Want a variable-speed water pump for a bath shower-head, what do I need?

Basically I want to make a shower head for the bath that pumps water from the bath, so I don’t have to worry about wasting water. Thing is, I don’t want to just switch on a water pump and have it either full on or full off, I’d like to be able to vary the power.

I can see there are some brushed pumps, which would obviously work with a motor driver, but it looks like there are a lot of cheap & easy to acquire brushless pumps out there as well, like this one. Given that they run on just two wires, is there any way to control the speed of these brushless pumps?

There’s also this more expensive pump, but it runs on just two wires and says it features a hall-effect sensor, so I assume that means it’s brushless too. Any way to control the speed of this one?

Also I want the pump to be powerful enough to supply a decent shower. I just don’t have any experience with water pumps - is 100L/hr good enough? 500L/hr? I just don’t know. The brushed ones seem a bit weaker, and I’d rather go with brushless anyway just for efficiency & service life.

Am I on the right track here? Any suggestions?

Hi Michael,

I don’t need to tell you that having power running into water you plan to stand in is potentially dangerous. That said…

I think you might find that most of our pumps won’t have a high enough flow rate to shower with. A typical shower uses about 15 Liters per Minute. That’s 900 LPH. You could vary the speed of a permanent magnet DC motor by reducing the voltage provided, but I these are sealed units and I’m not sure if it’s just a motor or if there is a controller circuit in there as well.

You can vary the speed of a brushless motor, but it needs to be connected to a controller that allows that. Again, these units are sealed and it’s likely there is a speed controller built in that doesn’t have that capability.

You could try this pump: https://core-electronics.com.au/liquid-pump-350gph-12v.html
I think the flow rate might be a little high though.

What you should look into is a constant pressure pump, with standard shower valve hardware.

I hope that helps! Let us know how it goes!

Thanks Stephen, I didn’t see the notification email, otherwise I would have responded a lot sooner!

I’m aware of the potential risks, but as long as I only run 12v power then I assume there’s no real danger. I think it takes a lot more than that to hurt you.

As for the type of pump, I guess I’ll just have to experiment to figure out what I need. I’m starting with the cheapest ebay stuff I can find and I’ll work my way up from there.

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