Hi, you may have received the software update. Please try to update the firmware and test. If you have any updates, feel free to let me know.
Hi @BLUETTI_CARE,
I have only received the BMS firmware and am currently at
BMS V1033.06
The bahavior of the battery discharge down to 99% and fans kicking in high for half a second or so and then settling at “Silent charging speed” is the same.
ARM v2073.03
DSP v2077.05
Kindest regards,
Jakub
ARM: v2074,05
DSP: v2078,05
BMS: v1033,06
@jakubx80 The firmware is the latest one. After updating the firmware, although the fan still starts, it should be started at a relatively low speed. This is to keep the internal temperature of the machine from rising too quickly (as explained before, although no load, the inverter is also on standby, so the internal temperature will increase.AC180 Noisy Fan Operation - #42 by BLUETTI_CARE) so that the fan will not start making noise at a sudden high speed as before.
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Well, I hardly notice that the fan sounds less. If it sounds a little less, it is not noticeable.
But the shutdowns/startups every 5 or 10 minutes are still happening, can’t you program this so that instead of shutting down/starting every x minutes the fan is constantly on but at a very low RPM generating less noise and also cooling the unit better than with these constant shutdowns/startups…?
@BLUETTI_CARE I can’t notice any difference from before and to my ear the fan doesn’t just start at slow speed. It “spikes”, then dips and then gains a “whine”.
Maybe my unit is just bad?
I uploaded the “fan” startup to YouTube, hopefully, you can view it.
Can someone in this thread watch it please and share with me whether you experience a similar fan startup sound?
This clip was done with AC180 plugged into wall but otherwise with no loads attached and both DC and AC outputs off.
~I apologize for my dog walking around making clicking noises 
Exactly! It’s exactly the same for me, it is very annoying to hear that fan noise spike!
There must be a more reasonable solution.
I prefer the fan to be ALWAYS running but at a very low RPM and therefore not sounding or annoying, but that in turn, for sure, helps to cool and preserve the electronics better than with these constant fan on/offs.
By the way, another question, the internal component that needs to be cooled with these fan on/offs, is there any way of knowing its temperature? Are the fan on/offs associated with a thermal sensor that indicates that it needs to be cooled?
@bluetti_curichinatogmailcom @jakubx80 I have sent the details to the tech team. If there is further update, I will let you know ASAP.
@jakubx80 The R&D department has tested the machine with upgraded firmware, and the test results show that there will not be too much noise. How long is the interval between each “sudden start” of your AC180 fan?
@BLUETTI_CARE that’s good to hear! I can’t wait to receive the new firmware.
The intervals are as follows:
Start to start is 44 mins
Duration 6 mins
Power draw 262W
What is the latest version of firmware to fix the nosy fan issue?
I updated the AC180 and my versions are:
ARM 2073.03
DSP 2077.05
BMS 1033.06
SER: AC1802316002058565
From 100% to 99% with a 3 watt DC load the fan starts and it is not at a low speed and it is set to Silent Mode.
This is noisy in a quiet bedroom
Air intake is 74F and exhaust is 84F
Thanks
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@jakubx80 We can change the fan to start once every 4-5 hours or so. The fan speed remains unchanged, still at 50%. What is your opinion?
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@BLUETTI_CARE I think that as long as the battery would not get depleted significantly by what I’m assuming is less frequent recharges, then the start every 4 to 5hrs would be an improvement.
However, I’m completely puzzled by why you can not operate the fan more frequently but let’s say at 20% speed?
The problem is it’s a noisy fan, and noise increases with fan speed. Therefore, the fix to the problem would be to run the fan where it’s the lead noisy - low speed.
@jakubx80 I will forward your comments to the R&D department to discuss the feasibility. If I have any update, I will let you know.
Can you have the fan run at 25% all the time or when needed? That should be less loud
@bluetti_brian2022 @jakubx80 Our R&D department is still testing, if there is a new firmware, I will notify you as soon as possible.
Hello,
Are you going to release any updates soon? I still have the noisy fan problem and I have AC180 in a bedroom and I am very tired of its noise. 
@Q.E.D @bluetti_curichinatogmailcom A new firmware for improving fan noise may be update within a week. You can pay attention to the update.
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