The short answer
If your battery is too small for how you live now, out of warranty, or no longer supported by its maker, Canadian Solar’s EP Cube is a strong upgrade. It’s an all-in-one inverter and battery that supports both AC and DC coupling, so it can work alongside your existing solar inverter or take your panels directly. On a single-phase supply it grows from 5 to 20 kWh, with power-cut backup built in.
Plenty of homes now have solar with a battery that no longer fits. The house has changed, the battery hasn’t, or the company behind it has. Here’s how to tell if yours needs upgrading, why the EP Cube is the battery we reach for in that situation, what the job involves, and when it isn’t the right choice.
Signs your battery needs upgrading
- It’s empty by mid-evening. An electric car, a heat pump or working from home can outgrow a battery that was the right size a few years ago.
- It’s out of warranty, or close to it. If something fails after that, the repair is on you.
- Its maker no longer supports it. No warranty route, no app updates, no one to call.
- It does nothing in a power cut, and you’d like the house to keep running.
- It can’t keep up with your tariff, charging cheaply overnight and covering the peak.
One example of the third: GivEnergy Ltd went into administration in April 2026. Installed GivEnergy batteries carry on working, but if you own one and you’re unsure where you stand on warranty or support, it’s worth knowing your options before anything goes wrong. And if your battery is working well, is the right size and is still in warranty, there’s no need to change it.
Why the EP Cube suits an upgrade
It works with the solar you already have
This is the big one. Canadian Solar says the EP Cube works with existing solar systems and other brands’ inverters (AC coupling), or connects straight to your panels (DC coupling). So if your solar inverter is healthy, it can stay. If it’s old, the EP Cube’s own inverter can take your panels instead, up to 10 kW of them.
Start at the size you need, add more later
Storage comes in 5 kWh modules: 5, 10, 15 or 20 kWh on a single-phase supply. Each module weighs under 43 kg, and you can add more later as your usage grows. A three-phase version runs from 10 to 40 kWh.
Backup built in
The switchover is built into the EP Cube’s inverter: in a power cut it takes over automatically and can power the house up to 7.6 kW. If severe weather is forecast, it charges to full in advance so you’re ready.
A long battery warranty
The inverter has 10 years. The battery has up to 15 years or 6,000 cycles, whichever comes first, so a battery that cycles once a day is well within it.
Smart without the fuss
The EP Cube App lets you set it up around your tariff’s cheap and peak times, watch your solar and usage live, and switch devices on or off automatically depending on how much is stored. Its energy manager also works with heat pumps and EV chargers.
Inside or out
The modules are IP67 and the whole system IP65, and it runs from minus 20 °C to 50 °C. It only charges above 0 °C, so a garage or sheltered wall beats an exposed spot. It stands on the floor or mounts on the wall.
EP Cube at a glance
What it is
EP Cube: An all-in-one hybrid inverter and battery in one tower
How it joins your solar
EP Cube: AC coupling alongside your existing inverter, or DC coupling straight to your panels
Storage
EP Cube: 5, 10, 15 or 20 kWh, in 5 kWh modules
Power output
EP Cube: Up to 7.3 kW continuous (less with one or two modules)
Solar input
EP Cube: Up to 10 kW of panels, two MPPT inputs
Power-cut backup
EP Cube: Built in and automatic, up to 7.6 kW
Warranty
EP Cube: Inverter 10 years; battery up to 15 years or 6,000 cycles, whichever comes first
Indoors or outdoors
EP Cube: Either: modules IP67, whole system IP65
Temperature
EP Cube: Runs from minus 20 °C to 50 °C, charges from 0 °C
Mounting
EP Cube: Floor standing, or on the wall
App
EP Cube: EP Cube App: tariff settings, live monitoring, storm preparation
From Canadian Solar’s UK product pages and its June 2026 single-phase datasheet. We confirm the exact model and warranty in your quote.
What the upgrade involves
- Tell us what you have. A photo of your inverter and current battery, roughly what you use, and whether you’re on the Feed-in Tariff or the Smart Export Guarantee.
- Free remote survey and design. We design the system in OpenSolar, then our technical solar designer talks it through with you on a video call.
- We check your inverter. Its make, model and age decide whether the EP Cube joins alongside it or takes over your panels.
- We plan what happens to the old battery, and confirm your price after the survey.
- We notify the network operator. Adding storage changes what your home can export, so the DNO needs to know. We handle it.
- Install day. Adding a battery to an existing system is usually done in a day.
If you’re on the older Feed-in Tariff, tell us at the start: we design the battery so it doesn’t affect how your generation meter reads. A battery added to existing panels is 0% VAT until 31 March 2027. More on the process: adding or upgrading a battery on existing solar.
Who the EP Cube isn’t right for
- You want EV charging built into the battery. Sigenergy SigenStor has a DC charging module that slots into the stack.
- You need more than 20 kWh on a single-phase supply. Sigenergy (about 54 kWh per stack) and EcoFlow (up to 48 kWh per inverter) go further.
- You want the lowest possible cost. Hanchu is our lowest-cost route into storage.
- You don’t have solar panels. We add batteries to solar systems, not on their own.
- Your current battery is fine. Then keep it.
See how it compares with the rest: every battery we fit.
Our verdict
For a home that already has solar and a battery that’s too small, too old or unsupported, the EP Cube is a sensible, flexible upgrade: it fits around the system you have, backs up the house in a power cut, and grows with you. Our technical solar designer can look at your current set-up and show you on a video call whether the EP Cube, or something else, is the right fit.
Full details: Canadian Solar EP Cube.
