We’re certified installers of both Tesla and Sigenergy, so we have no incentive to steer you either way. What follows is the framework we use in real consultations, and it starts with a reassurance: there is no wrong answer here. Both are systems we’re happy to put our name to. The question is fit.
Start with how you’ll grow
Powerwall 3 comes in one size: 13.5kWh of usable storage with a powerful integrated inverter. If you need more, you add another Powerwall 3 or a Powerwall 3 Expansion unit. For most three and four bedroom homes, one Powerwall is well sized, and the simplicity is the point.
SigenStor thinks in modules. Battery blocks of about 6kWh or 9kWh stack inside one tower, up to six modules high, and you can add a module later without redesigning anything. If your consumption is about to change, an EV on the way, a heat pump on the horizon, an extension in planning, that flexibility is worth real money, because you can buy for today and expand for tomorrow.
Then think about your tariff
Both systems can charge cheaply overnight and run your home through peak hours. The difference is how hard they work at it. Tesla’s Savings mode is elegant and hands-off. Sigenergy goes further with native support for dynamic tariffs: its AI mode watches the weather forecast and tomorrow’s prices, then positions your energy accordingly. If you’re on an agile-style tariff, or plan to be, SigenStor squeezes out more.
Then your car
If you drive a Tesla, the Powerwall ecosystem is seductive: one app for home and car, and Charge on Solar diverting your surplus straight into the battery on your driveway. If you want the fastest possible home charging, SigenStor’s optional EV DC module delivers up to 25kW directly from solar and battery, several times quicker than a standard 7kW wallbox.
Backup, apps and track record
Both offer backup through their respective gateways, covering the whole home or chosen circuits depending on the design: Tesla’s Backup Gateway 2 switches over automatically and quickly, while Sigenergy rates its Gateway at no break at all when the backup load is within the system’s rating. The Tesla app is polished and simple; mySigen shows more and lets you control more, at the cost of a busier screen. Tesla has been selling home batteries since 2015; Sigenergy is newer, but growing quickly.
Our honest rule of thumb
- Choose Powerwall 3 if you value proven simplicity, drive a Tesla, or want the most hands-off ownership.
- Choose SigenStor if you want modular capacity, run (or plan to run) a dynamic tariff, want DC-fast EV charging at home, or love granular control.
Still torn? Send us a recent energy bill and we’ll model both systems against your actual usage. The right answer usually becomes obvious. See the full side-by-side on our comparison page.
This guide is general information, not advice for your specific property. Every Powergy proposal is modelled on your actual roof, usage and tariff. Figures reflect typical UK conditions at the time of writing.