AC200Max Fan noise fixed

achernikov · July 20, 2024, 5:23am

Hi there. Just wanted to share my experience with AC200Max and its fans.
The left fan kicks in once in a while and has a rattling / whiney noise that irritates me during the night.

I’ve purchased an 80x25 Noctua NF-A8 FLX, cut the power wires from the stock fan and patched my Noctua fan to the stock connector using scotchlok. I used an extension cable that came in the box for Noctua to keep the factory connector intact (say in the event of using this fan elsewhere or using another fan, I simply unplug the fan from the extension cable).

Fan is now dead silent and it even runs in shorter periods of time as Noctua seems to provide more airflow, whilst having lower RPM.

Next step is to change the fans on T500 and D050s

Selfmadestrom · July 20, 2024, 2:44pm

Hi @achernikov

Thanks so much for your detailed inside. The “Fan Problem” was discussed many many times on here. Would also love to see your T500 upgrade. I also have 2 of them.

Snips1 · July 20, 2024, 3:33pm

Hello, it may be interesting for you to look in the hidden menu of the ac200max temperature measurements, when your ac200max is charging and your noctua is running at full speed, to see the maximum temperatures inside.

Ps Also interested in the t500 and d050s mod!

achernikov · July 20, 2024, 4:26pm

Hi there. I am not sure if Noctua is running at full speed (most likely not), but here’s the screen for while it’s charging at 800W through solar and 500W through AC port.

achernikov · July 20, 2024, 4:30pm

As for the d050s mod, I lurked through the forums and it appears that both t500 and d050s use a 50x15 fan. A person used gelid silent 5, so I ordered five of these (2 for my t500, 1 for my d050s and 2 for my friend).

Snips1 · July 20, 2024, 5:04pm

Thanks !
I will try to charge my Ac200max this evening with 2 x T500 (900/1000w) and when the fans (“genuine”) of the Ac200max are running at full speed, I will record the temperatures and I will post on the forum to compare.

achernikov · July 20, 2024, 5:33pm

Interesting. Worth mentioning that the ambient temp here at the moment of photo-ing was 28 deg C

Snips1 · July 20, 2024, 9:15pm

27°C in the room
The hotest that a have :

then the fan wake up and the temperature drop.
There’s not a big difference.

achernikov · July 21, 2024, 10:56am

Thanks! Seems like we’re not that far off each other, which I assume is great news for the new cooler fan.

Snips1 · July 21, 2024, 11:21am

Yes ! (And your ambiant temp is hotter than mine)

DJR · July 21, 2024, 7:53pm

Been enjoying following this post about the AC200Max.
Could someone tell me how to access this hidden menu as shown in the pictures please?
Cheers

achernikov · July 21, 2024, 8:01pm

Data - bms - tap on the top left corner quickly 5 times with a beep

DJR · July 21, 2024, 9:26pm

Thanks, much appreciated and will give it a go.

achernikov · August 1, 2024, 6:53pm

Hi! I’ve just quickly changed the old fans in T500 to two Gelid silent 5 with the following logic:

Cut the cable of the stock fan, leaving the connector attached to the board
Holding gelid connector with the protruding plastic facing towards you: Connect middle of Gelid 5 to the red wire of the stock fan. Right of the Gelid 5 to the black wire of the stock fan
using scotchlok UY like this:

image478×600 60.3 KB
Have fun. I haven’t measured the temp yet, but the airflow is quite nice and not very hot.

Selfmadestrom · August 2, 2024, 9:25am

Thanks for your update :)

ThermoPV · July 23, 2025, 11:36am

Sorry to necro this thread but I’m looking to do a similar fan replacement to reduce the AC200Max horrible fan noise and I just happen to have these exact same Noctua 80mm fans lying around. I was considering using them for both 1st and 2nd stage fans (a bit of modding needed to the 2nd stage brackets needed to use a 25mm fan).

Did you ever manage to test them under max output load. I’m concerned they wouldn’t be able to cool the AC200 down when pushing 2,200w output or worse its 4,800w surge output.

achernikov · July 23, 2025, 11:51am

Hi! I’ve used this inverter in the extreme summer heat (I have no AC where Bluetti is placed) with 1500-2000 load powering through for about 20-30 minutes regularly and haven’t had an issue with overheating. However, I have replaced just the left fan and haven’t touched the slimmer right one. YMMV, of course, but I’d start with just swapping the left one. It is quite reversible if you don’t cut too much wire

ThermoPV · July 23, 2025, 1:02pm

Thats brilliant thank you. I’ll replace ethe 1st stage and see how it goes.

ThermoPV · July 24, 2025, 3:49pm

I replaced the 1st stage fan with the Noctua 80mm fan and the result is amazing. I can finally sit in the same room as the AC200 Max for the 1st time in 2 years.

Also having now gotten access to the hidden menu its confirmed a strange fear I had about my AC200 Max. When only one AC outlet is in use (200W draw) the ‘A’ temp on the screen was 54c-57c and the 2nd stage fan was starting full blast. When a 2nd AC load is added so 2 plug sockets are outputting (only a few additional watts needed on 2nd outlet) the 2nd stage fan never runs and the ‘A’ temps show 40c-43c and the battery appears to be draining slower. Something very odd happening with my AC200Max.