Solar Pump Inverter Selection Guide

What is the solar pump inverter?

It is an off-grid or stand-alone inverter that converts DC power getting from solar panels (photovoltaic array) to AC power to supply pumping system.
With solar radiation changes, solar panels output DC power will change, so the solar inverter play an important role in receiving such variable power and producing maximum AC power to the pump, also it adjusts output frequency in real time so can run the pumping system at max efficiency.
Before deciding on the size of solar pump inverter for pump and solar panels, you need to confirm one thing first. What needs to be checked is the pump motor itself, whether it is compatible and suitable for use with the inverter.

How to choose the rated power of the solar pump inverter?

1. Inverter power capacity can be indicated based on AC pump rated current or power capacity, the common rule is 1.4 larger than AC pump rated current. So, for 5A rated current pump, the inverter output current should be 5A * 1.4A = 7A.
   Also, you can indicate solar panels total power capacity based on inverter power capacity. It equals inverter power x 1.4 (same rule).
   
   
2. Solar pump inverter DC input voltage range. You need to know 2 things to indicate it as following:
      1. Solar module (panel) max rated voltage which called Vmpp, and this can be easily gotten from Solar panel data sheet or name plate,
      2. Number of modules per string.
   By knowing A, B you can get max voltage that can be received from the solar array, then choose the inverter input voltage range so can cover this crucial value.
   For example, if we have 6000W solar array, and the module power is 400W with Vmpp = 36V.
   This means that total number of modules per array = 6800/400 = 17.
   If we shall make the array in 1 string, then voltage per string (Vmmp) will be 17 * 36 = 612V.
   So Inverter DC input range upper limit should be 650 or 700, ... , etc.

Solar pumping inverter amazing features

• It runs and stopped automatically according to sun radiation intensity (DC power), so can solve instability issue of solar energy.
• It tracks the max power point of solar panel, so can provide the max AC power to the pump (99% efficiency).
• Its input can be regular power grid and solar power, so we can switch between them or even run the inverter at the night with regular power grid.
• Has numbers of internal protections (over current, short circuit, lightening, overvoltage, undervoltage, ..., etc.) to protect the system.