MCP35X on fan controller

[homefry]

Can the pump regulate speed off a 3-pin fan controller? I know the pump gets all its power from the molex.

Yes, I know the PWM is better.

[Martinm210]

Not through the little PWM connector.

If you had a pump controller capable of handling high loads, you can regulate via voltage control through the molex, but you don't get nearly the range as you do with PWM.

This chart shows that using voltage control, I could get down to about 40% PWM levels at 7.4V, but much lower voltage than that is where the pump starts having trouble starting.
http://img687.imageshack.us/img687/1503/35xpwmpqsummary.png
Voltage control is also a bit more risky, too high(>13V) or too low(<8V) and the pump will simply fail to start. That means bad news if you bump a control knob without knowing beyond the limits. PWM on the other hand will always run no matter what setting.

[QuadSLI]

Not through the little PWM connector.

I am new to PWM pump, so you are saying you cannot regulate the pump speed via PWM connector (while power from Molex PSU) from something like aquaero.. ???

[Martinm210]

I am new to PWM pump, so you are saying you cannot regulate the pump speed via PWM connector (while power from Molex PSU) from something like aquaero.. ???

Aquaero can through it's 4 pin PWM header, but it's more of the exception. Most fan controllers regulate fan speed by reducing voltage through a 3 pin output. You need a 4 pin PWM output to provide PWM signal.:up:

[shazza]

Thanks for this, Martin. This is a question I get a lot, and this will be a good reference.