[RE-wrenches] pump questions

[David Katz]

The efficiency is higher at higher voltage.
David Katz

Sent from my iPhone

On May 30, 2013, at 7:12 PM, "Jesse Dahl" <dahlsolar at gmail.com<mailto:dahlsolar at gmail.com>> wrote:

I was reading up on the SQF pump and do remember seeing something about efficiency at higher voltages.  Can't remember if it got better or worse.

Jesse

Sent from my iPhone

On May 30, 2013, at 6:44 PM, Allan Sindelar <allan at positiveenergysolar.com<mailto:allan at positiveenergysolar.com>> wrote:

Todd,
The SQF runs on 30V or more, but is happiest above 90V according to Grundfos, and I have never heard anything suggesting a disadvantage to the higher voltages.

I think the 1400 watts is a theoretical maximum, and the pump will vary its operation and output according to the available wattage (not the available current). Most SQFs effectively max out at around 800-900 watts. In fact, my pump curves on the 11SQF-2 max out at 900 watts at 300' of head.

You'd probably do just fine with a single series string of 10-12 modules.

What I don't know is to what degree you need to worry about low temperature VOC limits; I'd be careful about getting too close to 300V.
Allan

Allan Sindelar
Allan at positiveenergysolar.com<mailto:Allan at positiveenergysolar.com>
NABCEP Certified Photovoltaic Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder and Chief Technology Officer
Positive Energy, Inc.
3209 Richards Lane (note new address)
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com<http://www.positiveenergysolar.com/>


On 5/30/2013 4:29 PM, Todd Cory wrote:
this question is part 2 about the customer with the used astropower 75 watt modules -

he has a grundfos 11sqf-2 already set by the well driller. the input specifications for the cu200 pump & controller are 30 to 300 vdc, 1400 watts, 8 amps.

this will initially be running array direct and i am trying to figure out the wire loss from the modules to the cu200 controller. to do that i need voltage and current numbers. im assuming the higher the voltage the lower the running current?
from the specs above: 1400 watts divided by 8 amps = 175 volts... so if i feed this with closer to 300 volts would that mean the running current would drop to around 4.6 amps?

thanks for the help,

todd





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