Solar Troubleshooting & Testing

Fix low solar output fast — with simple checks you can do at home or at camp.

If your solar setup isn’t charging like it used to, the cause is usually one of these: shade, heat, loose connections, incorrect controller settings, cable losses, or a battery that’s already full.

This page gives you a clear step-by-step process to identify what’s going on — and when it’s time to contact support.

Start here: the 60-second quick check

Before you pull anything apart, check these first:

  1. Is there any shade?
    Even partial shade from roof racks, aerials, branches, or a small shadow can heavily reduce output.

  2. What time of day is it?
    Peak output is usually late morning to early afternoon in clear sun.

  3. Is the battery near full?
    If your battery is almost full, your controller will reduce charging power (normal).

  4. What does your controller show?
    Take a photo of these readings:

  • PV (solar) Volts (V)

  • PV Amps (A)

  • PV Watts (W)

  • Battery Volts (V) + charging stage (Bulk/Absorption/Float)

✅ If you can provide those numbers, diagnosing becomes much faster.

Troubleshooting menu (pick what matches your issue)

1) “My solar is showing low watts”

Most common causes:

  • Panel is hot (heat reduces output)

  • Sun angle isn’t ideal (panel flat on roof)

  • Voltage drop from long/thin cable runs

  • Controller limitation (PWM vs MPPT)

  • Partial shading or cell damage

Do this next:
Follow our full guide:
https://help-centre.starpoweradvancesolartechnology.com/support/solutions/articles/51000502643-comprehensive-solar-panel-troubleshooting-guide

2) “My controller shows PV voltage but 0 amps / 0 watts”

This is usually a connection or settings issue.

Check:

  • MC4 connectors fully seated (click locked)

  • No adaptor/branch connector failure

  • Correct polarity (positive to positive, negative to negative)

  • Controller PV input within rated voltage range

  • Battery connected first (some controllers need battery connected before PV)

Next step: run a basic panel test (below).

3) “My solar was working, now it’s intermittent”

Common causes:

  • Loose MC4 connection

  • Water ingress / corrosion in connectors

  • Cable break near strain points

  • Controller thermal throttling (overheat)

  • Portable blankets with worn hinge/lead wiring

Check:

  • Wiggle test connectors (with system safely isolated)

  • Inspect MC4s for water, discoloration, burning marks

  • Check cable for cuts / flattened areas (door seals, storage lids)

4) “My panel looks damaged (bubbling/yellowing/delamination)”

For flexible panels, these symptoms can indicate heat stress or delamination.

See our guide:
https://help-centre.starpoweradvancesolartechnology.com/support/solutions/articles/51000502811-flex-panel-delamination-bubbling-yellowing-causes-remedies

Step-by-step: How to test if your solar panel is working

This is the most accurate way to confirm panel health.

✅ Use this guide (recommended):
https://help-centre.starpoweradvancesolartechnology.com/support/solutions/articles/51000494740-how-to-test-if-your-solar-panel-is-working-correctly-step-by-step-guide-

What you’ll typically test

  • Voc (Open Circuit Voltage)

  • Isc (Short Circuit Current) (only if you’re comfortable and doing it safely)

  • Compare your results to the panel label/specs

Tip: Test in clear sun, panel facing the sun, and note the time.

Common reasons solar “looks low” even when it’s normal

Heat (most common)

Solar panels lose efficiency as they get hot — roof installs run hotter than portable panels.

Battery already full

As the battery reaches full charge, the controller reduces current (watts drop).

PWM controller with higher-voltage panels

PWM can reduce usable power compared to MPPT, especially with certain panel voltage specs.

Shade + bypass diodes

A small shadow can drop output a lot, even if the rest of the panel is sunny.

When to contact support (and what to send)

If you’ve tested in clear sun and output still seems abnormally low, contact us with:

  • Photos of the panel front + back label

  • Photos of installation and wiring path

  • Controller make/model

  • Controller screen photo showing:

    • PV Volts, PV Amps, PV Watts

    • Battery Volts and charge stage

  • Your location + time of test + weather conditions

Support & Contact:
https://help-centre.starpoweradvancesolartechnology.com/support/solutions/articles/51000501187-support-contact

Helpful learning links

FAQ

Why does my solar produce less than the label wattage?

Most panels are rated under STC lab conditions. Real-world output changes with heat, sun angle, controller type, and wiring losses.

My controller shows volts but no amps — is the panel dead?

Usually not. It’s often a connection, polarity, controller setup, or a blown fuse/disconnect issue. Run the step-by-step test above.

Can a small shadow really drop output that much?

Yes. Shade can affect an entire section of the panel and reduce total power significantly.