How to choose a solar inverter in Pakistan
The single most common mistake we see on Hall Road is a customer who bought an inverter that is too small for his load. Here is how to size it properly.
1. Add up what you actually run at the same time
List the appliances that run together and their watts. Typical Pakistani home numbers: ceiling fan ~80W, LED bulb ~12W, 32" LED TV ~60W, WiFi router ~12W, inverter fridge ~150W.
The running total decides your inverter size. Motors (fridge, pump) also draw 3-7x that for a second at startup, so add about 25% headroom.
2. Pick the inverter size
| If you run together… | Buy |
|---|---|
| 4 fans + 8 LEDs + TV | 1200-2000W |
| The above + fridge | 3000W |
| Plus a 1-ton inverter AC | 5000W+ |
Choose pure sine wave for anything with a motor or compressor — see pure vs modified sine wave.
3. Size the battery for your backup hours
Daily energy (Wh) = total watts × hours. For a 12V bank, Ah ≈ (Wh ÷ 12) × 2 (never discharge lead-acid below 50%). Example: 600Wh/day → ~100Ah; a full night of fans+lights usually wants 200Ah+.
4. Size the panels to refill the battery
Panel watts ≈ (daily Wh ÷ peak sun hours) × 1.25. Punjab gets ~5.4 peak sun hours, so 1000Wh/day ≈ 230W of panel — but most homes fit 2-4 × 550W panels to also offset the grid.
5. Use an MPPT controller
An MPPT controller (like the Simtek Planet40 40A MPPT) harvests 20-30% more from the same panels than a PWM unit, and can take higher panel voltage.