Battery & Backup Calculators

Home battery systems serve two main purposes: storing excess solar energy for later use and providing backup power during grid outages. The right battery size depends on which of these goals matters most to you — and the answer affects both capacity requirements and total cost significantly.

Start with the battery sizer to determine the right capacity in kWh based on your daily energy patterns. Then check how long that battery would last during an actual outage with the backup time calculator — the gap between "enough for daily cycling" and "enough for a multi-day outage" is often larger than people expect.

If you're weighing a battery against a traditional generator, the generator vs battery comparison breaks down total ownership cost over 10-20 years including fuel, maintenance, and replacement. The whole-home vs essential-loads calculator shows how limiting backup to critical circuits can cut battery requirements (and cost) dramatically. For long-term planning, the degradation modeler projects how capacity declines over years of use across different battery chemistries, while the blackout readiness tool stress-tests your setup against 1-day, 3-day, and 7-day outage scenarios.