I replaced the stock 40mm fan in my ebike charger with a noctua

Maybe the OEM fan does PWM over the 12 volt line, instead of a separate line. Noctua doesnt accept that.

>>60654404
The voltage is probably so low the noctua doesn't spin up. A lot of these oem fans have stupid high rpms and sound like a buzzsaw, so they're run at extremely low voltages. Below start up for the noctua. Maybe? What happens with the oem connected to the battery?

>>60654467
oh that's interesting, I didn't even know that was possible, but it sounds like it could be the issue

The pwm is probably a failsafe to keep the charger from burning up, I'm assuming.

>>60654506
I tested the fan header with a mm and it came out to 12v

>>60654467
I can't seem to find any info about these types of fans

>>60654506
>What happens with the oem connected to the battery?

I'll have to check this out. I'm assuming the oem fan will spin up fine on 9v

>>60654744
Youll have to look with an oscilloscope to see if theres a squarewave. Then you know its using PWM.

>>60654766
>>60654744
A fix for this is to find another 12v point on the board and attach the fan to that.

>>60654766
can you point me at some two-pin fans that can operate via pwm

>>60654792
it's a bit risky considering I'm not an electronics expert and this thing outputs 60V. In fact I don't know what else would even be running at 12v besides the fan. Maybe the leds?

>>60654810
>Fan that runs on PWM
Dunno mane, most cheap fans do.

>>60654810
Also, the 12 volt for the PWM signal has to come from somewhere. Can you make a picture?

>>60654810
Pps: im just making assumptions about the pwm fan, dunno why the noctua wouldn't work otherwise

>>60654404
Traditionally for PCs there are 2 types of fans:
-3 pin ones for the case. Two pins are for voltage and the third one is a RPM sensor. They are voltage controlled.
-4 pin ones, which you use for the CPU. They have an extra pin for the PWM input so that the speed can be controlled more efficiently.

If you put a 3 pin fan in the cpu socket, they used to run at full speed. Some mobos might be able to actually voltage-control these as well.

Now a 2 pin fan is a different beast. I assume there is no speed sensor pin and the two pins are voltage ones. I bet my ass the charger is PWMing V+ and the noctua does not support it.