🌞 Want to keep your fridge running during blackouts or go off-grid? This guide breaks down exactly how many solar panels and batteries you’ll need – with real-world examples.
🚀 Quick Answer
Most refrigerators need:
- 300-600W solar panels
- 100-200Ah battery bank
- Example: A standard 18 cu. ft. fridge running 8 hours/day needs about 400W solar + 200Ah lithium battery.
🧮 Solar Sizing Calculator (We’ll add this link later)
| Fridge Size | Solar Needed | Battery Backup | Runtime (No Sun) |
|---|---|---|---|
| Mini (4.5 cu. ft.) | 200W | 100Ah Lithium | 12 hours |
| Standard (18 cu. ft.) | 400W | 200Ah Lithium | 24 hours |
❄️ Fridge Power Basics
All fridges have:
- Running watts (continuous power)
- Surge watts (3-8x higher at startup)
Pro Tip: Older fridges (pre-2001) use 2-3x more power! Consider upgrading to an EnergyStar model.
⚡ Solar Calculation Formula
### ✏️ Calculate Your Exact Needs 1. Find fridge wattage (use a [Kill-A-Watt meter](https://amzn.to/3…)) 2. Daily watt-hours = Watts × Hours used 3. Add 30% buffer: ___ Wh × 1.3 = ___ Wh 4. Solar needed = (Daily Wh ÷ Peak sun hours) (Daily kWh × 1,000) ÷ Peak Sun Hours = Solar Watts NeededExample Calculation:
- Fridge: 150W running × 8 hours = 1.2kWh daily
- Account for 30% system losses: 1.2kWh × 1.3 = 1.56kWh
- Divide by peak sun (4 hours): 1,560Wh ÷ 4h = 390W solar needed
🔋 Battery Sizing Guide
- Lithium (LiFePO4): 100Ah runs 100W fridge for ~10 hours
- Lead-Acid: Double the capacity (50% depth of discharge)
Learn more: Battery Types Compared
💰 Real-World Setup Examples
| Scenario | Solar Needed | Battery | Cost Estimate |
|---|---|---|---|
| Home Fridge (18 cu. ft.) | 400W | 200Ah LiFePO4 | $1,200-$1,800 |
| RV Fridge (12V) | 200W | 100Ah Lithium | $600-$900 |
Prices before solar tax credits.
Can I run a fridge directly from solar panels without batteries?
Only with grid-tied systems (they use the grid as a “battery”). For off-grid setups, batteries are essential. Learn more in our Grid-Tied vs. Off-Grid comparison.
How do I find my fridge’s exact wattage?
Three methods:
- Check the nameplate sticker inside the fridge
- Use a Kill-A-Watt meter ($25)
- Look up your model on EnergyStar’s database
| Fridge Type | Running Watts | Surge Watts | Daily kWh (8h) |
|---|---|---|---|
| Standard 18 cu. ft. (new) | 120-150W | 900-1,200W | 1.0-1.2kWh |
| Mini Fridge (4.5 cu. ft.) | 50-80W | 300-500W | 0.4-0.6kWh |
| 12V RV Fridge | 40-60W | 200-300W | 0.3-0.5kWh |
