Pump Start Relay for 12V pump.

I have a 12V automatic water system pump connected to a marine battery that is charged by a solar panel. The pump is used to get water from a cistern to supply water to the irrigation (note the cistern has a float that maintains a water level so that it is never dry -- if it gets too low, the float allows city water into the cistern to maintain a 10% level in the tank). This is all controlled by a regular irrigation timing system that has an option for a pump start relay.

I want to attach a pump start relay to the system, but the ones I've seen are for 24V sprinkler systems and my pump is 12V.

Is there a 12V pump start relay or a way that I can set this up to use a pump start relay with my 12V pump?

 

Welcome to the forums.

Ok....what is that option ?
Is it a switch contact that closes or is it a voltage output ?

With that information and the current draw of the motor..... we can get you fixed up.

 

As a worst case I think you could use an automotive solenoid. The coil is 12 volt and the contacts are designed to handle a very high current load and better still they happen to be pretty inexpensive.

 

The amp draw on the pump is 4.4 @10psi and has a max psi of 50. I believe that the sprinkler timer pump relay option is a switch contact -- the instructions say that it "allows a pump start relay to operate whenever a station is on." So it activates the pump from the timer. There is a "Pump" terminal on the timer -- you connect one wire from the relay to the Pump terminal and the other to the Common terminal.

The automotive solenoid might be a viable option if nothing else is available.

 

The automotive solenoid is a good heavy duty relay but it's not rated for continous duty.

A 12 volt relay like what is in the link below is exactly what you need. Tyco is one brand, Bosch is another. These relays can be purchased almost anywhere online. Any car stereo/mobile electronics store will have them. Many autoparts stores carry them. Most people recognize them as a driving lights relay. Same difference.

They use .250 crimp-on flat slides......or they have a wiring plug that comes with it.

12 volt relay

 

There are master solenoids used in older cars and tractors & golf carts that are continuous and basically connect the battery whenever the key is turned. You are correct that starting solenoids are only for intermittent duty.