Help with solar water pump controller

Thread Starter

nickmms

Joined Jan 2, 2014
40
What I would like to do is switch a 240V pump on when our solar pump does not deliver enough pressure. (Attached schematic)
I am trying to use a solar panel to try to calibrate when there is sun to run the solar pump to turn a 12 V NC relay on approx. 30mA coil.
To get the approximate pull in current I wanted, I added a resistor across the coil and increased the load to about 100mA. So, the relay turns on when there is about the right pressure from the solar pump. I guess if the relay dropout current was about the same as the pull in current then it would work
I can sort of get it to work when it detects enough current to turn the relay on, however, the drop out current/Voltage is not acceptable.
Is there a way I can increase the dropout of the coil this with a transistor, or do I have to use a current measuring circuit or some other way?
I was thinking of using a LM555 timer say set for 5 mins to run so the other relays don't keep flipping on overcast days.. I think this part I can do
Thank You
The solar panel I am currently using is 20Watt 18V but i am getting another one of 5 watts which hopefully should be enough for detection
I think the solar pump controller probably has some relays I could use to determine when the pump is pumping. However, the pump is about 500 from the house with trees etc so wireless maybe is out of the question, I think.
I have very little electronics know how but I can make up circuits.
 

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MrChips

Joined Oct 2, 2009
30,488
Hello Niick, “Help with” what?

Give us a hint as to what your thread is all about. Imagine if every thread title was “Help”.

A better title would be “Help with solar water pump controller”.
 

Thread Starter

nickmms

Joined Jan 2, 2014
40
Hello Niick, “Help with” what?

Give us a hint as to what your thread is all about. Imagine if every thread title was “Help”.

A better title would be “Help with solar water pump controller”.
thank you MrChips..not sure where the rest went when I posted
 
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