I’ve bought multiple 2-pin fans and they are not compatible with the board.
Moreover, I’ve bought JST XH2.54-2P, JST 2 pin mini, JST SM 2 pin connectors, and neither is compatible.
Looks like most fans are coming with JST SM 2 / JST XH2.54-2P.
Please help, I’m desperately trying to find exact fan header connector type.
I can’t answer what the connector is, but as indirect help: use a tiny screwdriver to depress the ratcheting ‘teeth’ that hold the metal barrel connector you have to release them. Put the plastic to the side and just slide the pins for +VDC and 0Groound (probably red and black) right over the ViisionFive connectors.
This assumes that your warranty is expendable and the fans you ordered are electrically correct.
Good luck!
The schematics say it is a SMD-2P-2MM_90, which basically means a surface mount 2pin connector with a 2mm pin spacing, without giving any more specifics.
Visually, it’s a JST connector, but the ones you list are 2.54mm not 2mm. 2.54mm is the standard pitch used on the GPIO header and many pieces of equipment; and is based on an an old imperial measurement. But 2mm is quite common in modern electronics.
Something like this:
…but maybe with the +ve -ve lines reversed from standard. As @RiscVFan says, you can carefully pop out and replace the pins in the correct orientation, or cut and solder them.
Funny. I’m in one of those imperial-using countries (Not Liberia nor Myanmar) and have some JST-PH 2.0mm connectors for free that I’ve been dying to use … and can’t find a use for because here the 2.54 and 1.27 mm pin widths are just everywhere. 
The fan is plain ole DC. If the connector just had the pins swapped, the motor would blow backward, sucking instead of blowing. (Don’t be juvenile. ) There are pneumatic and dust reasons that backward might not be ideal, but most of us would recognize the connector as fitting and the motor as “just” blowing the wrong way - well, honestly, if we even noticed it at all on a chip this size.
I haven’t put a fan on my V5R2, but on my V5R1, the pins were just loose, allowing us to easily connect them to the (buffered, higher current) voltage sources on the 40-pin connector. So if you pop the pins out of the plastic shell, perhaps that’s another destination for them.
You have to solve the mechanical (make it fit) AND the electrical (find a source of voltage at the rated current to make the fan go spinny spin) to make the motor go brr.
Of all the things we connect, fans are probably the most forgiving to anyone willing to work through it, but it can be a bit of slugwork. Good luck!
No, it’s a DC brushless motor with a controller chip on board. A reversed connection results in no rotation and, at worst, a dead fan.
I thought this was really cool:
Toroidal CPU fan prototype
The design is off because it was tuned to the destined ideal cpu fan rpm speed for optimal sound reduction
and optimal air movement. The idea however is sound.
How about a VF2 toroidal cpu fan? It’s not my specialty, but I figured I should throw it out there to the universe to see if anybody else resonates with this and goes with it.
I’ve got Odroid XU4 fan but I wasn’t able to find a suitable connector for this board. So what I did is to strip the wires and connect them directly, and fix them in that socket myself:
I’ve finally set up coller for my VisionFive.
It is exactly 2P PH2.0MM, I’ve ordered bunch of them on aliexpress.
Polarity on the header seems flipped, so I’ve connected red wire to black and vice versa.
I used a JST XHP 2 pin plug crimped to a 5V fan. The arrow (pin1) on the silk screen points to the 5V connection.
I just got a bunch of JST PH2.0MM, however, after a few seconds of plugging it to the fan connector and then shutting down my board, the fan won’t stop. I rarely shutdown the board, but I still prefer it to stop the fan while the board is powered down, so I returned to use 3.3V GPIO pin. Yep, the 5V fan on 3.3V spins slower, but also makes less noise, and it stops when the board is powered down, that is what I want.
