DC Pump is Better than AC Pump in Solar Pumping System

The solar water pump is the heart of solar pumping system, so selecting the good reliable pump is a crucial choice in building your efficient system.
Mainly in the market there are 2 types of solar pumps: AC pump and DC pump.
DC solar pump uses DC motor which works based on direct current supply (such as solar panel or battery), so it does not need an inverter.
While AC solar pumps uses AC motor which powered via solar pump inverter that converting DC getting from solar panels to AC.

Then which one is better, AC pump or DC pump?

Actually, we usually use DC pump in low power capacity system up to 5kW, but there are some factors to mind when selecting one of them, as each has advantages and disadvantages as well.

• Price
  While DC pump is more efficient than AC pump and required less solar panels to operate, it is difficult to maintain in remote areas as it needs specialized service centers, and you will not be able to run for emergency in night time, also its price is higher than AC pump.
  For the price, AC solar pump will be less expensive of course.
• Service life
  For Life span, DC solar pump has longer life time as it uses motor coils manufactured from pure copper, while AC solar pump uses motor coils manufactured from aluminum/copper to achieve competitive price.
• Noise
  For noise, DC pump is less noisy, it is totally quite because it uses internal BLDC motor with high manufacturing technology while AC pump uses old motor technology, moreover the noisy sound of AC pump will increase with time usage increase.

Consequently, now it is clear that using DC pump is much better than AC pump.

DC Solar pumping system component

Mainly the DC solar pumping system consists of solar panels, controller and the DC pump. The most important part is the DC controller which has 4 important rules:

1. Regulate DC input voltage to hit max power point tracking (MPPT), so running the pump at highest efficiency.
2. Automatically start and stop the pump.
3. Soft starting the pump.
4. Provide various kinds of protections like overcurrent, short circuit, over voltage, under voltage and over temperature.

The DC controller also has a display to show real time measurements for pump power, voltage, consumed current and speed.

How to choose the DC Solar Pump?

This can be easily done by indicating required max water flow for your application in cubic meter per hour, and the max pump head in meter.
The DC solar water pump head can be gotten from knowing the distance between the pump and well & the distance between well and water tank as shown in this picture:

h1 is the head above water (water to tank), h2 is the head under water (pump to water), d is the horizontal distance between tank and pump.
So, the actual pump head: H=h1+h2+d/10.
For example:
h1=50m, h2=30m, d=20m.
Then H=50+30+(20/10)=82m.
The actual pump head is 82m.
According to the estimated flow and head, refer to the performance curves and select the solar water pump with the appropriate flow and head. Then confirm which working voltage 12V/24V/36V/48V/72V/110V is suitable for the solar pumping system. Or send all your requirements to our customer service, and then we will help you to choose the right pump.