Batteries & Backup: How Many kWh Do I Need?

Home batteries store electricity for later use. They keep essentials running during blackouts, reduce peak-hour costs, and increase energy independence.

Why Add a Battery?

A solar battery lets you use your own power at night or during outages instead of buying from the grid. It provides backup power and maximizes self-consumption of solar energy.

When Does It Make Sense?

• Frequent power outages in your area
• Utilities with time-of-use pricing (evening rates are higher)
• Limited or no full-rate net metering
• Desire for more energy independence

Sizing Guide (Approximate)

• 10 kWh: Basic backup (fridge, lights, Wi-Fi for several hours)
• 20–30 kWh: Whole-home evening use or time-of-use optimization
• 80+ kWh: Off-grid living for multi-day independence

The average U.S. home uses ~30 kWh per day, so a single 10–15 kWh battery typically covers essentials for one day. Larger homes or electric heating may need more.

Tip

Start with one battery and expand later. Most systems are modular, so capacity can grow with your needs.