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How to connect 12v water pump to the 240v wall socket Answered

Hi there
I really hope someone can help.
I want to install a campervan tap setup in my office (tu cut a long story short, I need the sink and running water and the building is too old and no plumber will work there for little money) and got a 12v water pump which I indent do connect to a tap and feed from a 20L water tank. 
This is the pump: http://www.trademe.co.nz/motors/boats-marine/parts-accessories/pumps-tanks/auction-1195429887.htm
I got these details:
Volts: 12V Nom. (9-14.4V)
Amps: 3MAX (3.5A fuse required) 

My question is: Can I hook it up to a 12V 5A power adapter to it and simply plug it to the wall?
This is the adapter I found: https://www.aliexpress.com/item/Power-Adapter-Supply-For-Led-Flexible-Tape-Light-AC110-220V-to-DC12V-1A-2A-3A-4A/32658402593.html?spm=2114.13010608.0.0.k9Mw96

I really hope someone can help as I'm useless with this stuff 

11 Replies

Josehf MurchisonBest Answer (author)2016-11-09

Oh Yea just use the adapter it should be fine with amps to spare. The pump will only use what it needs.

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RacineO (author)Josehf Murchison2016-11-12

Thanks a lot, I'll try post a photo of my project. I need it to look neat and got a stainless tap and sink to go with it. This is actually for my office. I didn't really understand most of what everybody else said considering I'm quite thick with electricity but in New Zealand Electricians and Plumbers are super expensive.

Thanks again

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Josehf Murchison (author)RacineO2016-11-12

When I checked the specks of your pump on the net I found a couple pages where they sold the pump with that adapter so it should be fine.

The others were talking about the starting current of the pump, if the pump stalls at startup you might need a capacitor.

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iceng (author)Josehf Murchison2016-11-09


The pump must be powered from a 12 volt supply.. After that, the pump will draw the current (Amps) that the pump motor needs depending on how much energy it needs to push water how_high => (pressure) and flow rate of water..

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Downunder35m (author)iceng2016-11-09

But from previous experience with switch mode power supplies I would like to make one suggestion:
Add one ore two reall big electrolytic capacitors paralell to the pump and power supply.
I noticed that switch mode power supplies often struggle with inductive loads turning on at full power.
This can lead to "stuttering" of the motor.
You hear or see it kicking in hard but turning off immediatly, this can go on for a few seconds or even minutes until the powr supply finally gives up trying and shuts down until power cycled.
A capacitor (bank) of 20000 - 50000µF in elecrolytic capacitors will make sure the inrush current of the motor won't affect the power supply too much.
If you have hard rubbish collections near you then old audio amplifiers are a good source to get some decent capacitors for free.
It might pay off though to add a current limiting resistor of suitable size if you don't intent to keep the power supply on 24/7.
Otherwise every time you switch the system on the empty capacitors would basically create a dead short for the power supply.

To prevent hassle and cost check if your power supply is good enough to power the pump directly when required.
If you see stuttering happen check the above and cosider some decent capacitor(s) added to the mix ;)

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Start up surge, 5 amps should be enough to cover that but if it is not 470 uF 25 volt electrolytic capacitor should be more than enough.

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Nematic! (author)2016-11-27
rickharris (author)2016-11-10

Wo9uld it nt be easier to install a pump type tap that is often used in mobile homes rather then get involved with electricity?

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That is the pump used in mobile homes with a 35 psi auto shutoff.

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Jack A Lopez (author)rickharris2016-11-10

If the location has gravity, a siphon can be used for dispensing water from a bottle. Brent's classic, Golden Book of Chemistry, (Golden Press, New York, NY, 1960) has some words, and pictures, describing this, on pages 10 and 11.

And of course this book can be found for free, various places, at the time of this writing,


Of course the shelf to support a 20 kg water bottle needs to be sturdy, and it will take some muscle to lift it up and set it there.

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