Best value
Most fitted
Fox ESS EP6 & EP12
5.76 kWh or 11.52 kWh
- The lowest price for the storage you get
- Add a second unit later in the same footprint
- 10-year Fox ESS warranty
Battery Storage · MCS-accredited
Store cheap power. Use it when prices spike.
Add a home battery — with or without solar — and stop paying peak rates. Charge when electricity is cheapest (or free from your panels), then run your home through the expensive evening hours. We handle the design, install and paperwork. Fitted from£1,990 See every battery price →
- MCS accredited
- 0% VAT on solar & battery
- 24-hour quote
- Owner-led installs
What we fit
Three brands. We tell you which suits your home.
These three cover every home we survey. We recommend the one that fits how you use power — and say so when the smallest is the right answer.
EV & heat-pump ready
Sigenergy SigenStor
Modular — sized to your home
- For homes adding an EV or heat pump next
- One app for battery, charger and heat pump
- 10-year Sigenergy warranty
Biggest single unit
Tesla Powerwall 3
13.5 kWh per unit
- Highest output of the three — whole-house capable
- Takes solar straight in through its own inverter
- 10-year Tesla warranty
Why add a battery
Stop selling your power back cheap.
Beat the evening peak
Charge when electricity is cheapest — overnight or straight from your panels — then run your home on it when grid prices are highest.
Use more of your own solar
Without a battery, spare daytime solar is sold back cheaply. Store it instead and use it after dark.
Optional backup
Set up with backup for your essential circuits, so the lights stay on if the grid goes down.
Sized to your home
We size the battery to your actual usage — no overselling, no undersized regret.
Already have solar?
We add batteries to systems other installers fitted.
It does not matter who fitted your panels. We add a battery to your existing system, and we replace failed inverters. If your inverter is a compatible hybrid, a battery is added from £1,990 fitted; if it is not, we fit a battery with its own new inverter from £3,290.
Choosing a size
How much storage do I need?
Battery size is in kWh. One kWh is one unit on your electricity bill. We size yours from your real usage at the survey, so you never pay for storage you will not fill.
5.76 kWh
A smaller home, 1–2 bedroomsCovers an evening’s use. Fox ESS EP6.
11.52 kWh
A family homeA full evening and night. Fox ESS EP12 — the one most homes choose.
13.5 kWh+
Bigger homes, an EV or a heat pumpPowerwall 3, Sigenergy, or two Fox units stacked.
One of ours
Neat, labelled and done in one visit
Left to right: two Fox ESS batteries, the hybrid inverter that runs them, the isolator and an EV charger. Cables clipped and run properly, not draped down the brick. We test it, switch it on and set up the app with you before we leave.
Checked and certified. Every install is registered and signed off under the schemes below.
MCS-certified installer · Cert. no. NAP/79987/26/1
Why ECONEXIS
Why have ECONEXIS fit it.
No subcontractors
The people who design your system are the people who fit it. A company owner is on site for your whole installation — start to finish, not a subcontracted crew you have never met.
We handle everything
MCS certificate, electrical certificate and all the paperwork — managed by us, so you don't lift a finger.
Insurance-backed guarantee
Premium tier-1 panels with a 25-year warranty, protected by an insurance-backed guarantee with the IWA (Independent Warranty Association).
How it works
From first click to fitted — in three steps.
1
Tell us about your home
A 60-second form — or call us if you'd rather talk.
2
Your free roof design and fixed price
We design around your roof, confirm it on site and put the price in writing — no obligation.
3
Approve & install
An owner on site, fully certified, fitted in as little as two weeks.
Battery storage questions
Do I need solar panels to add a battery?
No. A battery works on its own — you charge it from the grid when rates are lowest (usually overnight) and use that cheaper energy during peak hours. It works even better paired with solar.
What size battery do I need?
It depends on your usage and whether you have solar. We size it at survey so you're not paying for capacity you won't use.
Will it power my home in a blackout?
Many systems can be set up with backup for essential circuits. We'll talk through the options for your home at the survey.
How long does a battery last?
Quality home batteries are warrantied for around 10 years and typically keep performing well beyond that.
Which batteries do you fit?
Fox ESS (the EP6 and EP12), Sigenergy SigenStor and Tesla Powerwall 3 — chosen to suit your home and budget.
How much does a home battery cost?
From £1,990 fitted when added to a hybrid inverter you already have, or from £3,290 as a new battery and inverter together. Every price is on our battery cost page.
How long does fitting take?
One day, in one visit. Adding a battery to an inverter you already have is usually half a day.
Can I add more storage later?
Yes. Fox ESS batteries stack in the same footprint, so a second unit is an addition, not a whole new system.
What paperwork do I get?
Your MCS certificate, the electrical certificate and the network operator paperwork. We file all of it for you.
Is a battery right for your home?
A short call is usually enough to tell you — and we will say so plainly if it is not worth it for you.