The fan noise of my MultiPlus-II 48/5000/70-48 makes it impossible to charge batteries at night. However, turning off the internal fans via the fan wizard makes the unit too warm for my taste.
Since I didn't want to open the unit to void the warranty, I made an adapter to install two 120 mm fans on the bottom panel to force airflow through the unit while the internal fans are disabled via the fan assistant.
The Noctua fans used are virtually inaudible and simply run 24/7 and so far I am happy with the performance and noise of the unit. The device does not even get hand-warm at 4000 watts inverter power.
I use my Orion-Tr 48/12-9 to provide the 12 V for the fans.
Attached is a Photo Love Story of the installation.
.stl file to print yourself (or have printed) after the images.
I will gladly take feedback if the adapter also fits other devices like the MultiPlus-II 3000 or the Quadro-II. I have no other device to test here, unfortunately.
There is a conversion kit for the fan control of the internal fans of older devices. You might want to take a look here.
https://community.victronenergy.com/questions/108663/victron-multiplus-ii-noise-level-what-is-your-expe.html?childToView=191439#answer-191439
My device has the modification already from the factory, so I do not know the original noise level. But if the device is even louder without... God have mercy.
I built this adapter because even with the conversion kit, the volume of the internal fans is an intolerable.
Fresh from the Printer. PLA @ 220 °C, 70 °C bed, 0.4 mm layer hight and 40 % infill. Used support material for more than 60% overhang.
Ready to use.
Fan is inaudible even without dampeners.
Used 3x16 mm wood screws and 4.3 mm washers to install the fan shroud.
The wood screws are screwed directly into the 2.4 mm holes in the PLA.
Works as intended. Only a gentle 50 Hz hum can be heard when the MultiPlus-II is under full load.