Accurate Solar Sizing

How to Troubleshoot a Solar System That Stops Charging

ByGLOBALNET ICT

When your solar system suddenly stops charging, it can be frustrating — especially if you rely on it for your daily power needs. The good news is that most charging problems come from simple issues that you can diagnose and fix quickly.

In this guide, you’ll learn the step-by-step method to troubleshoot any solar system that stops charging, whether you’re using lead-acid, lithium batteries, MPPT/PWM controllers, or hybrid inverters.

Let’s get started.

Solar Systems

1. Check If Sunlight Is Reaching Your Panels

Solar panels need direct sunlight. Even minor shading can stop charging completely.

Common shading issues:

  • Water tank shadow
  • Roof edges
  • Trees and branches
  • Satellite dishes
  • Neighbor’s building

✔ How to fix it:

  • Remove shading objects where possible
  • Trim overgrown trees
  • Adjust panel orientation

Even 10% shade can reduce charging by up to 40%.

2. Inspect the Solar Panels for Dirt or Debris

Nigeria’s weather — dust, harmattan, and bird droppings — reduces panel efficiency drastically.

A dirty panel = weak or no charging.

✔ How to fix it:

  • Clean panels with a soft cloth, water, and mild soap
  • Clean weekly during harmattan
  • Avoid scrubbing with abrasive tools

Regular cleaning can restore 20–40% lost charging power.

3. Check Solar Panel Connections

Loose, burnt, or corroded connections will interrupt charging.

✔ What to inspect:

  • Panel-to-panel connectors (MC4)
  • Junction box
  • Combiner box
  • Wiring joints

✔ How to fix it:

  • Ensure connectors are firmly locked
  • Replace burnt connectors immediately
  • Tighten loose wires

If your system uses series connections, one loose wire will cut off charging entirely.

4. Check the Charge Controller (MPPT or PWM)

Your charge controller is the “brain” regulating solar charging.
If it fails, battery charging stops completely.

✔ What to look for:

  • Is the controller ON?
  • Is it showing solar input voltage?
  • Is it showing “charging” mode?

✔ Fix options:

  • Restart the controller
  • Check if its fuse is blown
  • Check for error codes
  • Confirm correct battery type selection

If the controller does not display PV voltage, the issue is coming from the panels or wiring.

5. Check Inverter/Controller Settings

Wrong configuration can stop charging.

✔ Ensure these settings are correct:

  • Battery type: Lithium / AGM / Flooded
  • Max charging current: Not set too low
  • PV input voltage limit: Not exceeded
  • Bulk and float voltage settings correct

✔ For hybrid inverters:

Make sure solar mode is not disabled in the settings.

6. Check the Battery Voltage

Sometimes the system is charging, but the battery is too low to show improvement.

✔ Signs of low battery issues:

  • Battery voltage below 10.5V (for 12V systems)
  • System refusing to accept charge
  • Inverter shutting down

✔ How to fix it:

  • Charge battery with generator or grid for 10–20 minutes
  • Then reconnect solar — it will resume charging

Lithium batteries may enter protection mode when too low.

7. Look for Faulty Fuses or MCBs

Blown fuses stop solar input instantly.

✔ Check:

  • Solar input fuse
  • Combiner box fuses
  • DC breaker (MCB) between panel and controller

✔ Fix:

  • Replace blown fuses with same rating
  • Reset tripped MCBs

8. Test the Solar Panels With a Multimeter

If everything looks fine but charging is still not happening, test panel output.

✔ Steps:

  • Set multimeter to DC voltage
  • Measure at panel terminals
  • A 12V panel should read 18–22V in sunlight
  • A 24V panel should read 36–44V

✔ If voltage is low:

  • Panel may be damaged
  • Shading issue
  • Faulty bypass diode
  • Water inside the panel

9. Check for Undersized or Long Cable Runs

Thin wires cause voltage drop.
The panel may be producing power but not enough voltage reaches the controller.

✔ Recommended sizes:

  • 4mm²–6mm² for panel wiring
  • 10mm²–16mm² from battery to inverter

If cables are too long or thin → charging becomes weak or stops entirely.

10. Confirm the Solar Panels Are Not Faulty

Solar panels rarely fail, but it happens.

✔ Panel failure signs:

  • Zero voltage reading
  • Burn marks behind panel
  • Hot-spot damage
  • Delaminated glass
  • Water leakage inside panel

Replace damaged panels immediately.

⭐ Bonus: Use the Globisun App for Error Codes and Troubleshooting

The Globisun Solar App helps users:

  • Identify solar charging issues
  • Check battery & inverter error codes
  • Calculate correct panel sizes
  • Know if battery is too small
  • Optimize solar performance

This makes troubleshooting faster and more accurate.

⭐ Final Thoughts

When your solar stops charging, the issue usually comes from:

  • Dirty panels
  • Shading
  • Loose connectors
  • Wrong settings
  • Faulty charge controller
  • Blown fuses
  • Low battery voltage
  • Bad wiring

Follow this step-by-step guide and you’ll quickly find and fix the problem.

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