Two DC12000 connected in series for a basement sump

[Boga]

Re: Two DC12000 connectecd in series for a basement sump

You may want to revisit the math on your cost calculations...I believe that 300 watts 24/7 10c/kw comes to around $265 ball park and the iwaki would not be drawing any where near that in actual practice.

Thanks AdInfinitum. You are right. The calculations were for a five-year period and I wrote one year in error. I will change the post, so confusion is minimized. I will look into the other comments.

 

[Boga]

They don't need to be in the water actually

I found the product spec. On page 2, paragraph Important Info, sais that
• In order to ensure product performance, please only operate the pump in water.
• The pump is suitable for indoor use in water only.

Maybe if it is not run at full capacity (speed, head) it could be Okay to run external??

I would think there would be added risk with the two pumps. Just more chance of failure. I have an 1100 gph Little Giant.
In my opinion these pumps have the best pressure and the highest head rating . This pump will easily still achieve 800 gallons per hour at 15 feet imo

Good point. Added as a concern in my review. On the other hand it can be said that if one fails there is still one to keep some flow for backup until a replacement is installed, given that some extra plumbing is installed.

Do you have the Little Giant 3MDQX-SC 1100 gph? If so, it appears that it delivers around 400 gph at 12 ft. Performance charts attached.

...I believe that 300 watts 24/7 10c/kw comes to around $265 ball park and the iwaki would not be drawing any where near that in actual practice.  My Blueline HD 70 (virtually the same pump) will pull about 150-180 watts in the application you used as an example.  The need to change seals etc. is a fair point but submersibles wear too, you just don't notice the gradual loss of efficiency.
...

It appears that HD70 has better flow @ 12ft compared to Iwaki 70rtl. Where did you find the consumption charts? I've tried to find consumption curves for Iwaki and blueline and ... no luck. For Iwaki I used the consumption reported by BRS, which is 336W and estimated for my operating head as ~300W. For DC-12000 I used the max wattage (2x85W), even if it could be less than that.

I think that I have a loss in efficiency with my Mag 18 right now (compared to day one). There could be some obstructions in the tubes, but I also have concerns about the pump.

I am not familiar with the DC pump in question, but in general DC pumps are used in applications when variable speed control, frequent start/stops and/or quiet operation are required.  Generally AC induction motors are far more efficient than DC, other than perhaps some of the newest high end brushless DC motors.  (I'm sure that we have some electricians here that might know better than me)

I think that DC12000 has a brushless DC motor. It looks good in terms of consumption. I have little experience with motors. I think that having a variable speed pump can create an advantage in future reef designs (probably already implemented by some reefers). One example would be to run pump at lower flow during feeding, then pump at maximum to remove suspended nutrients, then maybe slow down little bit for the night, etc.

 

[AdInfinitum]

It appears that HD70 has better flow @ 12ft compared to Iwaki 70rtl. Where did you find the consumption charts? I've tried to find consumption curves for Iwaki and blueline and ... no luck. For Iwaki I used the consumption reported by BRS, which is 336W and estimated for my operating head as ~300W. For DC-12000 I used the max wattage (2x85W), even if it could be less than that.

I had a spec sheet that came with the pump that I can't put my hands on at the moment, but I was looking at about 15' of head and vaguely remember the numbers.  The rating marked on the pump is 290 watts max./150 watts nominal so I guess it was actually 180-200. I was looking at some old design sheets I had made.  The gallons/watt curve on the high pressure pumps really falls off dramatically at the high volume/low head end of the scale, the opposite with high volume pumps.

Interesting cost/benefit question...would love to do some messing around with some pumps and the kill-a-watt meter...

In the "in-between" range like you're looking at it's a closer call but add the potential for couple of extra corners or tee's or feet and it tips the scale.