My Honest Battery Comparison
After designing hundreds of systems across South Wales, these are the three I recommend. I don't take commissions from any manufacturer — this is my genuine view.
Updated June 2026 · Based on real installations and customer feedback
GoodWe ESA
Warm Home All-in-One
Best all-rounder for UK homes. Now integrated with Octopus Kraken.
- ✓ Integrates with Octopus Agile/Kraken natively — no third party needed
- ✓ Modular — start small, expand later up to 48kWh
- ✓ All-in-one includes solar, battery, EV charger, heat pump management
- ✓ IP66 rated — can be installed outdoors
- ✓ Solid UK installer network and accessible support
- ✓ Strong price-to-performance ratio
- — 10 year warranty (shorter than EcoFlow)
- — Less brand recognition than Tesla
- — App less polished than Tesla
For most UK homeowners on Octopus Agile, GoodWe ESA is the smart choice. The Kraken integration means it works natively with smart tariffs without needing Home Assistant or Predbat. Modular design means you can start with one battery and expand. Best value for money.
Tesla Powerwall 3
Premium Home Battery
The premium choice. Exceptional after-sales support and the best app on the market.
- ✓ Best customer care in the industry — you can actually reach someone
- ✓ Built-in hybrid inverter — one box does everything
- ✓ Polished Tesla app with clear real-time monitoring
- ✓ Largest single-unit capacity at 13.5kWh
- ✓ 97.5% round-trip efficiency — best in class
- ✓ Strong resale value — Tesla brand recognised by buyers
- ✓ Excellent whole-home backup capability
- — Most expensive option
- — Single fixed capacity — cannot expand modularly
- — Requires DNO approval (G99) — adds 45+ days to timeline
- — Tesla certified installers only — limits choice
If budget allows, Tesla Powerwall 3 is the one I recommend for customers who want the best possible after-sales experience. When something goes wrong — and occasionally things do — you can reach Tesla support and get it resolved. The app is excellent, the efficiency is class-leading, and it adds value to your property.
EcoFlow Ocean 2
Whole-Home Battery Storage
The new challenger. 15-year warranty, 0ms switchover, and V2X ready.
- ✓ 15-year warranty — best in the market by a significant margin
- ✓ True 0ms grid switchover — genuinely seamless whole-home backup
- ✓ Most expandable — up to 60kWh from a single inverter
- ✓ V2X ready — future-proof for vehicle-to-home charging
- ✓ 500+ dynamic tariff integrations including Octopus
- ✓ IP66 with 72hr water immersion — exceptionally weather resistant
- ✓ 10,000+ battery cycles — long operational life
- — Newer product — less long-term real-world track record
- — Pricing not transparent — harder to compare quickly
- — Installer network still developing in the UK
- — Less brand recognition — some customers unfamiliar
The EcoFlow Ocean 2 stands out technically — the 15-year warranty and 0ms switchover are genuinely class-leading. For customers who want maximum future-proofing and the longest warranty protection, this is worth serious consideration. The installer network is growing but not as established as GoodWe or Tesla yet.
Side-by-side comparison
| Feature | 🟢 GoodWe ESA | ⚡ Tesla PW3 | 🌊 EcoFlow Ocean 2 |
|---|---|---|---|
| Battery capacity | 8.32kWh/module | 13.5kWh | 5kWh/module |
| Max expandable | 48 kWh | 13.5 kWh (single) | 60 kWh |
| Inverter size | 3–10kW | 11.04kW built-in | 6–12kW |
| Warranty | 10 years | 10 years | 15 years ✓ |
| IP rating | IP66 | IP56 | IP66 |
| Switchover | <4ms | <20ms | 0ms ✓ |
| Octopus/Agile | Native ✓ | Via app | 500+ tariffs ✓ |
| V2X (car-to-home) | No | No | Yes ✓ |
| App quality | Good | Excellent ✓ | Good |
| Customer care | Good | Best in class ✓ | Developing |
| Price range | £4–7k | £7.5–11k | POA |
| Luke recommends for | Most homeowners | Premium buyers | Future-proofing |
Which one is right for you?
- →You're on Octopus Agile and want native integration
- →You want to start small and expand later
- →You want the best value for money
- →You might add an EV charger or heat pump later
- →After-sales support is your top priority
- →You want the best app and monitoring
- →You have high energy demands (13.5kWh needed)
- →Budget is not the primary concern
- →Maximum warranty (15 years) is essential
- →You want true 0ms whole-home backup
- →You might get an EV and want V2X capability
- →You need a very large system (up to 60kWh)
I have a Fox ESS H1 in my own home and it works well — but only because I've set up Home Assistant and Predbat to compensate for its limitations. The Fox app is poor and their customer care is essentially non-existent in the UK. I wouldn't recommend Fox to customers who want a system that just works with proper support behind it. The three systems above are what I spec for new installations.
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