When you invest in solar panels and battery storage, the questions are always the same. How much electricity will it actually generate. How much difference does the battery make. Is there any maintenance or hassle involved. And above all, how much impact will it really have on your electricity bill. Is it a worthwhile investment.
Back in January 2025, Spirit Energy began offering the Sigenergy SigenStor in the UK. The first installations were completed in April, and now six months on we can look back at how the system has performed, what has changed in the product line, and whether it has lived up to expectations.
It’s also worth noting that Sigenergy has quickly become one of the leading alternatives to Tesla Powerwall 3. So let’s open up the details and take a look.
The Setup
SigenStor is a modular battery system that stacks neatly on top of itself. At the top sits the energy controller, which combines the inverter, battery management, and solar controls. Below that sit the battery modules, available in different capacities, and in some cases an EV DC charger which can replace one of the modules if required.
A single stack can take up to six modules beneath the controller. With the release of new sizes in June and July, the options now include:
- 5 kWh and 8 kWh modules (launched initially).
- 6 kWh and 10 kWh modules (added mid‑2025).
It’s worth noting that the 10 kWh module has 9 kWh of usable storage, which is fairly typical across the industry where a buffer is reserved to protect the cells.
Solar and Battery Performance
The inverters range from 3 kW to 12 kW and include between 2 and 4 MPPTs, depending on the model. This makes them flexible for different roof shapes and for dealing with shading without the need for microinverters.
The batteries charge and discharge at roughly half their rated capacity per module. For example, a 10 kWh module will charge and discharge at up to 5 kW, and multiple modules add together before being capped by the inverter’s rating.
In day‑to‑day use, households typically see:
- Direct solar generation used in the home.
- Surplus solar stored in the battery.
- Smart off‑peak charging at cheap rates to reduce bills further.
Combined Performance
Sigenergy systems can be set up in different modes. Self‑consumption mode prioritises filling the battery with solar to maximise grid independence. Time‑of‑use mode focuses on working with your tariff to save money, for example charging at cheap night‑time rates and exporting solar during peak times when rates are high.
This flexibility means savings can be maximised, even if full grid independence isn’t the main goal. Many UK households on tariffs like Octopus Agile or Go find this especially useful.
Backup and Reliability
For power cut protection, the Sigenergy Gateway can be added. This device isolates the house from the grid during an outage and allows the battery to keep running. It supports a full 100‑amp single‑phase supply, with options to split critical and non‑critical loads. In practice, the switchover is fast enough that most people won’t even notice when the power goes down.
Over the first six months in the UK, installs have been stable. The app is straightforward, and most issues can be diagnosed remotely. No major reliability problems have emerged so far.
Living With the System
Once installed, SigenStor is very much “fit and forget”. After commissioning and tariff setup, it runs automatically. The app shows solar generation, battery status, grid import/export, and household consumption. Updates are every ten seconds, which is quick enough for everyday monitoring.
The modular design also means systems can be expanded later, and the new 6 kWh and 10 kWh modules can be added to older stacks without replacing the controller.
Warranty and Safety
Sigenergy batteries come with 10 year or throughput warranty [depending on battery size], whichever occurs first. The DC EV charger, available as a 12.5 kW or 25 kW module, comes with a 3-year warranty, and the gateway is covered for 5* years.
Each battery module is built with multiple safety features, including thermal monitoring, insulation pads, a decompression valve, and even a built-in fire suppression system. That level of engineering gives homeowners added reassurance.
Six‑Month Verdict
Six months on, the Sigenergy SigenStor has proven to be a strong contender in the UK battery market. It is modular, easy to install, and flexible to design. The app is well thought out, the tariff integration works well with dynamic rates, and the future‑proofing of the system gives households the ability to expand later.
For those who want a premium, non‑Tesla option for home storage, Sigenergy is already showing itself to be an excellent choice.
If you’d like to know how much you could save with solar and battery storage, or to get a tailored SigenStor quotation, please get in touch with our team.
