EB3A fans noise - how is fix it!

I got tired of hearing the fan on the EB3a coming and going off and on, even in the silent mode. The wobbly noise is because of being unbalanced. My choices are 1. cut the wires to the fan and void the warranty. 2. Send it back to Bluetti for a replacement 3. Buy an external fan with metal ball bearings. As everyone could guess what option I took and now I have not heard the internal fan on, peace and quiet. Here is the link to the external fan.

Interesting solution! Do you plug that into one of the EB3A AC outlets?

correct and a multiplug on the second AC output plug.

While the fan was annoying for me as well at low speeds, I’m not sure (for me at least) it would be worth the additional overhead of always having the inverter on (which maybe uses ~25W plus 8W for the fan).

The EB3a uses pass-thru AC. I measured the AC input vs AC output and it was 45 watts in and 47 watts out using my Kiil-a-Watt meters. The EB3a has a UPS feature that does not use the inverter. Best thing about the EB3a !

Guess you never saw my posts about the fan noise. The noise you mentioned is not caused by the fan at all. The noise is generated by the fan voltage control circuit which buzzes. I replace my fan with two ball bearing fans of differing qualities and the buzzing never went away. The fan noise itself changed slightly and quieter but the throbbing buzzing was always still there.

Not sure why you would consider cutting one of the fan wires when the fan is simply plugged into the circuit board by a two pin disconnectable connector.

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First of all, cutting the wire was a joke. haha Second my external fan works perfectly, no noise from anything in the EB3a. I did not open the unit so where the noise came from is not the issue. Piece and quiet is what I need.

My point was that you’re sacrificing more power than usual to make this work making the system more inefficient in exchange for quieter operation.

You’re effectively forcing air in so that you don’t hit the temperature threshold that causes the internal fan to start spinning and cause the unwanted noise from the fan control circuitry.

That is true, I am using about 8 watts for the fan. So now how much wattage does the internal fan and all the circuits that regulate the fan use?

Hard to say other than the internal fan is spec’ed at 12V and 0.3A, so max of 3.6W. The circuitry probably adds a few more watts on top as well as 5W for the loudspeaker inside making those godawful noises :grin:


8 watts - 5 watts = 3 watts for piece and quiet. Sounds good.

I ended up 3d printing my own fan enclosure and using a 5V USB 60mm Noctua Fan. I didn’t want to void my warranty so I’m using it outside of the case.

I just opened my eb3a (EU version ) and the fan is 60mmx60mmx20mm. its 12V 0.15A !!! it’s different than yours guys.


I opened it and unplugged the fan. It’s as loud as a small vacuum cleaner for me, even when charging in silent mode.
I’ll either replace it internally with a more quiet one or just leave it plugged off and go for an external fan ( btw I think we should definately put some kind of dust filter)

Hope it stops the noises.

I see it’s a 3 pin fan but it actually just has 2 cables ( black and red , - + )
I need to watch out that the cable of the fan that I buy accidentally doesnt have the polarity reversed …

Edit: i cant even find such a fan. all of them are 60x60x25 mm. I’ll purchase the 25mm one and see if I can cram it in there, otherwise i give it back.
I dont like the external ventilation idea but it may be my last choice. Is there a huge ventilation difference between 5v 12v and AC?

Here is my solution.
Now it’s very quiet… :slight_smile:


That may void warranty as well. :laughing:

Brilliant, simply brilliant

Yes, we will all die… ;)

I forgot to mention I soldered a 390uF 63V cap parallel to the fan connector. Now the 100Hz buzz of the fan control PWM is off.

That’s amazing! My EB3A sometimes overheats as the fan refuses to turn on in UPS mode, and when it tries to charge it realizes it is too hot and goes into overheat mode and shuts down (fans don’t run when in overheat mode). This looks to be a control issue as fans do work when charging, but you have to enter charging before it overheats.

Non UPS low temp = fan off
Non UPS med temp = fan on
Non UPS high temp = fan off (overheat shut down)
UPS any temp = fan off

So if it enters high temp while in UPS mode, it will go straight to high temp shut down when it tries to eventually charge and never run fan to try to cool down.

This happens to me when ambient is 32C