Very accurate when you enter your monthly kWh from a real bill — we use real sun-hour data from the NREL TMY3 dataset and current utility rates from the EIA. Without a bill, we use regional household averages, which are within ~15% for most homes. A BigBattery engineer reviews every quote before you commit.

The ESS price covers the hybrid inverter, battery modules, BMS, and stackable enclosure — everything BigBattery ships and warranties. Install (mounting, conduit, electrical tie-in) is performed by a licensed electrician you hire locally and is not included in the price shown here.

No — BigBattery sells the ESS (battery + inverter), not solar panels. Panels are typically sourced through your local installer, and pricing varies by region and brand. We size and recommend the matching panel array (how many panels, what total kW) so your installer can quote panels that pair cleanly with your inverter's max solar input.

Many of our customers do partial DIY (battery and inverter) and hire a licensed electrician for the grid tie-in. Our kits are designed for both DIY and professional install. We provide full documentation and phone support during your install.

Easy — the EG4 PowerPro ESS is fully expandable. Add additional battery modules anytime to grow your storage. A BigBattery engineer will verify your sizing before purchase.

BigBattery LiFePO4 battery modules carry a 12-year warranty. Hybrid inverters carry a 10-year warranty. Solar panels (sourced separately) typically carry a 25-year production warranty from the panel manufacturer.