(Now with visual image sections under every key point for better readability)

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1️⃣ Calculate Your Total Daily Energy Consumption

This is always where I begin.

Before I size any solar component, I calculate total daily energy usage in watt-hours (Wh).

Example Load Table:

Appliance	Power (W)	Hours Used	Daily Usage (Wh)
LED lights	60W	5 hrs	300Wh
TV	120W	4 hrs	480Wh
Fridge	150W	8 hrs	1200Wh
Fans	150W	6 hrs	900Wh

Total = 2,880Wh/day

Then I add 20–30% system losses.

Adjusted total ≈ 3,600Wh/day

This figure determines everything else.

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2️⃣ Properly Size the Battery Bank

Batteries power the home at night. If undersized, the system fails after sunset.

What I Calculate:

• Daily energy requirement
• Days of autonomy (usually 1–2 days)
• Battery voltage
• Depth of discharge

Example:

Daily need = 3,600Wh
2 days autonomy = 7,200Wh

Using 48V lithium:

7,200 ÷ 48 = 150Ah

Recommended battery:
✔ 48V 150Ah lithium battery (minimum)

For lead-acid, I double capacity due to 50% usable limit.

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3️⃣ Properly Size the Solar Panel Array

Panels must recharge batteries daily.

Formula I Use:

Daily Energy ÷ Peak Sun Hours = Required Solar Wattage

If location gets 5 peak sun hours:

3,600Wh ÷ 5 = 720W
Add 25% losses → ≈ 900W

I would install:

✔ 3 × 400W panels (1,200W total)

I slightly oversize to handle cloudy days.

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4️⃣ Choose the Correct System Voltage

4

Voltage impacts system efficiency.

Here’s how I decide:

• Small loads → 12V
• Medium systems → 24V
• Larger homes → 48V

Higher voltage means:

✔ Lower current
✔ Smaller cables
✔ Less power loss
✔ Higher efficiency

Most homes I design use 48V.

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5️⃣ Properly Size the Inverter

4

The inverter must handle:

• Total running load
• Surge load (startup spikes)

If running load = 1,000W
I choose at least:

✔ 3kVA pure sine wave inverter

Because appliances like fridges and pumps draw 2–3× startup power.

Undersized inverters cause overload shutdown.

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6️⃣ Size the Charge Controller (If Separate)

If using a separate controller:

Controller rating ≥ Total panel current

I always prefer:

✔ MPPT controller

Why?

• Higher efficiency
• Better performance in cloudy weather
• Supports higher voltage arrays

Never undersize the controller.

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7️⃣ Account for Surge Loads

4

Motors draw high startup current.

Examples:

• Fridge
• Pump
• AC

Rule I follow:

Largest appliance × 3 = Required surge capacity

Your inverter must handle that.

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8️⃣ Include Proper Protection & Cable Sizing

Sizing is not complete without protection.

I always include:

✔ Correct cable thickness
✔ Battery breaker/fuse
✔ AC output breaker
✔ Earthing system
✔ Surge protection devices

Undersized cables waste power and overheat.

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Example Final System for 3.6kWh/day Home

• 1.2kW solar panels
• 48V 150Ah lithium battery
• 3kVA inverter
• MPPT controller
• Complete protection system

Balanced. Reliable. Efficient.