Sigenergy SigenStor review: the stackable battery aiming at Tesla

Quick answer: The SigenStor is the most convincing Powerwall rival yet to reach the UK. Stackable modules build systems up to about 48kWh, backup switchover is instant, and installed prices start around £4,500 to £6,000 for smaller systems, with 13kWh from £6,995. The catch is the maker’s age: Sigenergy was founded in 2022.

We haven’t tested this system. This review is based on published specifications, installer price guides and warranty documents, checked 1 August 2026.

What is the SigenStor?

Sigenergy calls it a 5-in-1: hybrid solar inverter, battery power conversion, energy management system, stackable battery modules and an optional DC EV charger, all in one floor-standing tower. It replaces the usual wallful of separate boxes with a single modular stack. Modules clip together, so a system can start small and grow.

The company is young, founded in 2022 by former industry executives, and it has moved fast into UK distribution. Fast-growing and new cuts both ways, and we’ll come back to that.

Practically, this is a floor-standing tower rather than a wall box, so you need floor space in a garage, utility room or outside; the IP66 rating means outdoor siting is fine. One softer criticism from Heatable’s review: the app works, but its polish trails Tesla’s, which matters if you enjoy watching your energy flows as much as some owners do.

SigenStor specs at a glance

Figures compiled from Ecoaim, Solar4Good and Heatable. One honesty note: UK installer sites don’t agree on the exact module ratings. Most list roughly 5.2kWh and 8kWh modules; some quote 6kWh and 9kWh, and quoted maximum stacks range from 48kWh to 54kWh. Sigenergy doesn’t publish a simple UK consumer price list either, so confirm the exact module rating and capacity on your written quote. 10,000+ rated cycles at full depth of discharge is as strong as any residential spec sheet we’ve reviewed.

What does it cost in the UK?

Solar4Good’s installed pricing runs £4,500 to £6,000 for 5-10kWh systems and £5,000 to £7,500 for 10-20kWh, with a maxed-out 54kWh build from £21,000. Heatable lists 13kWh from £6,995 installed. The DC EV charging module adds £3,500 to £4,000, and a backup-protected 18kWh configuration starts around £9,600.

At £6,995 for 13kWh, you’re paying about £538 per usable kWh installed, against £547 to £666 for a Powerwall 3 at typical installed prices. So it’s Powerwall money or slightly less, with capacity choice the Powerwall doesn’t offer. Work out what capacity you actually need with our battery sizing guide before anyone quotes you a tower of modules.

What about the warranty?

Ten years is the standard cover. Beyond that it gets murky. Published warranty terms differ between UK sellers: one lists 70% capacity retention at year ten, another lists 60% and 3,500 warranted cycles. Heatable also notes just 3 years on the EV charger module. Those aren’t small differences, so get the actual warranty schedule in writing and read the retention figure before you sign.

There’s also history to note: Sigenergy ran a recall in Australia in 2025, resolved with free replacement hardware and extended warranties according to Solar4Good. Not disqualifying, but worth knowing. And any 10-year warranty depends on the company existing in year nine; our guide to battery warranties when a manufacturer goes bust explains what GivEnergy’s collapse taught UK owners about that risk.

SigenStor or Powerwall 3?

On paper, the SigenStor wins. Capacity choice against one fixed 13.5kWh size. Built-in 0ms backup against a separate Gateway. A bi-directional DC EV charging option that Tesla’s home products don’t match. Similar or lower price per kWh.

What Tesla still offers is a decade of UK track record, a huge installer base and a battery your estate agent has heard of. If you keep a house for 15 years, that maturity has real value. Read our Powerwall 3 review and the full home battery comparison before deciding.

Should you buy one?

If you’re an EV household planning a bigger system, yes, the SigenStor belongs at the top of your shortlist. The modularity suits homes whose consumption is still growing, and the hardware pairs well with smart tariffs; see our guide to the best smart tariffs for solar and battery. If you want maximum certainty from a 10-year purchase, the four-year-old brand is the one real argument against it. That’s a judgement call only you can make.

FAQs

Is Sigenergy still trading?

Yes. We checked for administration or insolvency news on 1 August 2026 and found none; the company is expanding its UK installer network. It remains a young business, which is why we bang on about reading the warranty schedule.

Can the SigenStor charge an EV directly?

Yes, with the optional DC charging module (£3,500 to £4,000). It can charge the car from solar or battery, and charging is bi-directional, so the car can work as an extra battery for the house. Capabilities like that are still evolving; our virtual power plants explainer covers where this is heading.

How big can a SigenStor system go?

A single tower stacks to roughly 48kWh on most sellers’ figures (one lists 54kWh), and installers quote multi-tower setups beyond that. For context, a typical UK home draws 7-10kWh a day, so even one full tower is several days of storage. Most buyers stop at one or two modules.