How adjust the volts on an MCP655

[StAndrew]

Im looking at running my MCP655 at 13V. What do I need to adjust the volts between 12 and 24V?

[defect9]

you need this: http://www.koolance.com/water-coolin...roduct_id=1040

or, if you want to control two of them and have a handy bay-mounted control, you want this: http://www.koolance.com/water-coolin...roduct_id=1169

[StAndrew]

Awesome, thanks! Exactly what I was looking for .

[Martinm210]

FWIW, extra voltage on the D5 varios (MCP655 or PMP450) really has no practical benefit. It's not even measurable at normal to high restriction conditions most would operated them in:
pmp-450-pq24v.png

The D5 Strong (PMP450S) is the only one to really net gains from higher volts:


I wouldn't bother with the varios...just not worth it really. In average to high restriction conditions, you net the same hydraulic performance and dump more heat into the loop is all....so really a net loss.

[Stewie007]

Not to mention over-volting the motor for long periods of time results in premature failure of the pump.

[StAndrew]

I was only shooting for 13V. Last I heard, that was the best voltage for performance vs heat dump. Im running an EK top, what diff would that make over the stock top at diff voltage?

[earthwormjim]

I was only shooting for 13V. Last I heard, that was the best voltage for performance vs heat dump. Im running an EK top, what diff would that make over the stock top at diff voltage?

No difference at all. The pump is probably RPM limited, so performance does not increase at voltages above 12V.

The money spent on a buck/boost converter is not worth it at all.

[StAndrew]

The motor is designed to run at 24V so I dont see that being the issue. There may be some cavitation involved when the RPMs get too high

[Martinm210]

It is RPM limited, it probably varies a bit depending on the individual pump, but try it for yourself if you don't believe me. Measure the RPM at 12V, now increase it to 24V. The RPM will temporarily increase, but then circuitry will reduce it back down to the 12V level.

The only thing you get from higher volts on the varios is more heat dump and a hair higher RPM under very very low restriction conditions which is beyond the limit most systems operate under.

Under High to Average restriction the RPM and Hydraulic performance is exactly the same at 12V vs 24V or 13V or anywhere in between.

This is what I got for Voltage vs RPM (Green Line is Low Restriction Condition where max RPM is at 12.4V):
koolancepmp450s-rpmcomparis.png

A high restriction condition is even lower than that were 12V is equal to 13V or higher.

[earthwormjim]

The motor is designed to run at 24V so I dont see that being the issue. There may be some cavitation involved when the RPMs get too high

It's not just a motor. It's a motor, a controller and a voltage regulation circuit all packaged together. If the controller is programmed to limit the RPMs or to limit the total power consumption (balancing V and I and ultimately torque), then it is irrelevant what the motor is rated for. Also, just because a motor is rated to operate at a higher voltage, that does not directly translate to improved performance. It's entirely possible 24V is stepped down to 12V internally.

[eth0s]

It would be easier to add a second pump in series. Then you would get twice the head pressure.

[Conumdrum]

So. We is done here. Thanks Martin!