DC pumps:huge power savings, really?

[mark]

I'd be happy at 100W, just wondering the ~6000l/h at 5m head.

[Bryan]

That seems rather inflated 1351 Imperial gallons at 15 feet from a 100 watt pump.

[gridley]

I'm certainly no electical enginer, but when choosing my pumps I spoke with an electrical enginer. His recommendation - without hesitation was to go with DC equipment if possible.

Questionable water flow ratings from manufactures aside, a DC pump will use less power to move an equal mount of water compared to an AC pump. DC is more efficient. One advantage of DC is that the speed of the pump can be controlled thereby reducing the power consumed. An AC pump is either on or off - full power use or nothing. A DC pump, if it comes with a speed controller, can be set for a lower speed (lower wattage use) if you do not need the full water flow. I have my Waveline 5000 set at the third of six speeds which provides me with plenty of water flow and uses half the full wattage (approx 20 watts).

[ocean diver]

Can someone post a picture of how these pumps hook into the sump. Thanks

[nrosdal]

Originally Posted by ocean diver

Can someone post a picture of how these pumps hook into the sump. Thanks

here is my dc5000:

[intarsiabox]

Originally Posted by gridley

An AC pump is either on or off - full power use or nothing. A DC pump, if it comes with a speed controller, can be set for a lower speed (lower wattage use) if you do not need the full water flow.

Not really, you can get VFD's (variable frequency drives) to control AC pumps. A lot of commercial/industrial buildings use this method for their pumps and fans to cut down on energy costs. Small VFD's have come down in price a lot but whether the cost of adding one would save you any money in the long run or not I couldn't say, and not at all if you are just going to run the pump at 100% all day long. Not all motors are VFD compatible either so that is something else to confirm. If I were starting from scratch and needed a return pump I would go with a DC model if it was as capable as a similarily priced AC pump in an instant.

[mark]

Originally Posted by intarsiabox

Not really, you can get VFD's (variable frequency drives) to control AC pumps. A lot of commercial/industrial buildings use this method for their pumps and fans to cut down on energy costs. Small VFD's have come down in price a lot but whether the cost of adding one would save you any money in the long run or not I couldn't say, and not at all if you are just going to run the pump at 100% all day long. Not all motors are VFD compatible either so that is something else to confirm. If I were starting from scratch and needed a return pump I would go with a DC model if it was as capable as a similarily priced AC pump in an instant.

Not to forget by restricting outlet of AC pump like the Barracuda, flow and power draw will decrease.

Sphelps, 4m and 4000l/h @ 85w still sounds to good to be true as that 3-4X the efficiency of the Reeflo

[gridley]

Originally Posted by intarsiabox

Not really, you can get VFD's (variable frequency drives) to control AC pumps. A lot of commercial/industrial buildings use this method for their pumps and fans to cut down on energy costs.

Ahaa - I get to learn something new everyday! LOL

Originally Posted by mark

Not to forget by restricting outlet of AC pump like the Barracuda, flow and power draw will decrease.

Sphelps, 4m and 4000l/h @ 85w still sounds to good to be true as that 3-4X the efficiency of the Reeflo

I'm not sure about this - unless the Barracuda operates differently from other pumps, the ability to restrict the outlet does reduce flow, but that isn't linked to power draw - reducing the output/flow typically increases the back pressure on a pump but I'm not sure that it reduces power useage.

[lastlight]

That effect has been measured for sure with the reeflo pumps.

[sphelps]

Originally Posted by gridley

Ahaa - I get to learn something new everyday! LOL



I'm not sure about this - unless the Barracuda operates differently from other pumps, the ability to restrict the outlet does reduce flow, but that isn't linked to power draw - reducing the output/flow typically increases the back pressure on a pump but I'm not sure that it reduces power useage.

Power draw will reduce slightly as head pressure increases, this is typical for most centrifugal style pumps.

You can see in the spec sheet how the power drops.