Port Harcourt gets some of the heaviest rainfall in Nigeria, with the wet season running roughly from March or April to October. So the question we hear in every site visit is fair: does solar still work when it rains?
Yes, but sizing for the rainy season matters
Solar panels respond to daylight, not just direct sun. Under cloud they keep producing, just less:
| Sky | Output compared with a clear day |
|---|---|
| Clear, dry season | 100% |
| Light cloud / haze | 60–80% |
| Overcast | 30–50% |
| Heavy rain clouds | 15–30% |
Across a year, the Niger Delta averages roughly 4.4 to 4.6 peak sun hours a day (Rivers about 4.5, Delta about 4.6, Bayelsa about 4.4), with the rainy months below that average. A system sized on dry-season sunshine will look great in January and struggle in July. Ours are sized for rainy-season conditions, and the solar calculator does the same.
Two things keep you powered through a run of cloudy days:
- Enough panels. A bigger array refills the battery even on a dull day. See how many panels a 5kVA inverter needs.
- A hybrid inverter. It can top up from grid or generator when solar falls short. See hybrid vs off-grid.
Harmattan and soot
Harmattan reaches the Niger Delta in a milder form than the north, but the haze and dust still settle on panels. In Port Harcourt, soot from generators and illegal refining adds a black film. Left alone for a few months, dirt can cut output noticeably. A rinse brings it back.
Simple maintenance checklist
Every 4–6 weeks (dry season)
- Rinse the panels with clean water early in the morning or late afternoon, using a soft brush or sponge on a long pole. Only climb onto the roof if it is safe; on an upstairs building, leave it to someone with proper access equipment.
- Look for new shade: a growing tree, a new water tank, a neighbour's new floor.
Every month
- Check the inverter display for error codes or warnings.
- Note the battery level at sunrise. If it is dropping lower than it used to, something has changed.
- Make sure the battery room is dry, ventilated and not used as a store for paint, fuel or clothes.
Every rainy season
- Check that the roof penetrations are not leaking.
- Confirm surge protection devices are intact after storms. Thunderstorms are common, and good earthing and surge protection are the system's lightning defence.
- In flood-prone areas, make sure the inverter and battery are still above the flood line. Our flood guide covers this in detail.
Every year
- Have a technician check torque on cable connections, test the earthing, inspect the mounting rails and update inverter firmware if needed.
Warning signs to act on quickly
- Burning smell or discoloured cables near the inverter
- Inverter fan running loud and hot all day
- Battery swelling (lead-acid) or BMS alarms (lithium)
- Panels producing far less than the same month last year
If you see any of these, switch off at the isolator and get the system checked. Our battery lifespan guide explains the most common causes of early battery failure.
