How to Run a Battery Storage Installation Project

What you will learn

• Why site survey and PAS 63100:2024 compliance must be confirmed before any quote is issued.
• How to size a battery system correctly and choose between DC coupling and AC coupling architectures.
• The procurement and pre-installation steps that prevent installation day delays.
• What DNO notification requirements apply and when to submit them relative to the installation date.
• How to commission, test, and issue documentation that satisfies MCS standards.
• The four most common failure points on battery storage projects and how to avoid them.

Battery storage is now a mainstream service line for UK renewables installers. Demand from residential customers wanting to pair storage with existing solar PV, or add standalone storage to shift off-peak grid electricity, is driving consistent pipeline growth. Running these projects well requires more than electrical competence - it requires a documented process from initial enquiry through site survey, procurement, installation, commissioning, and MCS registration, with clean handover at every stage.

This guide covers the full operational lifecycle of a domestic battery energy storage system (BESS) project, written for MCS-certified installers and renewables businesses looking to standardize how they handle these jobs.

Key Takeaways

• Why site survey and PAS 63100:2024 compliance must be completed before any quote is finalized
• How to size and specify a battery system correctly, including DC-coupling versus AC-coupling decisions
• The procurement and pre-installation steps that prevent installation day delays
• What DNO notification requirements apply and when to submit them
• How to commission, test, and issue documentation that meets MCS standards
• Common failure points that cause MCS registration delays and how to avoid them

Step 1: Initial Enquiry and Job Qualification

Every battery storage project starts with a qualification call. Before you commit engineer time to a site visit, establish the basics: Does the customer already have solar PV? If so, how old is the system and who installed it? What is their approximate annual electricity consumption? Are they targeting backup power, bill reduction, or SEG income? What is the installation address and site access situation?

This information shapes the survey agenda and the system design before your engineer sets foot on site. A customer with a 4kWp DC-coupled solar system installed in 2020 presents a very different technical brief to a customer who wants a standalone battery on a smart tariff with no panels at all.

Collect this on a standardised enquiry form and log it against the lead in your job management system before the survey is booked. If the customer already has solar panels that were installed by another business, request the original MCS certificate and electrical installation documentation at this stage - not on installation day.

Step 2: Site Survey

The site survey is the technical foundation of the entire project. It has two purposes: gathering the data to design the right system, and confirming that the installation can proceed safely in compliance with PAS 63100:2024 fire safety standards.

Energy and system assessment

Review the customer's electricity bills and any monitoring data from existing solar panels. Calculate average daily consumption and identify the peak load pattern. For a solar retrofit, check the existing inverter compatibility with your preferred battery brands and confirm whether DC coupling or AC coupling is the correct architecture for this system.

Location assessment under PAS 63100:2024

Under the PAS 63100:2024 fire safety standard, battery storage systems must not be installed in lofts, bedrooms, stairwells, or small cupboards. The standard came into effect for new UK domestic installations in 2024 and specifies that batteries must be mounted on fire-resistant surfaces in well-ventilated spaces. Suitable locations include garages, utility rooms, and purpose-built external enclosures.

Your surveyor must confirm the proposed location and document why it meets the standard. BS 7671 Amendment 4, which introduced a dedicated Chapter 57 covering stationary secondary battery installations, became mandatory from April 2026. Your installation documentation must reflect compliance with Chapter 57 requirements including ventilation, fire protection, disconnection arrangements, and overcurrent protection.

Electrical assessment

Check the customer's consumer unit capacity. Confirm there is sufficient space for the additional circuit breakers the battery installation requires. Note the distance from the consumer unit to the proposed battery location - this affects cable runs and cost. Photograph the consumer unit, meter, and proposed installation location for use in the system design.

Survey outputs

Before leaving the site, the surveyor should have documented: proposed battery location and confirmation of PAS 63100:2024 compliance, existing system details (if solar retrofit), consumer unit capacity and cable routing plan, and any access or structural considerations that affect installation day logistics.

Step 3: System Design and Quotation

With survey data in hand, design the system before producing the quote. The majority of domestic UK battery installations fall in the 5kWh to 15kWh capacity range. System sizing depends on daily consumption, solar generation profile (if applicable), and the customer's energy goals.

Decide on coupling architecture:

• DC coupling integrates the battery directly with the solar array via a hybrid inverter. It is more efficient and is the standard approach for new combined solar-and-battery installations. If the customer has a DC-coupled solar system with a compatible hybrid inverter, DC coupling is usually preferable.
• AC coupling connects the battery to the AC side of the consumer unit. It is simpler to retrofit onto existing solar installations where the existing inverter is not battery-compatible, though there is a small efficiency penalty compared to DC coupling.

Build the quote from the confirmed system specification: battery unit, inverter (if hybrid), mounting hardware, cable, circuit protection, and labour. Include all compliance documentation costs - Electrical Installation Certificate (EIC), DNO notification, and MCS registration - as line items so they are visible to the customer and not buried in overhead.

The average cost of a domestic battery storage installation in the UK is approximately £8,900, according to MCS data for 2025. This figure includes supply and installation and varies with system size, brand, and site complexity.

Step 4: DNO Notification and Pre-Installation Preparation

Once the customer has accepted the quote, two processes must run in parallel: equipment procurement and DNO notification.

DNO notification

Most domestic battery storage installations are notifiable to the local Distribution Network Operator under G98 (systems up to 3.68kW export capacity per phase) or G99 (larger systems). Submit the DNO notification as soon as the job is accepted - not the week before installation. G98 notifications are straightforward, but G99 applications can take 45 working days or more for DNO review, and your installation date must not be booked before approval is confirmed.

Your job management system should log the notification date, DNO reference number, and expected approval date against the job record so nothing is missed when the installation is scheduled.

Procurement

Order the battery unit, inverter (if required), and ancillary materials immediately after quote acceptance. Lead times on popular brands can run to several weeks during periods of high demand. Confirm delivery addresses - some battery units are delivered directly to site, others to your depot for pre-staging. Ensure delivery is confirmed at least two days before the installation date so you are not chasing freight on the morning of the job.

Pre-installation checklist

1. Confirm DNO notification is submitted and reference number is logged against the job
2. Confirm equipment ordered and delivery date is confirmed against the installation date
3. Source correct battery mounting hardware and fire-rated fixings for the confirmed location
4. Brief the installation engineer on site survey notes, cable route, and consumer unit configuration
5. Contact the customer to confirm site access and any on-site requirements

Step 5: Installation Day

Most domestic battery storage installations take one to two days depending on system complexity and the extent of electrical work required at the consumer unit.

The installation sequence typically runs:

1. Arrive on site and complete a toolbox talk - confirm safe working area, electrical isolation procedure, and emergency access
2. Mount the battery unit in the confirmed location using fire-rated fixings on a certified fire-resistant surface
3. Run cable from battery to consumer unit following the agreed route, concealing cables where required per scope
4. Install circuit breakers, MCBs, and RCDs in the consumer unit to protect the new battery circuit
5. Connect battery to inverter and solar array (DC coupling) or consumer unit (AC coupling) per manufacturer wiring diagram
6. Install labelling on battery, consumer unit, and cable runs per BS 7671 Chapter 57 requirements
7. Carry out isolation test and initial electrical checks before energizing

Throughout the installation, photograph each stage: mounting, cabling, consumer unit modifications, and labelling. These photographs form part of your MCS compliance documentation and are essential if the installation is ever audited.

Step 6: Commissioning and Testing

Commissioning a battery storage system involves more than confirming it powers on. Your engineer must verify that the system is functioning correctly across its full range of operating modes.

Run through the manufacturer's commissioning procedure and record the results. Confirm:

1. Battery charges from solar generation (if solar retrofit) - verify by monitoring inverter output
2. Battery charges from the grid on-demand or via a smart tariff schedule as applicable
3. Battery discharges correctly to household loads
4. All protection devices function correctly - test isolation switch and confirm MCBs trip correctly
5. Monitoring app is configured and connected to the customer's Wi-Fi, and readings are visible before leaving site
6. Customer is walked through the monitoring app and understands how to read state of charge, daily generation, and consumption data

Issue the Electrical Installation Certificate before leaving site. Complete the commissioning checklist and retain a copy for your MCS quality management system documentation.

Step 7: MCS Registration and Handover

Every MCS-accredited battery storage installation must be registered on the MCS Installation Database within the required timescale after completion. Your customer will receive their MCS certificate within 10 working days of the registration being completed.

The MCS certificate matters to the customer for several reasons: it is required for Smart Export Guarantee (SEG) registration, it is needed if the customer remortgages or sells the property, and it confirms that the installation meets the quality standard for warranty purposes.

The handover pack you provide to the customer should contain:

• Electrical Installation Certificate
• DNO notification confirmation and approval paperwork
• MCS certificate (or confirmation it is in progress)
• Battery manufacturer warranty documentation and contact details
• Monitoring app login credentials and user guide
• Maintenance schedule and contact details for your aftercare service

Before closing the job in your system, confirm the MCS registration is submitted and log the certificate number against the job record. Set a reminder to follow up with the customer 30 days after installation to check the monitoring data looks correct - this is the single best way to catch any configuration issues before they become warranty claims.

Common Failure Points

Battery storage projects most often go wrong in one of four areas.

Location compliance missed at survey stage. Installing a battery in a loft or internal cupboard without verifying PAS 63100:2024 compliance creates a rework problem. This is always a survey discipline failure, not an installation day failure.

DNO notification submitted too late. Booking an installation date before DNO approval is confirmed on G99 applications regularly causes project delays. Submit the notification the same day the job is accepted, and do not book the installation date until approval is in hand.

Procurement not locked in promptly. Some battery brands have four to six week lead times in peak periods. If equipment is not ordered at quote acceptance, the installation date slips and the customer experience suffers.

MCS registration not completed promptly. Batching up MCS registrations at the end of the month is common in smaller businesses but creates unnecessary customer queries about their certificate and SEG eligibility. Register each installation promptly after completion.

A battery storage installation is a manageable one or two-day job when the process is properly set up. The operational disciplines that determine whether these projects run well are nearly all front-loaded: thorough site surveys, early DNO notification, prompt procurement, and pre-installation engineer briefings. With a documented process and a clear handover checklist, most battery storage projects move from initial enquiry to MCS certificate in three to five weeks, with minimal rework and a customer ready to refer you to their neighbours.

• MCS Certified Domestic Battery Installation StatisticsGOV.UK / Department for Energy Security and Net Zero · accessed 2026-06-15
• Battery Storage Installation Training UK: City & Guilds 2923 Guide (2026)Learn Trade Skills · accessed 2026-06-15
• Battery Storage - MCSMCS Certified · accessed 2026-06-15
• How is Solar Battery Storage Installed? 2026 GuideSwitch Together · accessed 2026-06-15

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