Should I add a battery to my solar system?

A battery makes financial sense when there is a significant difference between peak and off-peak electricity rates (like Ontario's ULO plan with 3.9¢ overnight vs. 39.1¢ peak). Batteries also provide backup power during outages. The decision depends on your rate structure, consumption patterns, and whether you value energy independence.

How much does a solar battery cost in Canada?

Solar batteries in Canada range from $8,000 for a 16 kWh Renon system to $17,000 for a Tesla Powerwall (13.5 kWh). After Ontario's battery rebate (up to $5,000), net costs can be significantly lower. The cost per usable kWh typically ranges from $400-$1,000 after rebates.

How long do solar batteries last?

Most solar batteries come with 10-year warranties and are rated for 3,650-6,000 cycles. With daily cycling, a quality battery should last 10-15 years. Lithium iron phosphate (LFP) batteries tend to last longer than other lithium-ion chemistries.

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Solar Panels vs Battery Storage

Should you get solar panels, a battery, or both? Compare costs, ROI, and functionality to make the right decision for your home.

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Side-by-Side Comparison

Feature	Solar Panels	Battery Storage
Primary Function	Generate electricity from sunlight	Store electricity for later use
Cost Range	$21,000 – $48,000 (6-15 kW)	$8,000 – $17,000 (10-32 kWh)
Payback Period	8-14 years	7-12 years (with TOU arbitrage)
Lifespan	25-30 years	10-15 years (3,650-6,000 cycles)
Maintenance	Minimal — occasional cleaning	Minimal — firmware updates
Best For	Offsetting electricity consumption	Peak shaving, backup power, TOU arbitrage
Works Without Grid?	No (grid-tied systems shut off)	Yes — provides backup power
Ontario Rebate	Up to $5,000 (HRS)	Up to $5,000 (HRS)
Space Required	Roof space (24 sq ft per panel)	Wall/floor space (3-6 sq ft)

When Should You Add a Battery?

Strong case for a battery:

You're on Ontario's ULO rate plan (3.9¢ vs 39.1¢ peak = 10x arbitrage)
You want backup power during grid outages
Your utility has significant TOU rate differentials
You have a zero-export system and want to maximize self-consumption

Battery may not be needed if:

You're on a flat rate with no TOU differential
You have net metering with full retail credit
Your budget is limited — solar alone provides better ROI
Your electricity rates are low (e.g., Quebec at 7.3¢/kWh)

Peak Shaving Explained

Peak shaving is the strategy of using battery storage to avoid purchasing electricity during the most expensive rate periods. Here's how it works with Ontario's ULO rate plan:

Charge: Battery charges overnight at 3.9¢/kWh (11 PM – 7 AM)

Hold: Battery holds charge during mid-peak hours

Discharge: Battery discharges during on-peak at 39.1¢/kWh (4–9 PM)

Savings: Each kWh shifted saves 35.2¢ (39.1¢ − 3.9¢)

A 16 kWh battery with 14.4 kWh usable capacity, cycling daily during peak hours, can save approximately $1,800-$2,200 per year through peak shaving alone — before accounting for solar production.

Compare Solar + Battery Options for Your Home

Our calculator models solar-only, battery-only, and combined systems to show you the optimal configuration.

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Solar Panels vs Battery Storage

Side-by-Side Comparison

When Should You Add a Battery?

Strong case for a battery:

Battery may not be needed if:

Peak Shaving Explained

Compare Solar + Battery Options for Your Home

Frequently Asked Questions

Related Resources

Best Solar Batteries Canada

Best Solar Panels Canada

TOU vs ULO Ontario

Peak Shaving Calculator

Solar Panel Cost

Solar Calculator