Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
Home Battery Sizing Calculator
Size a home battery storage system to cover a specific backup load for a chosen number of days without grid or solar input, accounting for depth of discharge, round-trip efficiency, and a safety reserve.
Battery capacity needed
29.63 kWh
20-40 kWh needs two stacked units. At ~29 kWh you are sizing for about 2 days of autonomy on a 10 kWh/day load; trimming autonomy by a day cuts capacity nearly in half.
This is the rated battery capacity needed to cover your backup load after depth-of-discharge, efficiency, and reserve losses; a single Tesla Powerwall is about 13.5 kWh usable.
Solar Load Calculator
Calculate the total daily energy demand of your home's lighting, appliances, and HVAC to correctly size a solar system. Use this before getting solar quotes to know exactly how many kilowatt-hours per day you need to generate.
Key differences
| Home Battery Sizing Calculator | Solar Load Calculator | |
|---|---|---|
| Category | Solar Energy | Solar Energy |
| Inputs required | 5 | 5 |
| Result | Battery capacity needed (kWh) | Required Solar Capacity (kW) |
| What it does | Size a home battery storage system to cover a specific backup load for a chosen number of days without grid or solar input, accounting for depth of discharge, round-trip efficiency, and a safety reserve. | Calculate the total daily energy demand of your home's lighting, appliances, and HVAC to correctly size a solar system. Use this before getting solar quotes to know exactly how many kilowatt-hours per day you need to generate. |