Install solar right.
Safe, sized, and built to last.

01 Safety first

Electricity can kill. A current of only 50 mA through the body can stop the heart. Solar panels produce power whenever the sun shines — you cannot switch off the sun.

The 5 rules before working on any electrical installation

1. Disconnect. Switch off breakers, remove fuses, open the main switch and the DC isolator.
2. Secure against reconnection. Lock the switch or take the fuses with you. Put up a warning sign.
3. Test for absence of voltage. Use a two-pole voltage tester. Never trust a switch position alone.
4. Earth and short-circuit (for systems above 1000 V and overhead lines).
5. Cover nearby live parts with insulating material before you start.

Working on roofs

• Use fall protection when working near a roof edge above 2 m: guardrails first, harness with anchor point if guardrails are not possible.
• Check the roof structure before loading it with panels and people. Old timber or rusted sheets may not carry the weight.
• Never work on a metal roof during thunderstorms. Stop work when rain makes the roof slippery.
• Wear a helmet, gloves and shoes with grip. Keep tools tied or in a bag — a falling spanner can injure people below.

02 Electricity basics

Three quantities describe every circuit: voltage U (volts), current I (amps) and resistance R (ohms).

Power P (watts) and energy E (watt-hours) are what customers pay for:

Series and parallel

• Series (panels in a string, cells in a battery bank): voltages add, current stays the same.
• Parallel (strings side by side): currents add, voltage stays the same.

03 The sun in Ghana

Ghana has an excellent solar resource: roughly 4.5 to 5.5 peak sun hours (PSH) per day, depending on region and season. One peak sun hour equals 1000 W/m² of sunshine for one hour.

• North (Tamale, Bolgatanga): ~5.0–5.5 PSH — very strong, drier climate.
• Middle belt (Kumasi): ~4.5–5.0 PSH — more clouds in the rainy seasons.
• Coast (Accra, Takoradi): ~4.5–5.0 PSH.

Tilt and orientation

• Ghana lies close to the equator (5–11° N). The yearly optimum tilt is small — about equal to the latitude.
• Use at least 10° tilt anyway, so rain can wash dust off the panels. Flat panels stay dirty and lose power.
• Face the modules towards the south where possible; east or west costs only a little yield at this latitude.
• Avoid all shade between 9:00 and 15:00 — trees, water tanks, antennas, parapet walls. Even a small shadow can cut a whole string's output.

04 System types

Charge controllers

• PWM: cheap, fine for small systems where panel voltage matches battery voltage.
• MPPT: 10–30 % more harvest, allows higher panel voltage and longer cable runs. Recommended for most systems.

Batteries

• LiFePO4 (lithium): long life (3000+ cycles), 80–90 % usable depth of discharge, safe chemistry, no maintenance. Best value over its lifetime.
• Lead-acid / gel: cheaper to buy, but only ~50 % usable and shorter life, especially in heat. Keep them cool, ventilated and charged.
• Heat shortens battery life. Install batteries in the coolest, shaded, ventilated place available — never in direct sun or a hot metal container.

05 Sizing a system — step by step

Step 1 — Daily energy need

List every load: power (W) × hours per day = watt-hours (Wh). Add them up.

Example: 4 LED lamps 10 W × 5 h = 200 Wh · TV 60 W × 4 h = 240 Wh · fridge ≈ 800 Wh · phone charging 30 Wh → ≈ 1270 Wh/day.

Step 2 — Solar array

PR is the performance ratio: use 0.70 for battery systems (heat, dust, cable, charging and inverter losses), 0.75–0.80 for grid-tied.

Step 3 — Battery bank

Days of autonomy: 1–2 for hybrid with grid backup, 2–3 for full off-grid. DoD: 0.8 for lithium, 0.5 for lead-acid. η (battery + inverter efficiency): ≈ 0.85.

Step 4 — Inverter

Inverter power ≥ the sum of loads that run at the same time, plus reserve for motor start-up (fridges and pumps need 3–5 × their rated power for a moment). Choose a pure sine wave inverter.

Step 5 — Cables

L = one-way cable length in m, I = current in A, ΔU = allowed voltage drop in volts (aim for max. 3 % on the battery side — that is only 0.36 V in a 12 V system!). 56 is the conductivity of copper. Low-voltage battery systems need thick cables.

06 Installation best practice

Mounting

• Fix the rails to the roof structure (rafters/purlins), never only to the roofing sheet.
• Use stainless or hot-dip galvanised hardware — coastal air and rainy seasons corrode ordinary steel fast.
• Do not mix bare aluminium and copper directly: galvanic corrosion. Use suitable bimetal or stainless connectors.
• Clamp modules only in the zones the manufacturer allows. Torque the clamps to specification.

Wiring

• Use UV-resistant solar cable (PV1-F type) outdoors and genuine, matching MC4 connectors — never mix brands or improvise with tape.
• Fix cables every 30–50 cm; no cable should touch the hot roof sheet or hang in water.
• Fuse every parallel string when more than two strings share one input.
• Keep DC plus and minus of the same string together (small loop area = less lightning-induced voltage).

Earthing and lightning

• Bond the module frames and mounting rails to earth (min. 6 mm² copper, 10–16 mm² for larger systems).
• Install surge protection (SPD Type 2) on the DC side near the inverter and on the AC side — thunderstorms are frequent and intense in Ghana.
• Drive a proper earth rod; measure the earth resistance, do not guess.

07 Maintenance

• Clean the modules with water and a soft brush early in the morning — never with cold water on hot glass. More often during Harmattan.
• Check yields monthly. A sudden drop means shading, dirt, a failed string or a tripped fuse.
• Inspect yearly: connectors (discoloured = hot = danger), cable fixings, corrosion on the mounting, tightness of clamps, surge protectors (replace after big strikes), inverter error log.
• Batteries: keep terminals clean and tight; for lead-acid check electrolyte level and equalise as the maker specifies; keep the room ventilated.
• Cut back trees and bushes before they shade the array.

08 Quick reference

Copper cable — maximum current (guide values)

Derate in hot conduits and bundles. For battery cables, the voltage drop usually decides, not the current rating.

Key formulas

Typical loads