If a solar street light is not working, start with the basics in order: confirm it’s in ON/Normal mode (not OFF/TEST) and that any timer/remote schedule is correct. Next, check the solar panel for dirt or shading, then inspect wiring/connectors for looseness, corrosion, or damage. Look for water ingress (fog under the lens, rust, green corrosion) and test the day/night sensor by covering it. If the light only fails after 2–4 cloudy or rainy days, the most common cause is insufficient autonomy (battery/panel sizing or an aggressive dimming profile), not a single “bad lamp.”
When a solar light suddenly stops working, it’s annoying. You type “why is my solar light not working” into Google and see a hundred different answers. Sometimes it’s just dust on the panel. Sometimes it’s an old battery. And sometimes—if you’re dealing with a whole road of solar street lights—the real problem is system sizing or configuration, not the lamp itself.
I’ve been working with solar street lighting and infrastructure projects in Africa for more than 15 years. I’ve seen everything from 10 USD garden lights dying after the first rainy season, to 12 m poles still running strong after 8+ years because the system was designed correctly from day one.
This guide is written for two types of people:
- Homeowners with small garden / wall solar lights
- Project engineers, EPCs and municipalities managing 6–12 m solar street lights
I’ll mark commercial notes as Pro Tip (Commercial) so you don’t waste time on the wrong checklist.
Start Here: Garden Light or Street Light Project?
If you have a small garden/wall light using AA/AAA batteries, follow the homeowner steps in each section.
If you manage a project (6–12 m poles, LiFePO₄ packs, MPPT controller, possible 4G/5G/IoT control), focus on the Pro Tip (Commercial) notes and the project-level diagnosis section.
Solar Light Not Working: Symptom → Likely Cause Table
| Symptom (On Site) | Most Likely Cause | Quick Check | Fastest Fix |
|---|---|---|---|
| Never turns on at night | Wrong mode / schedule / sensor issue | Confirm ON/TEST, timer profile; cover sensor | Correct settings / reset controller |
| Works only 1–3 hours | Weak battery or undersized system | Compare dawn voltage + after full sun | Replace pack OR resize / re-profile |
| Fails after 2–4 cloudy/rainy days | Autonomy too low / charging limited | Look for seasonal pattern | Resize battery/panel or adjust dimming |
| Flickers / intermittent | Loose connector / corrosion | Tap test + inspect connectors | Re-crimp, waterproof connector, add drip loop |
| Turns on in daytime | Sensor interference / wrong placement | Check nearby lights hitting sensor | Reposition sensor / adjust settings |
| Many poles fail in one section | Design/config/shading or wiring batch | Compare failures by road segment | Fix batch issue / re-configure / retrofit |
How Do Solar Lights Work (Simple Terms)
A solar light is a tiny power plant: panel charges battery, battery powers LED, and the controller decides when to turn it on/off and how to protect it.
Key parts:
- Solar panel — converts sunlight into DC electricity
- Battery — stores energy (AA/AAA Ni-MH for small lights; LiFePO₄ or GEL/AGM for street lights)
- Controller / driver — manages charging, protects battery, controls on/off
- LED module — uses the stored energy
- Sensors (optional) — light sensor and motion sensor
If any part fails (or the system is undersized), the light can dim early, behave oddly, or stop working.
Check 1: Confirm the Light Is Actually Turned On
Many solar lights ship in OFF or TEST mode.
Look for:
- A physical ON/OFF button (sometimes under a rubber cover)
- A mode button that cycles brightness or timing profiles
Homeowners:
- Press and hold power button for 3–5 seconds
- Cover the panel to simulate night
- Cycle modes (some modes run only a short time)
Pro Tip (Commercial):
Engineering-grade street lights may have an internal DIP switch/jumper (test vs normal), an IR remote, or an on/off schedule inside a 4G/5G/IoT platform.
Before sending a team at night, confirm:
- schedule (on/off times + dimming curve)
- group/scene configuration
- time zone settings
Many “dead lights” in projects are actually wrong settings, not hardware faults.
Check 2: Panel Dirty or Shaded
Dirt and droppings reduce charging. Partial shade can reduce output enough to cause early shutoff.
Check:
- dust/mud/bird droppings layer
- cracks or broken glass
- new shade from trees/buildings/billboards
- loose connector at the panel
What to do:
- Clean gently with a soft cloth/sponge + mild soapy water
- Avoid harsh chemicals or abrasives
Pro Tip (Commercial):
For road projects, define a panel cleaning routine:
- every 3–6 months for normal roads
- more frequently for industrial/dusty zones
Check 3: Recent Weather and Autonomy
If the light fails only after several cloudy/rainy days, it may not be broken. It may be undersized.
Consumer lights:
- often designed around “sunny day → one night”
- several cloudy days can drain the battery and it needs strong sun to recover
Pro Tip (Commercial):
If your project lights always die after 2–3 rainy days every year, this points to a system design mismatch:
- insufficient battery capacity (autonomy too low)
- insufficient panel size for seasonal charging
- overly aggressive power profile (100% brightness all night)
At that point, you must resize (panel/battery) or re-profile (dimming curve). You can’t “repair” missing autonomy with tape and hope.
Download a Field Checklist for Your Team: Get the PDF checklist
Check 4: Battery Dead or Too Weak
Batteries are the number one failure point.
Homeowners (AA/AAA garden lights):
- symptoms: very dim, or only 1–2 hours runtime
- actions: open battery compartment, check corrosion, replace with Ni-MH rechargeable (not alkaline)
Pro Tip (Commercial):
Street lights often use LiFePO₄ packs (3.2 V / 12.8 V) or GEL/AGM in older systems.
Look for patterns:
- many poles dim earlier than before
- whole sections go off after midnight
- low voltage readings across multiple poles
If many poles installed at the same time show the same weakness, it’s usually pack quality, cycle life, or sizing assumptions, not random luck.
Check 5: Water Damage and Sealing
Signs:
- fog/condensation under lens
- rusted screws/brackets
- green corrosion on terminals/PCB
- water stains inside housing
Homeowners:
Drying may help short-term, but corrosion keeps growing. Replacement is often more realistic.
Pro Tip (Commercial):
For road/coastal environments, insist on proper sealing and waterproof cable glands/connectors.
Also check installation errors:
- unused holes left open
- glands not tightened
- junction boxes left open after testing
Check 6: Loose or Corroded Connections
If the light flickers or reacts when you tap it, suspect a connection problem.
Check:
- plug connectors that pull out too easily
- crimp lugs that rotate/slip
- broken wires at hinges (folding panels)
- burn marks/discoloration on terminals
Pro Tip (Commercial):
Use tinned copper lugs + double crimp, adhesive heat-shrink, waterproof connectors, and drip loops to stop water tracking into joints.
Check 7: Sensors and Photocells
If sensors fail or are interfered, the light may stay off, turn on in daytime, or behave erratically.
Quick checks:
- cover the sensor (does it turn on?)
- clean dust/spider webs/paint
- check nearby security lights shining onto the sensor at night
Pro Tip (Commercial):
Verify controller timing / IoT schedule settings (including time zone) if behavior looks like a “clock problem.”
Check 8: Multimeter Tests (Panel and Battery)
A multimeter can quickly tell you whether the panel is producing voltage and whether the battery is holding usable voltage.
Safety note: For project systems, follow your site safety procedures.
Test the panel:
- set multimeter to DC volts
- in strong sun, measure across panel terminals
- near-zero volts often means damaged panel, broken wire, or bad connector
Test the battery:
Best practice is to measure:
- just before sunrise (end of discharge)
- after a full sunny day (end of charge)
Pro Tip (Commercial):
Voltage thresholds depend on chemistry, BMS, and controller settings. Use the pack label/spec as your reference. If you’re unsure, send a photo of the battery/controller label.
Check 9: Repair vs Replace vs Retrofit
Homeowners:
If cleaning + switch check + battery replacement doesn’t solve it, replace the unit. Time and frustration cost money too.
Project owners / EPCs:
Ask:
- Are failures random or systematic (same sections / same weather / same batch)?
- Is this a one-off component issue, or a sizing/config mismatch?
- How much are you spending on night call-outs, trucks, fuel, and complaints?
If poles and foundations are still good, a retrofit can be smarter than full replacement:
- keep civil works
- upgrade lamp head efficiency/optics
- resize battery/panel or adjust dimming curve
- add monitoring for faster O&M decisions
Check 10: Project-Level Diagnosis (Municipal / EPC)
A road section going dark repeatedly is a safety + reputation + budget problem.
A practical approach:
- Map failures by road segment + installation batch
- Compare “good section” vs “bad section”
- Check correlation with rainy season / shading corridor / schedule settings / sealing signs
- Sample measurements (not every pole): panel output, battery voltage at dawn and after charge, connector/cable inspection
If failures appear after 3–4 cloudy days every year, you likely need system resizing or re-profiling, not endless patch repairs.
FAQ
Why does my solar light only stay on for a few hours?
Common causes:
- dirty/shaded panel
- weak battery
- power profile too aggressive for the available solar resource
Can I use non-rechargeable batteries in a solar light?
No. Non-rechargeable alkaline batteries are not designed to be charged and can leak or fail dangerously. Use recommended rechargeable types.
Why do solar street lights fail after rainy seasons?
Common project causes:
- autonomy too low (undersized battery/panel)
- water ingress / corrosion
- poor battery cycle life
- surge/lightning exposure without adequate protection
Need a Second Opinion on a Troubled Project?
If you’re seeing:
- high failure rate across a section
- repeating rainy-season blackouts
- too many night call-outs and complaints
Send:
- photo of the lamp label (power, battery, panel specs)
- photo of opened battery box / internal wiring
- project location + year + number of poles
- failure pattern (which sections, when it fails)
We can help you decide whether the right move is targeted repair, partial retrofit, or a system re-profile—based on patterns, not guesses.
