What is the difference between Day-Only and Day-and-Night Solar system costs?

A Day-Only system relies on solar panels and an on-grid/hybrid inverter to run appliances directly during sunshine hours without large battery banks. A Day + Night system includes a heavy tubular or lithium battery storage bank to power heavy loads during night load-shedding, increasing initial capital expenditure.

Solar Calculator Pakistan | Inverter & Battery Sizer

Q: Why is a 20% safety buffer added to solar and inverter load calculations?

Inductive appliances like air conditioners, refrigerators, and water pumps draw 2 to 3 times their running wattage during motor startup (surge inrush current). A 20% to 25% safety overhead prevents inverter overload trips and accounts for ambient temperature derating during Pakistani summer peak temperatures.

Q: What is the difference in solar requirements between Inverter and Non-Inverter ACs?

A conventional 1.5 Ton split AC draws a continuous 1,800W to 2,200W, requiring at least a 3.6kW to 5kW inverter and 4 to 5 solar panels per unit. A 1.5 Ton DC Inverter AC throttles its compressor speed, consuming between 500W and 1,200W once stabilized, drastically reducing battery drain and panel count.

Q: How do I calculate battery backup Ah for load shedding?

Battery capacity is calculated as: (Total Watts x Required Hours) / (System Voltage x Depth of Discharge x 0.85 Efficiency). For tubular lead-acid batteries, Depth of Discharge (DoD) is 50%, whereas LiFePO4 Lithium batteries provide 85% to 90% usable capacity.

Use this free Pakistan Solar & UPS Load Calculator to size your complete solar system — hybrid inverter, 585W panels, tubular or lithium battery bank, and total cost in PKR. Pre-loaded with standard Pakistani household appliances; edit wattages, quantities, and operating hours to match your actual usage. All calculations include a 20% safety buffer for motor surge currents and summer derating.

Add Appliance

Appliance	Watts	Qty	Day Hrs	Night Hrs	Subtotal (W)
Standard AC Ceiling Fan					320
LED Bulb (12W)					96
1.5 Ton Inverter AC					1200
Inverter Refrigerator					90
1 HP Water Pump					750
Electric Dry Iron					1000
32" LED TV					45
Wi-Fi Router					15
Total Running Load					3,516 W

Battery Chemistry

Backup Hours

System DC Voltage

Hybrid Inverter

6.0 kW

48V system • 20% buffer applied

Solar Panels (585W)

8 Panels

4.68 kW array • 5.2 PSH

Battery Bank

368 Ah

48V Tubular • 4 hrs backup

Estimated System Costs (PKR)

Solar PanelsRs 168,480

Hybrid InverterRs 192,000

L3 Structure + CablesRs 55,000

Day-Only SystemRs 415,480

Day + Night Backup System

Battery BankRs 520,000

Day System (above)Rs 415,480

Installation & WiringRs 35,000

Full Day+Night SystemRs 970,480

Balance of System (BOS): DC Solar cable 6mm² XLPO • Battery interconnect 35mm² flexible Cu • DC breaker 63A • AC breaker 32A • Earthing kit • MC4 connectors

Costs are approximate estimates based on current Pakistani market rates (Aug 2026). Panel ~Rs 36/W, Inverter ~Rs 32/W, Tubular 200Ah ~Rs 65,000, Lithium ~Rs 72,000/kWh. Actual prices vary by brand and installer.

How to Use This Calculator

Review pre-loaded appliances — the table starts with a typical Pakistani household setup. Edit wattages, quantities, and operating hours to match your actual usage.
Add or remove appliances — use the dropdown to add more items. Delete any row you don’t need. Inverter and non-inverter versions are listed separately with accurate default wattages.
Choose battery settings — select tubular lead-acid or lithium LiFePO4, backup hours (2–8), and system DC voltage. Results update instantly.
Read your sizing — the calculator shows the recommended hybrid inverter (with 20% safety buffer), number of 585W solar panels, and battery bank capacity in Ah/kWh.
Check estimated costs — two cost breakdowns: day-only solar (net metering) and full day+night backup with battery bank.

Inverter vs Non-Inverter Appliances — Why It Matters

The single biggest factor in your solar system size is whether your appliances use inverter technology. A 1.5 Ton Inverter AC draws 1,200W when stabilized, compared to 2,000W for a conventional unit — a 40% reduction that directly shrinks your inverter, panel count, and battery bank.

The same applies to refrigerators: an inverter fridge runs at roughly 90W average vs 180W for conventional. And BLDC inverter ceiling fans pull just 35W instead of 80W. When sizing a solar system for load shedding in Pakistan, switching to inverter appliances before installation saves lakhs in total system cost. For a deeper look at how solar fits into the broader landscape of renewable energy sources, see our full guide.

Battery Sizing Guide — Tubular vs Lithium

Battery capacity is calculated as: (Total Watts × Backup Hours) ÷ (System Voltage × DoD × Efficiency).

Tubular Lead-Acid (Phoenix, AGS, Osaka): 50% usable depth of discharge, ~1,200 cycle life, cheaper upfront (Rs 55,000–75,000 per 200Ah unit), heavier and bulkier. Best for budget installations with 4–6 hour backup.
LiFePO4 Lithium: 90% usable DoD, 4,000+ cycle life, Rs 70,000–75,000 per kWh. Lighter, longer warranty, and better long-term value. Ideal for heavy loads and 6–8 hour backup.

A 48V system is recommended for loads above 3 kW — it reduces cable losses and supports higher-capacity inverters available in the Pakistani market (Fronius, Solis, Growatt, InfiniSolar). Learn how solar and battery systems qualify as green energy sources with zero environmental impact.

Frequently Asked Questions

Why is a 20% safety buffer added to solar and inverter load calculations?

Inductive appliances like ACs, refrigerators, and water pumps draw 2–3x their running wattage during motor startup (surge inrush current). A 20% safety overhead prevents inverter overload trips and accounts for ambient temperature derating during Pakistani summer peak temperatures above 45°C.

What is the difference in solar requirements between Inverter and Non-Inverter ACs?

A conventional 1.5 Ton split AC draws 1,800W–2,200W continuously, requiring at least a 3.6 kW inverter and 4–5 solar panels per unit. A 1.5 Ton DC Inverter AC throttles its compressor speed, consuming 500W–1,200W once stabilized, drastically reducing battery drain and panel count.

How do I calculate battery backup Ah for load shedding?

Battery capacity = (Total Watts × Required Hours) ÷ (System Voltage × Depth of Discharge × 0.85 Efficiency). For tubular lead-acid batteries, DoD is 50%. LiFePO4 lithium batteries provide 85%–90% usable capacity. A 48V system is recommended for loads above 3 kW.

What is the difference between Day-Only and Day+Night solar system costs?

A Day-Only system relies on solar panels and a hybrid inverter to run appliances during sunshine hours, with net metering to export excess power. A Day+Night system adds a heavy tubular or lithium battery bank to power loads during nighttime load shedding, increasing the initial cost significantly.