Load & Backup Calculator
Size batteries for fans, fridge, lights, and load shedding backup.
Step-by-step landing pages for this calculator — pre-filled loads and FAQs.
- Use-case guideBackup for 500W LoadA ~500 W essential load (2 fans, fridge, TV, lights, router) for 4 hours needs about 2.3 kWh — typically 12V 200Ah LiFeP…
- Use-case guideShop & Retail Backup PowerRetailers need POS, LED panels, and often CCTV online 8+ hours; lithium reduces floor space vs tubular.
- Use-case guideHome Office Backup PowerWork-from-home setups need laptop, monitor, router, and often a fan running 4–6 hours per outage.
- Use-case guideBattery for 1 Ton AC Backup1 ton inverter AC averages ~1,000–1,400 W when compressor runs. Backup requires large kWh (often 5–15 kWh) and 48V-class…
- Pillar guideHome Backup Power GuideInverters, lithium UPS, and load shedding strategies for Pakistani homes.
75W per unit × 2 = 150W for this row
What this calculator does
Estimates total household or shop load and the battery capacity required to survive load shedding for your chosen backup hours.
How calculations work
- Add appliances from the Pakistan household and business list, or enter custom wattage.
- Set quantity and required backup hours (typical load shedding window: 2–6 hours).
- We calculate total load (W), energy needed (Wh), and recommended voltage and Ah using depth-of-discharge for your battery type.
- Inverter/UPS VA suggestion includes a 40% headroom factor for motor and surge loads.
Examples
≈75+75+250+12 = 412 W → ~1,900 Wh → 12V 200Ah LiFePO4 class bank for essentials during evening outages.
≈50+120+80 W × 8 h → consider 24V lithium for efficiency on longer commercial backup.
Common mistakes
- Using nameplate watts for fridges and AC without duty-cycle (use average draw or our presets).
- Ignoring inverter efficiency (we add ~15% margin on Wh).
- Sizing lead-acid to 100% depth of discharge — use 50% DoD for flooded/tubular.
FAQs
Relevant landing pages
Dedicated guides with pre-filled calculator settings for common Pakistani setups.
Backup for 500W Load
A ~500 W essential load (2 fans, fridge, TV, lights, router) for 4 hours needs about 2.3 kWh — typically 12V 200Ah LiFeP…
Shop & Retail Backup Power
Retailers need POS, LED panels, and often CCTV online 8+ hours; lithium reduces floor space vs tubular.
Home Office Backup Power
Work-from-home setups need laptop, monitor, router, and often a fan running 4–6 hours per outage.
Battery for 1 Ton AC Backup
1 ton inverter AC averages ~1,000–1,400 W when compressor runs. Backup requires large kWh (often 5–15 kWh) and 48V-class…
Home Backup Power Guide
Inverters, lithium UPS, and load shedding strategies for Pakistani homes.