Why is the Low Power Light active on the Solar Pump Controller?

 

1. Make Sure the Pump is Running at Full Speed

• Look at the Speed Control dial located on the centre right of the controller’s circuit board
• Turn it all the way clockwise (up to 10) to maximum speed.
• This ensures you get full power output during testing.

 

2. Check Sunlight Conditions:

• The pump controller relies on sunlight for power unless connected to a battery or mains power pack.
• During early morning, late afternoon, or heavy cloud cover, there may not be enough solar power to activate the unit.
• Wait until full daylight (midday) and recheck.

 

3. Check for Panel Faults or Disconnects:

• Make sure the pump controller and pump are not operating during this check. Check each panel’s MC4 connectors by unplugging them from each other and then plugging them back into each other. This connection needs to be firm and complete to allow power flow while under load.
• Use MC4 tester or multimeter to isolate faults between solar panels if available.
• If the panels are far from the pump controller, you may experience voltage drop.
• If voltage is good at the solar panels but low at the pump controller, check the cable size is correct and in good condition.

 

4. Inspect Solar Wiring Connections:

• Open the controller carefully.
• With the incoming power switched off, check that the solar panel wires are securely connected to P+ and P- terminals.
• Check for loose wires, burnt connections, and corrosion on the P+ and P- terminals.
• Check for damage to the power input cables.

 

5. Test the Solar Panel Voltage:
With the incoming power turned on, use a multimeter to check the voltage at the P+ and P- terminals:

• Check that the polarity of the incoming solar power is correct by placing the red (positive) probe on P+ and the black (negative) probe on P-. If the voltage is in negative numbers, the polarity is incorrect, and the wires need to swap terminals. Turn incoming power off before swapping the wires to the other terminals.
• 24V pump systems should show 35V–55V open circuit voltage (Voc)

• 48V pump systems should show 65V–109V (Voc)
• 72V pump systems should show 80V–140V (Voc)
  If the voltage is in this range but there are no lights, the issue may be inside the controller.

 

6. Failed or failing bearings:

Failed or failing bearings can affect the rotation of the pump motor and cause it to rotate slower than normal.

• Remove the pump from the water or disconnect the water inlet pipe and separate the motor from the pump to check:
  • That the motor shaft can turn freely with a clunking sensation as it is turned. The clunking sensation is the motor shaft’s magnets moving between the windings and is normal.
  • That the motor shaft does not wobble side to side.

 

7. Impeller Wear and Rotational Speed Restriction

Sometimes, a failing rotor and stator can become tight and cause the pump motor to rotate at a slower speed. This can also be caused by debris such as grasses or reads.

• Inspect the inlet screen for grass, reads, or plastic wrapping and ensure the pump is not drawing in mud or grit from the water source.

 

7a. Submersible Screw/Helical Rotor Pumps (e.g. bore pumps):

These pumps contain a rotor (metal screw) and a stator (rubber sleeve) that wear out and can become tight over time.

• The rotor and stator (impeller) should be replaced every 1–2 years depending on your local water conditions (e.g. grit or mineral content).
• Remove the pump and check:
  • The rotor can turn freely inside the stator.
  • If it has become tight, swollen or the rubber has hardened, it can reduce the running speed of the pump.

For instructions, refer to the "How to Replace an Impeller" section of the user manual.

 

7b. Centrifugal Multistage Pumps

These pumps have multiple spinning impellers and are sensitive to clogging which can affect their rotation.

• Check the inlet screen and impellers for blockages (grass, reads, algae, etc.).
• Running the pump backwards can help clean out the impellers if they are not badly clogged.
  • Run the pump backwards for 5–10 minutes.
  • Switch back to forward for 5–10 minutes.
  • Then reverse again one more time.

To reverse the pump’s running direction:

1. Turn the solar isolator off.
2. Open the controller and take a photo of the pump’s power cable wiring.
3. Swap the wires on the V and W terminals with each other.
4. Turn the solar isolator on.

Note: Be cautious and contact Commodore Australia if you are unsure of this process.

 

If the impellers remain clogged, you may need to disassemble and clean the pump.

• This involves removing and reassembling multiple internal parts in the correct order.

• Contact Commodore Australia on 1300 669 256 for detailed guidance.

 

7c. Single impeller Centrifugal Pumps

These pumps have a single spinning impeller that can be sensitive to clogging. To check the impeller, you will need to disassemble the pump to access the impeller for cleaning.

Contact Commodore Australia’s Technical Support team for further assistance.

Phone 1300 669 256 or email support@commodoreaustralia.com.au