# HOW TO: 12V Water pump relay powered by mains power? **URL:** \ **Category:** General Electronics\ **Created:** [September 22, 2024, 9:09am UTC](https://forum.arduino.cc/t/how-to-12v-water-pump-relay-powered-by-mains-power/1303960 "2024-09-22T09:09:16Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![llewy777](https://avatars.discourse-cdn.com/v4/letter/l/e36b37/32.png) [@llewy777](https://forum.arduino.cc/u/llewy777)\ **Post date:** [September 22, 2024, 9:09am UTC](https://forum.arduino.cc/t/how-to-12v-water-pump-relay-powered-by-mains-power/1303960/1 "2024-09-22T09:09:16Z")
Hi there, This is my first Arduino project. I would like to water the pot plant on my balcony for approx 2 min every 12 hrs. power source will be mains supply. Will the bellow system work? do I need to be putting fuses somewhere in here? System Diagram [ProjectWaterPump|690x280](https://forum.arduino.cc/uploads/short-url/3lCtTaxjXGnnDYFznPPcUgqY3aU.png) Buck Converter: > **[DC-DC Adjustable Step-down Module 5A 75W](https://core-electronics.com.au/dc-dc-adjustable-step-down-module-5a-75w.html?gad_source=1&gclid=Cj0KCQjwgL-3BhDnARIsAL6KZ6_9Aeg91ggvcTRmXuqR5EKOFUvfYqyL909ttCp7hOLh7AraXXcVrz0aArWwEALw_wcB)** > > DC-DC Adjustable Step Down Module 5A 75W XL4015 Ardiunio Uno R3: > **[Uno R3](https://core-electronics.com.au/uno-r3.html)** > > The Uno is a microcontroller board based on the ATmega328. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analogue inputs, a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset... Water Pump: [Water Pump 12V Pressure Shower 4.3L/Min – Devanti](https://devanti.com.au/products/12v-portable-water-pressure-shower-pump?srsltid=AfmBOoqxoeDRqlcx26p-2ZEjl_3S5ad__Fca406VR6gQ1w9gMxOn9XVx) ---
**Author:** ![llewy777](https://avatars.discourse-cdn.com/v4/letter/l/e36b37/32.png) [@llewy777](https://forum.arduino.cc/u/llewy777)\ **Post date:** [September 22, 2024, 9:10am UTC](https://forum.arduino.cc/t/how-to-12v-water-pump-relay-powered-by-mains-power/1303960/2 "2024-09-22T09:10:06Z")
Rectifier: > **[12V 1A 2A 3A 4A 5A 6A 10A Power Supply Transformer Adapter For LED Strip 5.5...](https://www.ebay.com.au/itm/164287172168?_skw=12v%2B4a%2Bdc%2Bpower%2Badapter&itmmeta=01J8CEQARVBKF146ZSMRZA3WCR&hash=item2640474e48:g:64kAAOSwXfFhkgcj&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKkkkudnxBVY7PUkTtMT7FXnAJPRL5u9x5qtcyOpX3ER3RTUKWhSuuVq4f%2FiNoL1sDRAjUiNWdclaUHPSkFilHK530fWr4uEW0ahIqmUWtYiNXCUecTiDr1Xim8eyQB4g7BeL851sbSEna8lGUCrqlDnwWQ%2BFcSH%2BzUUz9UXnetfoISkJs6dfM7jPgLkE%2BIS%2BJeAzKbBrPgZx2wDy1YdEQTvQSXPbzSQux7gKMIsxF0etJMbYKkCCbC1aiQN7oGIZ%2FaCeA8iBFysOKpEbrLC5QmOj3OdU440SMhaFx%2Fcz5h%2BBw%3D%3D%7Ctkp%3ABFBMxKzdjsNk)** > > 1 LED Writing Board orany other device Less than 1A power adapters. 1 LED Writing Board orany other device Less than 2A power adapters. 1 LED Writing Board or,any other device Less than 4A power adapters. Relay: > **[5V Single Channel Relay Module 10A](https://core-electronics.com.au/5v-single-channel-relay-module-10a.html)** > > A versatile, compact relay board that can drive up to 10A @28VDC while only drawing approximately 60mA at 5V. ---
**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\ **Post date:** [September 22, 2024, 9:17am UTC](https://forum.arduino.cc/t/how-to-12v-water-pump-relay-powered-by-mains-power/1303960/3 "2024-09-22T09:17:46Z")
@llewy777 > for approx 2 min If you run that pump for 2 minutes you will be pouring 8.6 liters of water on your plant. Maybe a much smaller pump would be better and cheaper. Once you choose a new pump, then you can choose the right power supply. Maybe this: > **[DC Diaphragm Pumps for Arduino Automatic Smart Plant Watering Kit](https://littlebirdelectronics.com.au/products/dc-diaphragm-pumps-for-arduino-automatic-smart-plant-watering-kit?_pos=22&_sid=11ba757fd&_ss=r)** > > This is a 370 DC diaphragm pump for Arduino Automatic Smart Plant Watering Kit 2.1, it could be used on a kettle, stove, water dispenser and other tea products, it can be used in experimental models, regular watering, water-cooled notebook and other... or > **[Amphibious Horizontal Submersible Pump](https://core-electronics.com.au/amphibious-horizontal-submersible-pump.html)** > > Use this amphibious micro submersible pump to build a small fountain, make auto water changer, or DIY plant-watering project! This product is powered by 3-6V and... ---
**Author:** ![2112](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/2112/32/1129664_2.png) [@2112](https://forum.arduino.cc/u/2112)\ **Post date:** [September 22, 2024, 11:41pm UTC](https://forum.arduino.cc/t/how-to-12v-water-pump-relay-powered-by-mains-power/1303960/4 "2024-09-22T23:41:32Z")
That should work. Wire and fuse size is dependent on the length of the 12V circuit. You fuse to protect your wire. The longer the wire the larger the wire. If the distance from the "rectifier" to the pump is 4 meters or less use 16AWG and 10A fuse. ---
**Author:** ![kmin](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/kmin/32/1147370_2.png) [@kmin](https://forum.arduino.cc/u/kmin)\ **Post date:** [September 23, 2024, 9:31am UTC](https://forum.arduino.cc/t/how-to-12v-water-pump-relay-powered-by-mains-power/1303960/5 "2024-09-23T09:31:34Z")
With 4A power supply for sure you don't need to replace that fuse... ---
**Author:** ![2112](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/2112/32/1129664_2.png) [@2112](https://forum.arduino.cc/u/2112)\ **Post date:** [September 23, 2024, 10:56am UTC](https://forum.arduino.cc/t/how-to-12v-water-pump-relay-powered-by-mains-power/1303960/6 "2024-09-23T10:56:30Z")
Oh, I missed the 4A limit on the power source. 4A may not be enough to start the pump. The 6A version MIGHT work depending on wiring. Consider the 10A version. ---
**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\ **Post date:** [March 22, 2025, 10:56am UTC](https://forum.arduino.cc/t/how-to-12v-water-pump-relay-powered-by-mains-power/1303960/7 "2025-03-22T10:56:39Z")
Closed on March 22, 2025, 10:56am UTC This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.