How Kenyan Households Should Size Reliable Solar-Battery Backups for Frequent Grid Interruptions(Jan.2023)
A practical guide for Kenyan households: define essential loads first, then match usable battery capacity, inverter surge power and daytime solar recharge to the actual outage pattern.
Question answered
How should a Kenyan household choose solar-battery backup for essential loads during grid interruptions?
Market context: 2023-01
Guide
## The practical answer Do not begin by trying to back up the entire home. Start with the circuits that protect comfort, communications and safety during an interruption: lighting, refrigerator, internet equipment, phones, a few sockets and—where needed—a small water pump. The right system is the smallest one that can run those **essential loads** reliably, recharge during the available solar window and handle the highest motor starting surge. A qualified installer should validate the final design on site. ## 1. Separate essential and flexible loads Put critical loads on a dedicated backup circuit. These often include LED lights, Wi-Fi, security equipment, refrigeration, devices for work or study, and a small pump. Keep high-heat appliances such as electric showers, irons, cookers and large air-conditioning units off the battery circuit unless the project has been specifically engineered for them. This one decision prevents an expensive system from being oversized for equipment that does not need overnight backup. ## 2. Size battery energy around the outage window List each essential appliance, its power and the hours it must run while the grid is unavailable. Add those energy needs in kilowatt-hours, then choose battery capacity with room for normal inverter losses and a sensible reserve. For example, a compact household critical-load plan may combine lighting, refrigeration, communications and charging. The exact capacity depends on actual appliance duty cycles, especially the refrigerator and pump. The important question is not “How large is the house?” but “What must still work, for how long?” > **Sizing note:** battery capacity should cover the critical-load energy requirement after allowing for permitted battery discharge and inverter efficiency. ## 3. Match inverter power to the highest starting load Battery energy and inverter power are different decisions. A refrigerator or pump may draw much more power for a short moment when it starts than when it is running. Check the inverter's continuous rating and surge capability against the largest expected simultaneous load. Do not assume a generator rating translates directly into a solar-storage inverter size. ## 4. Make daytime solar do two jobs The PV array must support daytime use **and** replenish energy used overnight. Roof orientation, shading, panel cleanliness and seasonal weather all affect this. A system that looks adequate on a sunny day can disappoint if the battery is not refilled after several poor-solar days. Ask the installer to show the expected daily energy balance and the fallback plan when solar production is low. ## Quick installer checklist - Measure real running and starting power for motors, refrigeration and pumps. - Confirm which circuits are on the backup board and label them clearly. - Verify inverter-to-battery communication, isolation, earthing and surge protection. - Check ventilation and operating temperature at the planned equipment location. - Explain what the system will not power during an outage. ## When engineering review is essential Request a site-specific design if the home has large pumps, workshop machinery, three-phase supply, medical equipment, electric cooking or air-conditioning that must run through an outage. These loads require detailed measurement, protection coordination and a tailored single-line design.