Solar & Battery Sizing for Colombo, Sri Lanka
The short answer: Colombo sits at 6.93° N, 79.85° E — tropical sun. Near-constant day length and strong year-round sun; the least seasonal solar resource on Earth. Roughly 1500–1900 kWh per kW of panels per year is a fair expectation band, and the exact number for your roof is what the simulator computes.
What the calculator does for Colombo
Type "Colombo" (or use your exact GPS coordinates) into the estimator and it will:
- Simulate five years of hourly NASA satellite weather for your location — not a yearly average, the actual hourly series including bad weeks.
- Size grid-tie bill-cutting systems at 60%, 80%, and 95% targets, with payback from your own tariff.
- Size fully off-grid systems at three reliability tiers — from "never needs a generator" to "a few generator hours a year".
- Compare battery chemistries by true lifetime cost: LiFePO4, sodium-ion, and lead-acid including replacement cadence.
- Produce a hardware parts list with panel count, bank configuration, inverter class, and cable gauges, exportable as CSV.
Worked example: a 10 kWh/day household
Using the Colombo latitude band (1500–1900 kWh/kWp/yr), a household using 10 kWh per day typically lands in this range — a rough illustration from the band (with a dark-week margin), not a simulation; your exact figures come from running it:
| Bill cut | Typical panels | Typical battery |
|---|---|---|
| ~60% | 1.5–2.5 kW | 3–5 kWh |
| ~80% | 2–3.5 kW | 4–7 kWh |
| ~95% | 2–4 kW | 5–9 kWh |
Payback depends on your local tariff: at ~$0.08/kWh a 60% cut on this load saves roughly $175/year, which repays landed-DIY component costs (about $1,492) in about 8.5 years. Where power is cheap, payback stretches — the tool shows your personal number from your own rate.
Why simulate instead of estimate?
Sun-hours maps and "average" figures hide the week that decides your battery size. In tropical sun conditions, near-constant day length and strong year-round sun; the least seasonal solar resource on Earth. A five-year hourly simulation catches that dark week, the cloudy month, and the seasonal swing — which is the difference between a system that works and one that leaves you in the dark in February.
Run the Colombo simulation now. Free, no signup, nothing for sale. Every number computed in your browser from real satellite weather.
⚡ Size my Colombo systemOther cities
Related guides
- How to cut your electricity bill with solar (honest math)
- Is a home battery worth it?
- Off-grid vs grid-tied: which pays back faster?
- What size solar system for off-grid?
- About the method (NASA weather, derates, update cadence)
Frequently asked
How much solar do I need in Colombo?
It depends on your daily kWh use. As a rough band, Colombo sits in the tropical sun zone with roughly 1500–1900 kWh produced per kW of panels per year. A 10 kWh/day household typically lands between 3 and 6 kW of panels depending on the bill-cut target. The free calculator computes your exact numbers from five years of NASA satellite weather at your coordinates.
Does solar work in Sri Lanka?
Yes — Tropical sun at 6.93° N, 79.85° E. Near-constant day length and strong year-round sun; the least seasonal solar resource on Earth. The simulator sizes against your worst week, not the average, so the result is honest about winter.
Is the Colombo solar calculator free?
Completely. No signup, no email, nothing for sale. You type your city or coordinates, enter your bill or daily usage, and get off-grid tiers, bill-cut scenarios, payback, and a hardware parts list — all computed in your browser.