Fox ESS battery
Modular battery stacks and hybrid inverters: the good-value pairing for a new solar install.
- Stackable
- sized to the house
- Hybrid inverter
- battery and solar in one
- Value pairing
- the sensible way into both
What it costs to have one fitted
0% VAT until March 2027
Installed price covers the unit, mounting, a dedicated circuit, DNO application, commissioning and the app set up on your phone.
What moves it: how far the unit is from the consumer unit, whether the board has a spare way, whether a gateway is going in for backup, and whether it is going on a wall or standing on the floor.
We give you a figure at the visit and put it in writing. Finance is available; Newpower Advanced Ltd is a credit broker, not a lender (FCA FRN 1037988).
Why the Fox ESS battery
Value with new solar
A Fox ESS hybrid inverter runs both the panels and the battery, and the modules stack underneath it. It is usually the lowest-cost route to solar plus storage that we fit.
Size it to the house
Modules stack, so a two-bed terrace and a five-bed detached each get the size they actually need rather than a fixed 13.5 kWh.
Backup output
The hybrid inverter has an emergency power output for a few essential circuits in a cut, without the cost of a whole-home gateway.
Two ways to fit Fox ESS
With new solar
The natural fit. One hybrid inverter for the panels and the battery, one app, and the stack sized to your usage.
Added to existing solar
An AC-coupled Fox ESS unit sits alongside your existing inverter. If that inverter is old, replacing it with a Fox ESS hybrid at the same time is often the better value.
Full specification.
| Coupling | DC via hybrid inverter, or AC-coupled unit |
|---|---|
| Backup | EPS output for essential circuits |
| Chemistry | Lithium iron phosphate (LFP) |
| Mounting | Floor-standing stack |
| Location | Indoor or sheltered outdoor |
| App | FoxCloud app |
| VAT | 0% until March 2027 |
| Fitted by | Newpower, MCS certified |
Manufacturer specifications. Where we could not source a figure we left the row out rather than guess at it.
Fox ESS battery vs Tesla Powerwall 3 vs Duracell Energy
An honest comparison. We fit all three.
| Fox ESS battery | Tesla Powerwall 3 | Duracell Energy | |
|---|---|---|---|
| Capacity | Stackable | 13.5 kWh | Modular |
| Continuous power | Set by the inverter | 11.5 kW | Varies by model |
| Solar inverter | Fox ESS hybrid | Built in | Separate hybrid inverter |
| Backup | Essential circuits (EPS) | Whole-home, gateway included | Optional, with a gateway |
| Add capacity later | Add modules | Add a second unit | Add modules |
| Warranty | Manufacturer warranty | 10 years | Manufacturer warranty |
Fox ESS is the value choice for a new solar-plus-battery install where the budget matters and whole-home backup does not. Powerwall 3 is the one to beat on power output and whole-home backup; Duracell is the alternative modular stack with a bigger brand behind it.
Tariff pairing: Octopus Flux
With solar, Flux pays the most for what the battery exports in the evening peak. The FoxCloud app sets the charge and discharge windows; we configure them at commissioning and check them again at your review a few months in.
Smart energy tariffs explainedWhy Newpower
- Rated 4.7 on Trustpilot
- MCS NAP-75287 · TrustMark 3658638 · RECC 00078420
- MCS certified installation, and one number to ring afterwards
- A price in writing before you commit to anything
Questions about the Fox ESS battery.
How much does a Fox ESS battery cost installed?
A stack and a hybrid inverter together are usually the best value way into solar and storage at once, and the price turns on how tall the stack needs to be. Zero-rated for VAT until March 2027. You get the figure at the visit, in writing.
Is Fox ESS a good brand?
Fox ESS is one of the most-fitted inverter and battery brands in the UK, and we have fitted a lot of it. It is the value option in our range: not the highest power output, but reliable, expandable and well supported.
Can I add more modules later?
Yes. We leave the space and the cabling for another module if you tell us you might want one.
Does it work in a power cut?
The hybrid inverter has an emergency power output that can run a few essential circuits (lighting, fridge, router) in a cut. It is not whole-home backup; for that, see the Powerwall 3 with its Backup Gateway.
Can I fit it to solar I already have?
Yes, with an AC-coupled Fox ESS unit, or by replacing an old inverter with a Fox ESS hybrid so the panels and battery share one. We recommend at the survey.
How long is the warranty?
Fox ESS warrant the battery and the inverter separately, and we register both for you. Our own workmanship warranty sits on top.
Get a price for a Fox ESS battery.
We come and look, tell you whether this is the right unit for your house, and put the price in writing.