Solar Kit Calculator

It depends on how much electricity you use daily. Add up the wattage of all appliances you want to run and multiply by the hours per day you use them - that gives your daily watt-hours (Wh). Divide that by Zambia's average of 5.5 peak sun hours and an 80% efficiency factor to get the panel capacity you need. This calculator does all that for you.

Your battery must store enough energy to power your home through the night and any cloudy periods. For an off-grid system, we size for 2 days of autonomy. For a grid-supported setup (ZESCO backup), we size for 0.75 days - enough to cover load-shedding. AGM batteries are discharged to 50% to protect their lifespan, so the battery bank must be double your actual energy needs.

Off-grid means your solar system is your only power source - there is no ZESCO connection. You need larger panels and more battery storage to survive multiple cloudy days. Grid-supported (hybrid) means ZESCO is your primary supply but solar kicks in during load-shedding. You need less battery capacity because ZESCO recharges your batteries when power is on. Most urban Zambian households benefit most from grid-supported.

Deep-cycle AGM batteries are the best mid-range choice for most Zambian households - they are widely available, reliable, and cost significantly less upfront. Lithium LiFePO4 batteries cost more but last 2-3 times longer, charge faster, and can be discharged deeper (up to 80%). Over 10 years, lithium often works out cheaper per cycle. This calculator recommends AGM by default and shows you the lithium upgrade cost.

An MPPT (Maximum Power Point Tracking) charge controller manages the power flowing from your panels to your batteries. It is essential - without one, excess panel voltage is wasted as heat. MPPT controllers are 20-30% more efficient than older PWM types. This calculator recommends an MPPT controller sized at 125% of your panel current for safety headroom.

Example: A home running 4 LED lights (10W each, 6hrs), a fridge (100W, 24hrs), and a TV (80W, 5hrs). Daily load = 240 + 2,400 + 400 = 3,040 Wh. Panels needed = 3,040 / (5.5 sun hrs x 0.8 efficiency) = ~760W. Battery bank (off-grid, 2-day autonomy, 50% DoD) = 3,040 x 2 / (12V x 0.5) = ~1,013Ah. Inverter = at least 190W peak load.