Dry run protection for DC Solar Pump sourcing water from a borehole

[Dream_Renewables]

We are installing solar power irrigation systems for smallholding farmers in Rural Ghana,

We have 12V DC 0.18kW (max 20A) pumps, there only power source will be a voltage varying from 15-20V coming from solar panels.

The boreholes are narrow, therefore is not much room for a float switch,

The max flow is 20 Litres per minute but more typical flows would be 5-10 liters a minute

Can anyone advise on flow or pressure switch solutions (I have done a google but I don't have experience in this area and am not confident myself)

Ideally, there would be no second power source or battery needed, and the solution should be as low-cost as possible. something under £20 per unit for 20 units would be ideal.

(It's a charity project replicating 20 units - so cost is important)

let me know if i missed out any key info

 

[Chuck]

Have you tried asking the pump manufacturer if they have any suggestions?

 

[rpm]

Could you use a manual On/Of switch in a panel or are you looking for something automatic.