What battery storage systems do you install?

We install leading brands including Tesla Powerwall and GivEnergy. We advise on the right capacity for your home based on consumption and generation profile.

Can I add battery storage to my existing solar panels?

Yes. We retrofit battery systems to most existing solar installations. We assess your inverter compatibility and DNO requirements before recommending a solution.

How much can I save with a home battery?

Savings depend on your tariff, generation and consumption. Most customers significantly reduce grid imports by storing daytime solar generation for evening use.

Smart Battery and EV Charger Installation Surrey and SW London | Octopus Intelligent | Dynamic Load Balancing

Two Storage Systems, One Overnight Window, One Exceptionally Low Cost Per Kilometre

A Porsche Taycan costs approximately 3.50 GBP to fully charge at standard daytime grid rates of 28 to 35p/kWh. On Octopus Intelligent overnight off-peak rates of 7 to 9p/kWh, the same full charge costs under 85p. A home battery and an EV charger installed together under Octopus Intelligent creates a compound financial engine that exploits this price differential across two separate storage vessels simultaneously. From 23:30 to 05:30 every night, the system automatically draws ultra-low-cost electricity from the grid to fill both the vehicle battery and the home battery in a single coordinated off-peak session. By 5:30am, the Taycan is fully charged for under 85p and the home battery holds 13.5kWh of cheap electricity at the same rate. The house then runs entirely on that stored cheap power throughout the day, never touching standard daytime grid rates until the next overnight charging window begins. For a Surrey or SW London household with a premium EV covering 15,000 miles per year, this two-vessel overnight strategy reduces the combined annual energy and fuel cost by 2,800 to 4,500 GBP compared with standard tariff charging.

Three Engineering Pillars of the Integrated Battery and EV Charger System

Home energy app showing solar import and export — battery discharge savings London MCS electricalworks

Octopus Intelligent Synergy - Two Vessels, One 7p/kWh Window

Octopus Intelligent is the first UK tariff to manage EV charging and home battery charging as a coordinated overnight programme. The Octopus API communicates with both the home battery management system and the EV charger simultaneously, scheduling the full overnight charge cycle to complete within the 23:30 to 05:30 off-peak window at 7 to 9p/kWh. The home battery fills its full capacity. The EV battery charges to the target state of charge. Both draw from the same ultra-low-cost overnight session. For a Surrey household with a Porsche Taycan and a 13.5kWh home battery covering 15,000 EV miles per year, this coordinated overnight strategy saves approximately 1,800 to 2,400 GBP per year in combined energy and fuel costs versus standard daytime grid charging for both.

Wall-mounted lithium home battery with isolators — backup power for London homes G98 compliant MCS

Dynamic Load Balancing - Protection for the Full Estate Electrical Environment

A luxury Surrey or SW London property with a 100A single-phase supply has a maximum safe simultaneous load of approximately 23kW. A 7.4kW EV charger running concurrently with a 5kW battery charging at peak rate, a 7kW induction hob, and a 3kW heat pump compressor cycle brings total simultaneous demand to 22.4kW - within 600W of the supply limit. Without active dynamic load management, an unplanned load spike crosses the supply fuse rating. Our integrated systems install a current transformer on the main incoming tails that feeds real-time total demand data to the battery inverter and the EV charger simultaneously. Both devices modulate their output in response to ensure total demand never breaches the supply limit at any instant - completely in the background, with no user intervention required.

Retrofit AC-coupled battery beside existing solar — increased self-consumption London electricalworks

V2H-Ready Infrastructure and 0% VAT on the Battery Component

A Porsche Taycan carries 93kWh of energy. An Audi Q8 e-tron carries 114kWh. These are not just transport assets - they are mobile energy storage units that will soon be capable of powering a luxury estate for three to five days through Vehicle-to-Home technology. We design every battery and EV charger installation with the earthing topology, consumer unit architecture, and cable sizing that Vehicle-to-Grid and V2H systems will require when bidirectional chargers become mainstream. The infrastructure installed today will not need structural rework to support this capability. Additionally, the home battery component of every combined installation qualifies for 0% VAT under current UK legislation - reducing the total project cost by 1,400 to 2,400 GBP at invoice.

Battery Partners

Installation Gallery

Tesla Powerwall 2

Richmond, TW10

Myenergi Libbi modular battery system — expandable storage with solar diversion London MCS

MyEnergi AIO

Clapham, SW4

Solis hybrid inverter with battery port — DC-coupled storage option for London PV upgrades

Solis Home

Hampstead, NW3

Loft-mounted battery inverter system — space-saving install with fire detection London BS 7671

Loft Install

Ealing, W5

From Load Assessment to Live Octopus Intelligent Synergy

Load Profile and Supply Assessment

We retrieve your half-hourly Smart Meter consumption data, map your full estate load profile, and confirm your incoming supply rating and available simultaneous capacity. This assessment establishes whether dynamic load balancing is required and determines the maximum EV charger output and battery charge rate that can operate concurrently within safe margins.

Integrated System Co-Design

Battery capacity, EV charger specification, CT sensor placement, and dynamic load balancing configuration are co-designed as a single programme. We select the battery platform and EV charger combination with confirmed Octopus Intelligent API compatibility and V2H-ready earthing topology from the outset.

Single-Programme Installation

Our NAPIT master electricians install the battery, EV charger, and CT sensor load balancing hardware as one co-ordinated programme. All cabling is concealed through building fabric. The EV charger is positioned for architectural integration with concealed cable routing to the parking location. Battery installation follows PAS 63100 fire safety standards throughout.

Octopus Intelligent Commissioning

We configure the Octopus Intelligent API link for both the home battery and the EV charger, verify dynamic load balancing is operating correctly across the full simultaneous load range, and issue all warranty documentation and 0% VAT invoice before engineers leave. Both systems begin operating in coordinated overnight mode from commissioning day.

The Engineering Detail of an Integrated Battery and EV Charger System

Octopus Intelligent Off-Peak Synergy - The Financial Mechanics

Between 23:30 and 05:30, the Octopus Intelligent API co-ordinates both the home battery and the EV charger to draw simultaneously from the grid at 7 to 9p/kWh - filling two storage vessels in one cheap overnight window.

The home battery management system and the EV charger both connect to the Octopus API. The API receives half-hourly grid pricing data 24 hours ahead and schedules the optimal charge session for both devices within the guaranteed off-peak window. By 05:30, the Taycan or Model 3 is charged to target state and the home battery holds a full 13.5kWh of electricity purchased at under 9p/kWh - which then powers the estate throughout the day at full grid replacement value of 25 to 35p/kWh.

EV full charge cost: under 85p for a Porsche Taycan on Octopus Intelligent versus 3.50 GBP at standard daytime rate
Home battery fill cost: 13.5kWh at 8p = 1.08 GBP overnight versus 4.05 GBP at 30p/kWh daytime
Combined annual saving: 1,800 to 2,400 GBP versus standard daytime charging for both vessels
Zero management required: Octopus API schedules every charge session automatically

AC-coupled battery inverter schematic - retrofit battery on existing solar London MCS

DC-coupled battery with hybrid inverter - higher round-trip efficiency new solar London electricalworks

Dynamic Load Balancing - Protecting the Estate Supply Fuse

Simultaneously charging a 7.4kW EV and a 5kW home battery on a property already running heat pumps and climate control can exceed the incoming supply rating - dynamic load balancing prevents this automatically.

A current transformer installed on the main incoming tails measures total property current draw in real-time and feeds this data to both the battery inverter and the EV charger simultaneously. Both devices respond by modulating their charge rates to ensure total simultaneous demand never breaches the supply limit. When high-draw appliances cycle off, the chargers automatically increase back to maximum output.

CT sensor monitoring: total estate demand measured in real-time at the main incoming tails
Dual-device response: battery inverter and EV charger both receive and act on the CT data simultaneously
No manual management: operates completely in the background with zero user intervention
Maximum available charging: both devices run at full output whenever the infrastructure safely allows it

Modular battery stack expansion - scalable kWh for growing EV and heat pump loads London

V2H-Ready Infrastructure - Preparing the Estate for Bidirectional EV Power

A Porsche Taycan holds 93kWh. An Audi Q8 e-tron holds 114kWh. These are not just transport assets - they are mobile energy reserves that will soon be capable of powering a luxury estate for three to five days.

Vehicle-to-Home technology requires specific consumer unit earthing topology, dedicated bidirectional charger circuits, and cable sizing capable of handling bidirectional high-current AC flow. We design and install every combined battery and EV charger system with this future capability pre-engineered into the infrastructure. When V2H chargers become widely available for premium EV platforms, your estate's electrical architecture will support them without structural rework.

V2H earthing topology: consumer unit earthing designed for bidirectional operation from day one
Bidirectional cable sizing: charger circuit cabling rated for both import and future export current requirements
No rework required: infrastructure supports V2H charger hardware installation when available for your vehicle platform
93 to 114kWh potential reserve: premium EV battery capacity sufficient for 3 to 5 days of full estate autonomy

Battery installed in ventilated utility room - clearance and fire regulation compliance London

Heat and smoke detection near battery store - insurance and DNO best practice London install

0% VAT on Battery Storage and Server-Grade Aesthetics Throughout

The home battery component of every combined installation qualifies for 0% VAT - a direct capital saving of 1,400 to 2,400 GBP at invoice, with no application or registration required.

The aesthetic standard of the installation must match the standard of the property. EV charger cable routes are surveyed through building fabric before any work begins - roof voids, internal wall cavities, and underfloor channels where possible. The charger unit itself is specified for architectural compatibility: zappi for solar-diversion capability, Andersen A2 for heritage and period properties, or Tesla Wall Connector for Tesla owners requiring full vehicle integration.

0% VAT on battery: hardware, inverter, mounting, cabling, and labour all zero-rated at invoice
Capital saving: 1,400 to 2,400 GBP on a typical Surrey battery installation
Concealed cable routing: EV charger cabling surveyed through building structure before installation
Premium charger selection: zappi, Andersen A2, or Tesla Wall Connector specified for your vehicle and property

Agile import export grid trading screen - battery arbitrage with Octopus-class tariffs London

SMETS2 smart meter with CT clamps - accurate import export for battery control London MCS

Client Success Stories

James O.

Wimbledon, SW19

★★★★★

"Tesla Powerwall 3 and a zappi EV charger installed together as one programme. The dynamic load balancing was explained clearly before installation - we have a heat pump and an induction hob and the team confirmed our supply rating needed it. The Octopus Intelligent configuration was set up on commissioning day. Charging the Model Y overnight now costs under 1 GBP. The combined saving versus what we were paying before is running at nearly 200 GBP per month."

Elena M.

Weybridge, Surrey

★★★★★

"We have a Porsche Taycan and wanted a system that would charge it as cheaply as possible without solar. The GivEnergy AIO battery and the Andersen A2 charger were installed in a single day - no visible cabling anywhere. The Octopus Intelligent setup means both the car and the home battery fill overnight automatically. The Andersen unit suits the property perfectly - we were told by a neighbour they hadn't noticed we had a charger at all."

What Every Premium EV Owner Should Know Before Installing a Home Battery

Battery cycle life versus depth of discharge chart — warranty expectations London MCS customers

How Octopus Intelligent Differs from Octopus Go

Octopus Go provides a fixed off-peak window from 00:30 to 04:30 at a set rate. Octopus Intelligent provides a 6-hour window from 23:30 to 05:30 with flexible scheduling - the API actively manages your EV charger and home battery to optimise both charge sessions within that window, responding to dynamic pricing within the period. For a household charging both a premium EV and a home battery simultaneously, the 6-hour Intelligent window provides more scheduling flexibility and typically delivers 15 to 20 percent lower overnight charging costs than a fixed 4-hour Go window.

Hybrid inverter commissioning menu — battery charge limits and grid charge settings London

Why Dynamic Load Balancing Is Non-Negotiable for Luxury Homes

A standard UK residential single-phase 100A supply has a practical simultaneous capacity limit of approximately 23kW. A 7.4kW EV charger operating with a 5kW battery, a 9kW heat pump, and a 3kW underfloor heating zone already totals 24.4kW - over the safe limit. Without active CT-sensor dynamic load balancing, this combination blows the supply fuse. With it, the chargers automatically step back to accommodate the other loads and return to full output when they cycle off. This is not an optional safety feature for a large Surrey estate - it is a fundamental requirement of a correctly engineered installation.

Winter solar yield versus battery reserve — seasonal performance expectation London electricalworks

The Financial Case Without Solar

A home battery and EV charger installation without solar panels is a compelling standalone investment for premium EV owners. The combined annual saving from Octopus Intelligent overnight charging of both the vehicle and the home battery - versus standard daytime grid rates for equivalent consumption - is 1,800 to 2,400 GBP per year for a Surrey household with a Porsche Taycan or Audi e-tron covering 15,000 miles annually. At 0% VAT on the battery component, the combined project payback period on savings alone is typically 4 to 6 years - before any future EV running cost increases are considered.

Frequently Asked Questions

Does the home battery qualify for 0% VAT when installed with an EV charger?

Yes. Under current UK HMRC energy-saving materials legislation, standalone home battery storage qualifies for 0% VAT regardless of whether it is installed with or without solar panels, and regardless of whether an EV charger is included in the same project. The zero rate applies to the battery module, inverter, mounting hardware, cabling, and installation labour. The EV charger element of the project is invoiced separately at the standard 20% VAT rate - we itemise both elements clearly at quotation stage so the 0% battery saving is immediately visible in the total investment figure.

Can the home battery and EV charger really charge simultaneously without overloading the fuse?

Yes, when the system is correctly engineered with active dynamic load balancing. Without DLB, simultaneous operation of a 7.4kW EV charger, a 5kW battery, and typical luxury estate loads can easily exceed a standard single-phase 100A supply limit. A CT sensor on the incoming supply tails measures total property demand in real-time and feeds this data to both the battery inverter and the EV charger, which modulate their charge rates to ensure the combined load stays within the supply rating at all times. We assess your specific supply rating and estate load profile during the pre-installation survey and design the DLB configuration accordingly.

What is the annual financial saving from installing a battery and EV charger together on Octopus Intelligent?

For a Surrey or SW London household with a premium EV covering 15,000 miles per year (approximately 4,300 kWh of charging) and a 13.5kWh home battery cycling daily, the combined annual saving on Octopus Intelligent versus standard daytime tariff charging is approximately 1,800 to 2,400 GBP. This comprises approximately 900 to 1,200 GBP in reduced home energy costs from overnight battery charging, and approximately 900 to 1,200 GBP in reduced EV fuel costs. We model your specific vehicle, mileage, and household consumption profile and provide this forecast at quotation stage.

What is Vehicle-to-Home and should I think about it now?

Vehicle-to-Home technology allows your EV battery to discharge stored electricity back into your property, effectively turning the car into a large home battery. A Porsche Taycan with 93kWh of usable storage could power a large Surrey estate for 3 to 5 days. V2H requires specific bidirectional charger hardware and consumer unit infrastructure. While V2H chargers for premium European vehicles are not yet widely available in the UK, we design every combined battery and EV charger installation with the earthing topology and cable sizing that these systems will require - so your estate can support V2H hardware when it becomes available for your vehicle platform without any structural rework.

Commission Your Battery and EV Charger System in Surrey or SW London

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Battery + EV Charger: The Ultimate Off-Peak Synergy for a Porsche Taycan or Tesla Running on 7p/kWh