on how much load the inverter is driving.
In most cases, this noise is just harmless proof that the filter inductors are doing their job; however, if it suddenly grows louder or rattles, a loose winding or mount might need inspection.
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Minor differences on these inductor’s winding tension, ferrite core, PCB mounting or component tolerances in general can cause two units of the same model to exhibit different levels of audible tickling noise, so I believe at the end is just about being lucky or not when it comes to inverters.
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As a personal opinion Bluetti units being very high quality units are not really expected to generate noticeable levels of AC noise, if your unit is grid connected note that internal inductors can also sounds differently based on grid power quality.
Hi @Morre, From the audio you provided, we haven’t found any issues. It sounds like the first clicking sound indicates the power is connected, and the second clicking sound should be turning off the input or output.
The AC60P will produce a current sound and fan noise when starting up.
Could you tell us what your specific load is?
In addition, the audio seems to have been recorded when very close to the AC60P. Normally, it won’t be placed this close while sleeping, so the noise impact shouldn’t be significant.
Thanks to @Selfmadestrom and @ndwr for their professional explanations—they are absolutely correct.
Hi there,
Thanks again for all the clarification.
Based on your feedback and insights, I ran some more tests.
Indeed, the noise changes to the load. It pitches higher with more load and at 63watt -give or take- it disappears.
I also know, that it is recorded close to the fan, but I can also hear it from a yard away (I am one of those people that can hear the Moskito repellent sound); and the frequency of the inverter is quite annoying…
Nevertheless, thanks again for the support to figure out the source of the noise.
Now it is up to me find a solution
All the best
Hi @Morre, Thank you for your updates and tests. Your rigorous testing has shared very valuable experience.
We agree that when the load power is too low, the fan speed is low, but it may be noisier instead.
In addition, when using a mobile phone or other devices for recording, additional electromagnetic interference noise may be generated.
We recommend placing the power station in a well-ventilated place away from the bed, which will not affect your sleep.