Add Battery Backup to
your existing solar.
Battery Retrofit for Existing Solar · Edmonton & Area
Your panels make the power. Now keep it when the grid drops. The AC-coupled EP Cube retrofits onto virtually any grid-tied solar system — ours or another installer's — and takes over your home in under 20 milliseconds. One day on site, installed by our in-house Red Seal Master Electrician.
What adding a battery to existing solar costs.
An AC-coupled EP Cube retrofits onto virtually any existing grid-tied solar system in the Edmonton region — regardless of who installed it — for $19,381 (9.9 kWh) to $24,723 (19.9 kWh) all-in. Your panels keep running exactly as before, the on-site install takes one day, and switchover is automatic in under 20 milliseconds.
AC-coupled, in plain language.
The EP Cube has its own hybrid inverter built in, and it couples on the AC side of your electrical panel — downstream of whatever your solar already uses. That's why it doesn't care whose equipment is on your roof. Your array keeps producing, exporting and earning credits exactly as it does today; the battery simply sits between your panel and the loads you want protected. When the grid drops, it forms its own backup circuit for your home while CEC anti-islanding rules keep the grid side dead — so utility line crews stay safe, and rapid shutdown per Rule 64-218 still applies where required.
Microinverter systems
Systems built on microinverters — like the APsystems DS3 units Stellar installs — are AC on the roof already, which makes them a natural fit. The EP Cube couples at the panel and your microinverters never know the difference.
String-inverter systems
A string inverter from another installer — any mainstream brand, any age — works too. Nothing on your roof or your existing inverter gets replaced or rewired. We verify the model and AC output at the free assessment.
Safe by design
In an outage the EP Cube island-forms a backup circuit for your house in under 20 milliseconds, while anti-islanding protection guarantees nothing feeds back into downed lines. Code-first, inspected, and permitted — every time.
Every EP Cube size, priced all-in.
Same fixed retrofit pricing across Edmonton, Sherwood Park, St. Albert, Spruce Grove, Leduc, Beaumont and Fort Saskatchewan. Every price includes the EP Cube battery, its built-in hybrid inverter, installation by our Master Electrician–led crew, engineering, and your municipal electrical permit and inspection. No trip charge, no hidden line items.
| EP Cube 1.0 size | Typical retrofit fit | Runtime @ ~10 kWh/day critical loads | Installed price (all-in) |
|---|---|---|---|
| 9.9 kWh | Essentials: fridge, freezer, furnace fan, lights, Wi-Fi | ~24 hours | $19,381 |
| 13.3 kWh | Essentials plus sump pump and extra margin | ~32 hours | $21,578 |
| 16.6 kWh | Larger homes and mid-size arrays (8–10 kW) | ~40 hours | $22,942 |
| 19.9 kWh | Whole-home priority loads, max solar self-consumption | ~48 hours | $24,723 |
Straight talk on the bundle discount: the $1,000 off applies only when a battery is bundled with a new Stellar solar install — it does not apply to battery-only retrofits on existing systems. What retrofit customers do get: refer a neighbour who books a battery backup install and receive a flat $500 through our referral program. Modular 3.3 kWh modules mean any unit can be expanded later, up to 19.9 kWh, and the new EP Cube 2.0 (5–40 kWh modular) is available on consultation pricing. No battery rebates exist in Alberta in 2026. Full pricing breakdown →
$0-down financing through Financeit at the standard 7.99% rate (2026). Pre-qualify in minutes →
How long each size runs your house.
All four sizes deliver 7.6 kW of continuous output — enough to run your fridge, freezer, furnace fan, lights, sump pump and Wi-Fi at the same time. Capacity decides how long they keep running — and with your existing array recharging the battery every day, daylight resets the clock.
| What's running | Draw | 9.9 kWh | 13.3 kWh | 16.6 kWh | 19.9 kWh |
|---|---|---|---|---|---|
| Fridge + freezer only | 150W | ~66 hrs | ~88 hrs | ~110 hrs | ~132 hrs |
| Furnace fan | 500W | ~20 hrs | ~26 hrs | ~33 hrs | ~40 hrs |
| Critical loads bundle* | ~10 kWh/day | ~24 hrs | ~32 hrs | ~40 hrs | ~48 hrs |
*Critical loads = fridge, freezer, furnace fan, lights, sump pump, Wi-Fi and phone charging, running simultaneously. Actual runtime varies with usage. Because your solar recharges the battery whenever the sun is up, outage coverage on a solar home is effectively open-ended.
Your panels already shut off in an outage. That's the gap.
Here's the part most solar owners only learn during their first blackout: a grid-tied system without a battery must disconnect when the grid fails — anti-islanding is the law, and it protects line crews. Sunny day, panels on the roof, house dark anyway. A battery is the missing piece that lets your solar keep working when it matters most. And Alberta's grid has already rehearsed the argument: on January 13, 2024, the AESO declared a grid alert and a province-wide emergency alert hit every phone at 6:44 p.m.; on April 5, 2024, actual rotating outages shed about 244 MW of load between 8:53 and 9:16 a.m.
The blackout blind spot
No battery means no solar during an outage — your inverter is required to shut down. With an EP Cube, the system island-forms in under 20 milliseconds and your array keeps charging the battery through the blackout.
Rare, short — unannounced
EPCOR's Edmonton customers averaged 0.58 hours of outage in 2023; FortisAlberta customers average under 1.3 hours a year. Outages here are rare and short, but never scheduled — which is exactly the case for instant, hands-off switchover.
Honest Alberta math
Alberta has no residential time-of-use rates, so a battery here is resilience plus solar self-consumption — not rate arbitrage. We won't tell you a battery lowers your bill by itself, because in Alberta it doesn't.
We installed your solar? Your homework is already done.
If Stellar installed your system, we still have your design file: array size, inverter details, panel schedule, service capacity, roof layout, site photos. That makes the retrofit assessment fast — usually a short visit to confirm the garage wall and which circuits you want protected, then straight to engineering. Same crew, same in-house Red Seal Master Electrician, same posted pricing you saw the first time.
Installed by someone else? Welcome too. Bring a photo of your inverter or microinverter setup and your electrical panel, and we'll take it from there. We retrofit systems from any installer — including companies that are no longer around to answer the phone. The EP Cube doesn't care whose sticker is on the roof.
“Our solar was installed four years ago by a different company. When we asked them about adding battery backup, they said they couldn’t figure out the integration. Stellar got it done. The EP Cube ties into our existing solar and our Generac standby, and the system manages itself — solar by day, battery at night, generator as final backup. We don’t worry about outages anymore.”
Installed by our Red Seal Master Electrician and the Stellar Upgrades team — 550+ installs completed since 2018.
Three things to know before you sign anything.
The capacity cap
Alberta's electrical code (CEC Rule 64-918) caps home battery storage at 20 kWh per unit and 40 kWh per dwelling — in practice, up to two EP Cubes for about 39.8 kWh. For almost every solar home, one right-sized unit is plenty.
Where it mounts
On the wall of your attached garage in most homes — the standard location under Alberta STANDATA Variance 21-ECV-064-900-ESS. The NEMA 4X-rated EP Cube handles garage conditions fine, and basements are prohibited for battery storage.
What changes on your bill
Nothing, by itself — Alberta has no time-of-use rates to arbitrage. Your exports and credits continue as before; the battery adds backup and shifts more of your own solar into your own evening use. That's the honest pitch.
Four steps. Typically 4–6 weeks.
Free assessment
We confirm your existing inverter or microinverters, panel capacity and garage wall, walk through which circuits you want backed up, and give you an exact all-in price. Fast if we installed your solar — we already have the file.
Engineering & permit
Our team prepares the drawings and our in-house Red Seal Master Electrician pulls the electrical permit with your actual authority — City of Edmonton, Strathcona County, City of St. Albert, Spruce Grove, Leduc, Beaumont or Fort Saskatchewan.
One-day install
Mount, wire, tie into your panel, configure the automatic switchover and your self-consumption settings. The on-site install is one day, and battery-only retrofits don't require a meter swap.
Inspection & commissioning
Municipal inspection, commissioning, and EP Cube app setup on your phone. Typical timeline from signed agreement to a commissioned battery: 4–6 weeks.
A Red Seal Master Electrician on every permit.
A battery retrofit ties into your main electrical panel and reconfigures how your home takes power — so it legally requires an electrical permit pulled by a licensed electrical contractor. Stellar's in-house Red Seal Master Electrician is named on every permit we pull, in every municipality we work in. We never subcontract: the crew that quotes your retrofit is the crew that installs it.
In-house, on payroll
Certified electricians supervised by our Master Electrician of record. No subcontractors on any residential install, ever.
$5M insured · BBB A+
Fully insured with $5M general liability, BBB A+ accredited, and operating since 2018 with the same Master Electrician on every permit.
Code-first installs
Attached-garage mounting per Alberta STANDATA Variance 21-ECV-064-900-ESS, capacity per CEC Rule 64-918, NEMA 4X-rated hardware, 10-year / 6,000-cycle warranty from Canadian Solar.
Asked by solar owners.
Finish what your solar started.
Free assessment, exact all-in price before you commit, and a commissioned battery typically 4–6 weeks after you sign — one day on site.
$0-down financing available · Pre-qualification won't affect your credit score
More on home batteries in Alberta.
Battery backup by community: Sherwood Park · St. Albert · Spruce Grove · Leduc · Beaumont · Fort Saskatchewan
Not ready for a form? Text us.
Text your address to (780) 200-5265 and we'll reply with a ballpark retrofit quote — usually within the hour.
Text for Quick Quote →Keep the power your panels make.
We confirm your existing system, plan the switchover wiring, and give you an exact all-in price. No obligation. 20 minutes.
Free assessment includes a check of your existing inverter and electrical panel, backed-up circuit planning, EP Cube sizing for your actual loads, and a firm installed price with no obligation.
- Free assessment — no obligation
- Works with any installer's solar system
- $0 down financing
- Master electricians — no subcontractors
- Municipal permit & inspection handled
"Our solar was installed four years ago by a different company. When we asked them about adding battery backup, they said they couldn’t figure out the integration. Stellar got it done."