Anyone who has lived through a Lagos July or a Kano January knows the sun is not constant. Systems that work here are sized for the worst month, not the average — and cleaned when the dust comes.
Key facts
- Rainy-season output can fall 30–40% below the dry-season peak on cloudy weeks.
- Harmattan dust cuts output 5–15% within days if panels aren't cleaned.
- Arrays are sized to the worst month for critical loads; batteries carry 10–15% extra at sites without grid.
- Monitoring shows the daily yield, so cleaning and backup are triggered by data, not guesswork.
Sizing for July, not March
A design that meets the load in the dry season and fails in August is a failed design. We size critical-load arrays to the lowest monthly yield, use the surplus in good months to run non-critical loads, and keep the grid or gas backup for the exceptional week of continuous cloud.
Dust
Harmattan haze and dust settle on panels and can take 10% or more of output in a fortnight. Monitoring shows the drop; a cleaning crew is scheduled before it becomes a problem. Ground-mount arrays are easier to clean, which is one reason mills and camps use them.
Cold rooms don't notice
Because the cold room's battery is sized for the overnight load with margin, and because pre-cooling and thermal mass carry hours of shortfall, a cloudy day shows up in the dashboard, not in the product temperature.
Want a system sized for August, not a brochure?
Talk to Frontières BayFrequently asked
How often are panels cleaned?
Monthly in dusty seasons, quarterly otherwise; triggered earlier by a yield drop in monitoring.
Does rain clean the panels?
Partly — but rain also brings the clouds; the cleaning schedule is set by data.