DIY Powerwall Calculator & Solar System Planner

Figure out a rough baseline for a DIY powerwall system with storage, inverter, and solar recommendations.

Plan the system before you buy the hardware

Enter your daily usage, outage window, and generation preferences to get storage, solar, and inverter recommendations sized for your situation. Start with realistic numbers and iterate from there.

What this planner covers

  • Solar system planning and size requirements
  • Total power you need to store in battery storage
  • How much power you need to generate with your solar system
  • How big of a battery you need to store all of the power
  • How much power you can generate in your zip code based on historical weather data
  • A done-for-you system complete with specific inverters, solar charge controllers, battery packs, and solar panels
Start from a common scenario

US zip codes only for now. Outside the US, use a zip code with similar climate for a rough estimate.

DIY Powerwall FAQ

How big should my powerwall be?

Size it to your daily energy use in kilowatt-hours times the days of backup you want. A home using 30kWh per day that wants one day of autonomy needs roughly 30kWh of usable storage; lithium is usually sized so you use about 80 to 90 percent of its rated capacity.

How much solar do I need?

Enough to replace your daily consumption plus charging losses within your location's peak sun hours. The planner estimates sun hours from your ZIP code and sizes the array to recharge the battery each day.

What inverter size do I need?

Size the inverter to your peak simultaneous load, including motor start-up surges, not your average draw. A home running a well pump and air conditioner together can peak well above its average power.

What battery voltage should a powerwall use?

Higher-voltage banks carry less current for the same power, which means thinner wiring and lower losses. 48V is the standard for whole-home DIY powerwalls; 12V and 24V suit smaller systems.

Can I use this for an off-grid system?

Yes. The planner sizes for off-grid or backup use. Off-grid needs more days of autonomy and extra solar headroom to ride through cloudy stretches.

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