Whole-Home Battery Backup in Ontario: EG4 vs EP Cube 2.0 (2026 Buyer's Guide)

What Is a Whole-Home Battery Backup System?

A whole-home battery backup system stores energy from the grid or from solar panels and automatically powers your home when the grid goes down. Unlike a portable power station, it is wired into your electrical panel and takes over without extension cords or manual switching.

A good system does two jobs. It keeps the lights, the furnace, the fridge and the sump pump running in an outage, and on Ontario's time-of-use or Ultra-Low Overnight rates it can charge on cheap overnight power and run your home through the expensive on-peak hours.

System 1: EG4 Hybrid Inverter + GridBOSS

EG4's whole-home system pairs a hybrid inverter (the 18kPV or the FlexBOSS18) with the EG4 GridBOSS and one or more EG4 14.3 kWh LiFePO4 batteries.

• Power: the 18kPV delivers up to 12 kW of AC power with solar, and the FlexBOSS18 up to 13 kW. Both accept up to 18 kW of solar.
• Capacity: 14.3 kWh per battery. Two batteries give you 28.6 kWh, three give you 42.9 kWh, and you can add more later.
• Generator and big loads: the GridBOSS manages a backup generator and can shed or control large loads, which helps the battery last through a multi-day outage.
• Warranty: 10 years on the batteries and 10 years on the hybrid inverter.
• Best for: larger homes, farms and rural properties, homes with high loads such as electric heat or a well pump, and anyone who wants room to grow.

System 2: Canadian Solar EP Cube 2.0

The EP Cube 2.0 is an all-in-one unit: the hybrid inverter and the batteries stack together in one slim cabinet.

• Power: up to 11.5 kW of AC power.
• Capacity: 5 kWh battery modules, from 5 kWh up to 40 kWh per unit, and up to 120 kWh with multiple units.
• Whole-home transfer: the EP Cube Smart Gateway switches your whole home to battery power automatically, with black start capability.
• Solar: six solar inputs, which suits roofs with panels facing several directions.
• Extras: works with backup generators and supports Level 2 EV chargers, with a clean, simple app.
• Warranty: 10 years or 6,000 cycles, with at least 80% capacity retained.
• Best for: homeowners who want a tidy, modern-looking system on the wall, flexible sizing in smaller steps, and solar on a complicated roof.

Side by Side

Where Does the Battery Go?

Both systems are rated for outdoor installation, and outside on an exterior wall is our default for both. It keeps the battery out of your living space and allows more total storage under the Ontario Electrical Safety Code (up to 80 kWh outdoors or in a garage).

If the battery goes inside, it needs a dedicated room with a fire-rated, self-closing door, drywall and a smoke alarm, and the room cannot open into a bedroom. We confirm placement at the site visit, before you commit.

Already Have Solar?

If you already have solar panels, we do not bolt a second system onto your old one. We remove the existing solar inverter and connect your panels directly into the new EG4 or EP Cube 2.0 unit, so you end up with one system, one app and one warranty.

Rebates: Up to $10,000

Both EG4 and EP Cube 2.0 qualify for Ontario's Home Renovation Savings rebate when they are installed together with new rooftop solar as a non-exporting system: $1,000 per kW of solar (up to $5,000) and $300 per kWh of battery (up to $5,000). A battery on its own does not qualify. Read our full rebate guide for the details.

Which One Should You Choose?

Choose EG4 if you have a larger home or higher loads, want the most battery for the budget, or want the flexibility to go further off the grid later.

Choose EP Cube 2.0 if you want a clean all-in-one look, sizing in smaller 5 kWh steps, or have a roof with panels facing several directions.

TRU Off Grid installs both, so we can recommend the one that fits your home rather than the one we happen to sell. Call Jacob Collier at 647-914-9699 or email jacob@truoffgrid.com, and send us a recent hydro bill for a free system design.