Off-Grid Solar System Sizing Made Simple for Kenyan Homes and Businesses.

Easily estimate your daily energy usage and get accurate recommendations for the ideal battery capacity (Ah), solar panel size (W), and total power consumption (Wh) using our easy-to-use solar calculator.

How to Use the Off-Grid Solar System Sizing Calculator

A Simple Step-by-Step Guide for Anyone Going Solar

Thinking of switching to solar power and living off the grid? Our calculator helps you find out how many solar panels and what size battery bank you need — no technical skills required.

Step 1: List Your Daily Appliance Usage.

Write down the things you use every day — like lights, TV, fridge, phone charger — and how many hours you use each.

Example: A 100-watt (W) TV used for 5 hours = 500 watt-hours (Wh) of energy.
The calculator will do the math for all your items.

Step 2: Select System Voltage.

Choose either 12V, 24V, or 48V depending on your setup.

• 12 volts (V) – Common for small homes or cabins.
• 24 volts (V) – Good for medium homes.
• 48 volts (V) – Used for larger systems with higher power needs.

Step 3: Choose Days of Backup Power (Autonomy).

How many cloudy or rainy days should your batteries support you without sunshine?

Example: 2 days of backup means your battery should store 2 days’ worth of energy.

Step 4: Select Battery Discharge Level.

This is how much of your battery’s power you’re okay using before recharging.

• For lead-acid batteries, use only 50% to make them last longer.
• For lithium batteries, you can safely use up to 80–90%.

Step 5: Enter Inverter Efficiency.

Some energy is lost when converting solar power for your appliances.

• A typical inverter is about 90% efficient, meaning 10% is lost.
• The calculator factors this in automatically.

Step 6: Add Your Average Sunlight Hours.

Enter how many sunny hours your location gets daily.
In most parts of Kenya, this is around 4–6 hours per day.

What the Calculator Shows You.

• Battery Size (Ah – Amp-hours):
  How much electricity your battery bank can store. More Ah = longer power backup.
• Solar Panel Size (W – Watts):
  How much power your solar panels need to produce at once to meet your energy needs.
• Total Energy Use (Wh – Watt-hours):
  The total energy your appliances use in a day.

Need help or want a custom quote?
Visit RiisunSolarEnergy.co.ke or contact us today. We’re here to guide you through your solar journey!