DC pumps:huge power savings, really?

[mark]

Wondering real world experience with DC pumps in a basement sump application.

The power saving thread had some high head/high flow numbers with what seems really low wattage. Since I'm around 1200gph @ 260W with a Barracuda in the basement would considering switching if true or is it just numbers on the sides of boxes and manufacturer's hype.

[FitoPharmer]

Just looking on the site for these DC pumps the flow chart for their largest model looks kinda funny.
RLSS dc10000

[Madmak]

I run a 10000 to my skimmer (used to be 2 Eheim 1260s) at level 4, a 10000 as my return (used to be a Mag12) at level 4, a 5000 to my reactors, and a Barracuda as my closed loop.

I know they are quieter and use less power (as per my Apex) but I know one of the 10000s wouldn't keep up with the Barracuda, I'm not sure 2 would even keep up but I may test this soon . They are nice pumps but may have a bit of a exaggerated GPH rating.

[Bryan]

As well they advertise 85 watts AFTER the adapter. Don't forget there will be a power loss from the adapter. I am thinking it probably draws 100 watts from the mains.

[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

[sphelps]

Originally Posted by mark

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

Mark, there's obviously a mistake on the website, at 5m head you get zero flow. We discussed this in a previous thread but here's an adjusted pump curve that I believe is more realistic.

[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.