--- title: "Battery & Inverter Sizing for Backup Power Explained | Qyvea Kenya" url: https://qyvea.co.ke/battery-and-inverter-sizing-kenya description: "How to size backup batteries and inverters: adding up loads in watts, runtime in hours, usable capacity (depth of discharge), lithium vs lead-acid, and surge loads." updated: 2026-10-17 --- > Markdown copy of https://qyvea.co.ke/battery-and-inverter-sizing-kenya for AI assistants. Prices and stock change; check the live page. 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A generator needs fuel, noise and someone awake to start it. Read on: it takes a few minutes and could save you a lot more than that. **In this guide you will see:** - Inverter size = peak load (watts), with headroom for surges. - Battery energy = load × hours ÷ usable depth of discharge. - Lithium gives more usable capacity and longer life than lead-acid. Quick answer The inverter must handle the total power of everything running at once (plus start-up surges); the battery must store enough energy for the runtime you need. Energy needed = load (W) × hours. Because batteries shouldn't be fully drained, divide by the usable fraction: about 80–90% for lithium (LiFePO4), often around 50% for lead-acid. [Photo: Andre Taissin / Unsplash](https://unsplash.com/photos/LBPU8K7loz8) Why this matters now ## Each outage you wait through is another night your protection depends on the grid. ### If you wait - Fence, cameras and lights go off together - Recorders restart badly or lose footage - A generator needs fuel and attention ### What you get - Batteries carry your essentials through the outage - Solar reduces what you buy from the grid - Sized to the load you actually have [Jinko Solar 450W Mono](/products/jinko-solar-450w-mono-perc-solar-panel-102 "Jinko Solar 450W Mono PERC Solar Panel")[Must 6kva solar inverter](/products/must-6kva-solar-inverter-28900 "Must 6kva solar inverter")[200Ah 24V LiFePO4 Lithium](/products/200ah-24v-lifepo4-lithium-battery-pack-413 "200Ah 24V LiFePO4 Lithium Battery Pack") [Get my free quote on WhatsApp](https://wa.me/254113301244?text=Hi%20Qyvea%2C%20I%20read%20your%20guide%3A%20Battery%20%26%20Inverter%20Sizing%20for%20Backup%20Power.%20I%20want%20solar%20and%20backup%20power%20sorted.%20Can%20you%20help%3F)Reply usually within 30 minutes. Free site survey in Nairobi and nearby counties. Real products, live prices, in stock now ## Key takeaways - Inverter size = peak load (watts), with headroom for surges. - Battery energy = load × hours ÷ usable depth of discharge. - Lithium gives more usable capacity and longer life than lead-acid. - Measure real loads; don't guess. - Security loads are small and constant, ideal for backup. ## Worked example 1. **List the loads**: NVR + 8 cameras (PoE switch) ~150 W, router 15 W, fence energizer ~20 W, gate standby ~10 W: about 200 W 2. **Decide runtime**: 8 hours overnight 3. **Energy needed**: 200 W × 8 h = 1,600 Wh 4. **Allow for depth of discharge**: Lithium at 80%: 1,600 ÷ 0.8 = 2,000 Wh (2 kWh) 5. **Add margin**: Losses and battery ageing: choose around 2.5 kWh **Important**: Figures above are illustrative. Real loads are measured on site, and IR, heaters and gate openings change consumption. ## Lithium vs lead-acid | | Lithium (LiFePO4) | Lead-acid | | --- | --- | --- | | Usable capacity | About 80–90% | Often around 50% for good life | | Cycle life | Much longer | Shorter | | Weight | Lighter | Heavier | | Upfront cost | Higher | Lower | | Cost over its life | Often lower | Often higher | ## Inverter sizing - Add up everything that runs at once - Motors (pumps, gate motors, fridges) draw a surge at start-up - Choose an inverter with continuous rating above the load and surge rating above the peaks - Put security loads on a dedicated backed-up circuit See [on-grid vs hybrid](https://qyvea.co.ke/on-grid-vs-hybrid-vs-off-grid-solar-kenya) and [changeover switches](https://qyvea.co.ke/automatic-changeover-switches-kenya). ## Frequently asked questions How long will my batteries last in an outage? Usable battery energy (Wh) divided by the load (W) gives the hours, e.g. 2,000 Wh ÷ 200 W = 10 hours. Can I run everything in the house on backup? Possible but expensive. Most people back up essential circuits: security, lights, router, fridge. Why did my inverter trip when the pump started? Motor start-up surges can exceed the inverter's surge rating. ## Why customers choose Qyvea **Genuine brands**: Manufacturer warranty on what we sell, so you are not gambling on the box. **One team, start to finish**: The people who advise you also install and support it. **Fast answers**: WhatsApp replies usually within 30 minutes, and delivery within 24 hours in Nairobi. **Easy to buy**: Pay by M-Pesa, bank transfer or card. Free delivery in Nairobi on orders over KES 5,000. **Risk taken off you**: 7-day returns and exchanges on products, and a workmanship warranty on installations. **Customers say so**: Rated 4.6/5 from 57 Google reviews. **Your next step takes one minute:** send us a photo of the place on WhatsApp and we will tell you what it needs. ## Related articles [Solar & Electrical · Guide Solar Backup for Security Systems Keeping CCTV, fences, gates, access control and the router running when the power goes, and why it's cheaper than backing up a whole building. 2 min read**READ FULL ARTICLE →**](https://qyvea.co.ke/solar-backup-for-security-systems-kenya)[Solar & Electrical · Comparison On-Grid vs Hybrid vs Off-Grid Solar Which solar system keeps the lights (and cameras) on when KPLC goes off? On-grid, hybrid and off-grid compared. 2 min read**READ FULL ARTICLE →**](https://qyvea.co.ke/on-grid-vs-hybrid-vs-off-grid-solar-kenya)[Solar & Electrical · Guide Security System Backup Power Keeping CCTV, fences and gates running when the power goes. 3 min read**READ FULL ARTICLE →**](https://qyvea.co.ke/security-system-backup-power-kenya) ### Related services [Solar Backup Solutions](https://qyvea.co.ke/solar-solutions)[Security Backup Power](https://qyvea.co.ke/security-system-backup-power-kenya)[Electrical Installation](https://qyvea.co.ke/electrical-installation) ### Related products [5kW hybrid solar kit](https://qyvea.co.ke/solar-hybrid-system-5kw-kit-kenya)[Best solar backup systems](https://qyvea.co.ke/best-solar-backup-system-kenya) ### Related projects [Real Qyvea case studies](https://qyvea.co.ke/projects#case-studies) [← Previous**Automatic Changeover Switches Explained**](https://qyvea.co.ke/automatic-changeover-switches-kenya)[Next →**: Best Solar Water Heater in Kenya: How to Choose**](https://qyvea.co.ke/best-solar-water-heater-kenya) ## Need this system installed? 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