I am looking for pumps suitable for pool filtering that can run on DC current.

I know about one company (Lorentz) that sells these pumps but the price seems abusive if compared to an AC pump of similar capacity.

What I need is a pump that can handle a volume of about 15m3/h at 1.5 bar(loses from the filter in the pool).

Do you know where I could get such a pump? Or should I mount a DC motor myself? 

Please explain why you are limited to inefficient maintenance needing DC for this application.

Brushless DC motors are much more expensive to produce and are certainly specialty devices => premium prices.

Can you get more out-of-the-box on this?  I would look at gravity filtering. Have the filter be tall.  Have the filtration provided by the water gravity flowing back down to the pool.  Then any water at any flow that makes it to the top of the filter container WILL be filtered on the way back down to the pool.

With that type of setup you could then use the most efficient pump you can find to reach supply only the head to the top of the filter.  Then you could use something like a diaphragm pump that still pumps efficiently at whatever speed the system can deliver.  Rather than a centrifugal that at low power is forced to spin slowly and ends up producing just about nothing.


Anyway, just a thought.

If you haven't messed with VFDs it would probably be too risky for you to go that route.  I think you can program some of them to run only at the power rating that keeps their DC link at some minimum voltage but I have not personally tried that.

Just replacing an AC motor with a DC motor is not as straight forward as you might think. The two types of motors have different characteristics.

A brushless DC motor is really a fully synchronous AC motor and requires a sophisticated controller to run it.  A standard DC motor has brushes and only about 70% efficiency which when coupled to a pump that is only 70% efficient really starts to suck as you are using expensive solar.

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