System upgrade · Information guide

Add battery storage to existing solar panels

You have a solar-only system and want to add battery storage to use more of your generation and reduce grid dependence. Before you commit to a battery retrofit, you need to understand coupling options, inverter compatibility, costs, and DNO requirements.

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AC coupling works with most systems
Not all inverters support DC coupling
DNO notification required

Unsure if your system is compatible?

A solar system health check includes an assessment of your current inverter, generation profile, and the best battery retrofit option for your setup — whether AC coupling, DC coupling, or a different approach entirely.

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13 Trustpilot reviews

Trustpilot Google

I have a GivEnergy system consisting of two batteries, two inverters and a controlling EMS (Energy Management System) which has not worked since Nov 2025. After six months I discovered Solar Tech Support, reached out to them and Ron phoned me back – how often do you get that service? Could not be more helpful – worked directly with me over the phone, outside what I would call normal working hours. Lucid explanations and we were able to discuss the issues and history using camera and email history. As this was a very rare setup, Ron was able to access an EMS expert in the field to confirm the solution. One sunny day in, I am now only paying for standing charge and a few pence for spikes in grid consumption while battery catches up with house demand.

Ian · May 2026 Trustpilot

When my GivEnergy system had an issue, I was completely left without support and had honestly lost all hope. Thankfully, I searched online and found Ron, which completely turned things around. After sending him a message, he responded incredibly fast and called me to assure me that he would get the problem fixed. I really admire his dedicated, supportive nature and his determination to find a solution. With this kind of outstanding attitude and customer service, he has absolutely secured a future customer in me.

Sree · May 2026 Trustpilot

Ron want out of is way to help, nothing was to much. He was very thorough in what he did Very knowledgeable I would highly recommend Ron and his company He did a fantastic job for me. if you have any problems, he'll do his best to help you out and resolve your problem. I wouldn't hesitate to recommend them

Dennis Brown · May 2026 Trustpilot

Ron took me through a diagnostic to confirm my GivEnergy Inverter had a fault. A common one as it turns out with the AC Inverter. As GivEnergy is defunct there is no immediate fix, aside from sourcing 2nd hand replacement. It may be that a fix becomes available over the summer which would make a lot of GivEnergy customers happy (Again)

Tony Deacon · May 2026 Trustpilot

Contacted Ron with a problem and he sorted it out quickly with no problems at all. Very knowledgeable on anything solar/ batteries. I would recommend him to anyone

Phill · May 2026 Trustpilot

I've spoken to Ron a couple of times with issues with my Givenergy installation. Such a friendly knowledge guy very highly recommended. Thank you very much for resolving my issues

michael fairhurst · May 2026 Trustpilot

Contacted Solar Tech Support in desperation. After explaining the issues I had with my system a diagnosis was made and a solution proposed. Fantastic service, even contacted a manufacturer to arrange replacement parts for me. Great communications, explained all they were doing and what I had to do, clearly and precisly. Followed up to confirm all was ok. Excellent service.

Mr Machin · May 2026 Trustpilot

After GivEnergy went into liquidation, just my luck, my battery started playing up (internal board crashed). Contacted my installer - not interested! Found Solar tech support on a Google search. Sooo glad I found this company! Ron is extremely helpful and has plenty of experience. He soon confirmed what the fault was, and helped me to get my system up and running again. Now moved my GivEnergy account to Solar tech support, and will definitely use again if I have more issues. Unusual to find such a helpful company in these times, no morons reading scripts, just direct contact with the engineer.

Keith Ballard · Apr 2026 Trustpilot

Contacted Solar Tech Support when trying to understand what my Givenergy inverter problem might be and what might be my options. Received good/honest advise which backed up my thoughts.

Hugh Speirs · Apr 2026 Trustpilot

Ron is a super star. Two months ago my GivEnergy battery failed a firmware upgrade leaving it a brick. My installer couldn't/wouldn't fix it. GivEnergy couldn't/wouldn't fix it. Then they went into administration and all hope was lost. A flurry of emails later and Ron had diagnosed the fault (failed USB flash drive, something I'd suspected) and talked me through resolving it. Two months of nothing resolved in about 3 hours. It's great to work with someone who pays attention to the details, knows that they're doing (not just following a script) and gets stuff sorted without a fuss or up-charging.

Christopher · Apr 2026 Trustpilot

I can add to the list of customers who had already 'given up' on GivEnergy due to their appalling customer service, and that was before they went into administration (their Trustpilot reviews don't lie!). So you can imagine my desperation when, having changed my ISP and my Inverter, predictably, proving to be the only device that didn't connect automatically to my new network, I found zero prospect of any customer support with GivEnergy having called in the administrators just five days earlier! The salvation came from Solar Tech Support. My IT advisor stumbled across their web site and some very helpful tips for beleaguered GivEnergy customers, as well as an offer to provide direct assistance. Nothing ventured, I decided to drop them an E-Mail, with very low expectations based on my experience of GivEnergy customer support. Within an hour Ron had responded with some pin point advice, and after a few exchanges of E-Mails he had nailed the problem, enabling the combined efforts of my IT advisor and solar installer to resolve it and reconnect my Inverter. Thank you Solar Tech Support, and Ron in particular, for coming to the aid of a deserted and despondent GivEnergy customer. Expert, razor sharp advice and first class customer service, even though I wasn't officially a customer.

customer · Apr 2026 Trustpilot

This company are a rare gem, I had a very unusual problem following a failed firmware upgrade on my GivEnergy kit. I then found out GivEnergy were in administration and had dismissed all their support staff! None of the usual fixes to try and restore my inverter comms would work, and I looked everywhere, forums, GivEnergy youtube support videos - even AI couldn't figure it out. My installer was talking about huge sums for system replacements, and being vague / evasive about if they'd even install replacement GivEnergy inverter. Enter Solar Tech Support, reassuring and knowledgeable from the very start, I've learnt loads about my solar system though the friendly chat while my engineer worked as he diagnosed the problem and figured out a fix procedure that I've not found anywhere else - amazing . If you need solar system repairs - especially if you like me have been left high and dry by GivEnergy, I cannot recommend this company enough. Give them a call.

Andy Thomas · Apr 2026 Trustpilot

I sent a message on their website regarding a problem I have on my Givenergy system. Although not supplied by Ronald, I thought it was worth an email. Within the hour on a Saturday, he phoned and we discussed the problem. He logged in remotely and gave excellent advice. I'm too far away for his on-site help but he did diagnose the problem and was happy also to chat through my thoughts about an upcoming solar/battery install I'm planning. Great bloke.... if only he was nearer!

Philip · Apr 2026 Trustpilot

Ian · May 2026 Trustpilot

Sree · May 2026 Trustpilot

Dennis Brown · May 2026 Trustpilot

Tony Deacon · May 2026 Trustpilot

Contacted Ron with a problem and he sorted it out quickly with no problems at all. Very knowledgeable on anything solar/ batteries. I would recommend him to anyone

Phill · May 2026 Trustpilot

I've spoken to Ron a couple of times with issues with my Givenergy installation. Such a friendly knowledge guy very highly recommended. Thank you very much for resolving my issues

michael fairhurst · May 2026 Trustpilot

Mr Machin · May 2026 Trustpilot

Keith Ballard · Apr 2026 Trustpilot

Contacted Solar Tech Support when trying to understand what my Givenergy inverter problem might be and what might be my options. Received good/honest advise which backed up my thoughts.

Hugh Speirs · Apr 2026 Trustpilot

Christopher · Apr 2026 Trustpilot

customer · Apr 2026 Trustpilot

Andy Thomas · Apr 2026 Trustpilot

Philip · Apr 2026 Trustpilot

Upgrades hub Add battery to solar-only Add extra battery GivEnergy expansion EPS installation Inverter replacement Bird mesh

The battery retrofit decision: AC or DC coupling?

For most solar-only systems, the choice comes down to whether you keep your existing inverter (AC coupling) or replace it with a hybrid model (DC coupling).

AC Coupling — recommended for most

✓ Works with any existing solar inverter

✓ Add a battery inverter (GivEnergy AIO, Growatt, SolaX)

✓ Simpler to install — no string rewiring

✓ £2,995–7,000 typical total cost

✗ Slightly less efficient — ~5% conversion losses

✗ Two separate monitoring portals

DC Coupling — if hybrid inverter supported

✓ More efficient — direct solar to battery

✓ Unified monitoring portal for solar + battery

✓ EPS backup power typically included

✗ Must replace existing inverter with hybrid

✗ £7,000–12,000 total cost

✗ DC string compatibility must be checked

In most cases, start with AC coupling. It works with any existing solar inverter, is cheaper, and is simpler to install. Only consider DC coupling if your current inverter is already a hybrid model that supports battery retrofit, or if you are planning to replace the inverter for other reasons and want to combine the work.

AC coupling vs DC coupling — how they work

AC Coupling — how it works

In AC coupling, you install a battery inverter (such as a GivEnergy AIO unit) alongside your existing solar inverter. Both are connected to the AC side of your installation — they each export to your house and grid independently.

Charging: The battery charges from grid (during cheap overnight tariff periods) or from solar excess (when generation exceeds household demand). The battery inverter has its own CT clamp monitoring import/export.

Discharging: When household demand exceeds solar generation, the battery discharges to cover the deficit — reducing grid import.

Compatibility: Works with every solar inverter on the market. No changes to your solar array or existing inverter required.

Typical cost: £2,995–7,000 installed for 5–10 kWh including hardware, circuits, and DNO variation.

DC Coupling — how it works

In DC coupling, the battery connects directly to the DC bus of a hybrid solar inverter. The same unit manages solar generation, battery charging, house loads, and export — no separate battery inverter needed.

Efficiency: Solar energy flows DC-to-DC into the battery without the AC conversion step — approximately 2–5% more efficient than AC coupling.

Control: The hybrid inverter manages all energy flows in real time — smarter than having two independent inverters.

Compatibility: Requires replacing your existing string inverter with a hybrid model (GivEnergy, Sunsynk, Growatt SPH, SolaX, Fox ESS). Not compatible with standard string inverters.

Typical cost: £7,000–12,000 installed — includes the inverter replacement cost.

Is your current inverter compatible with DC coupling?

DC coupling requires a hybrid inverter with a battery port. Most older string inverters do not have this. Check your inverter against the list below.

Hybrid inverters — DC coupling possible

Fronius: Gen24, Symo Hybrid series

SMA: Sunny Boy Storage SM4/SM5/SM6

SolaX: Hybrid G4, X3 Hybrid

Growatt: SPH, SPA series (with ARM firmware)

GivEnergy: AIO (already hybrid — has battery)

Sunsynk: Hybrid 3.6–8 kW

String inverters — AC coupling only

Fronius Symo: Non-hybrid series

SMA Sunny Boy: Standard series

SolaX Mono/Triple: Non-hybrid models

Growatt ShineWay: String inverter

Sungrow SG5K/SG8K: Standard string

Most pre-2018 inverters

How to check: Find your inverter's exact model number (it's on a label on the unit). Search the manufacturer's website for that model. If there is no battery port or battery compatibility listed, it is a string inverter — AC coupling is your option. If in doubt, a system health check includes an inverter compatibility assessment.

Practical considerations before retrofitting

CT clamp repositioning

Your current solar system uses a CT clamp to measure house consumption. When you add a battery, the clamp position may need changing so the battery inverter correctly measures what it should charge from or discharge to. In AC coupling, the battery inverter typically has its own CT — your installer will confirm the correct position during survey. In DC coupling with inverter replacement, the CT is usually repositioned as part of the new installation.

Consumer unit and switchgear

AC coupling requires new circuits from the battery inverter to your consumer unit — new MCBs and typically a dedicated battery isolation switch. Older consumer units may need upgrading to accommodate additional circuits. Budget £500–1,500 for switchgear work depending on your current setup. This is a standard part of any AC coupling installation.

DNO notification — G99 variation

Adding a battery changes your registered installation and requires a G99 variation form to your network operator. This is simpler than a full G99 application and is usually approved automatically within 2–4 weeks. Your installer should handle this. Operating without notifying the DNO technically breaches your grid connection agreement — always confirm the variation has been submitted.

Space and wall mounting

Battery units and inverters are wall-mounted or floor-standing. The battery unit needs clear wall space in a utility room or garage with adequate ventilation and no risk of temperature extremes. For AC coupling, both the existing solar inverter and the new battery inverter must be accessible. Typical GivEnergy AIO units are approximately 600 × 400 × 220mm — similar to a boiler in footprint.

Monitoring setup and tariff configuration

To benefit from cheap overnight electricity (e.g., Octopus Go, Agile), the battery inverter must be configured with a timed charge window that matches your tariff's cheap rate hours. This is done in the battery's monitoring portal (e.g., GivEnergy portal). Your installer should configure this as part of commissioning. If they don't, you will be charging at standard rate rather than taking advantage of time-of-use pricing.

Realistic costs for battery retrofits in 2026

Battery prices have fallen significantly. These are realistic current figures — always get written quotes from MCS-accredited installers.

AC Coupling (5–10 kWh)

Battery inverter + storage unit: £2,500–4,000

Installation labour: £1,000–1,500

Switchgear upgrade: £500–1,000

CT clamp repositioning: £200–400

DNO variation: £0–200

Total typical cost: £4,200–7,100

DC Coupling (Replace inverter + battery)

Hybrid solar inverter: £2,000–3,500

Battery storage unit: £2,500–4,000

Installation (complex): £1,500–2,500

Switchgear / rewiring: £800–1,500

CT clamp + DNO: £200–500

Total typical cost: £7,000–12,000

Notes: Costs vary by region — London and the South-East typically run higher. Always get 2–3 written quotes from MCS-accredited installers. Battery size affects cost — 5 kWh is cheaper than 10 kWh. Finance options are available from some installers. These are estimates only — confirmed written quotes are essential before committing.

Common AC coupling battery options for UK retrofits

These systems are commonly used in the UK for adding battery storage to existing solar-only systems.

GivEnergy All-in-One (AIO)

Battery inverter + storage unit combined in one package. Very popular for UK retrofits. Smart charge scheduling supports Octopus Go, Agile, and other time-of-use tariffs. Available in 2.6 kW / 5.0 kW with up to 19.2 kWh storage. Excellent monitoring portal. Typical installed cost: £2,995–6,500. See the GivEnergy support hub for setup guides.

Sunsynk Hybrid

Sunsynk hybrid inverters can be used for AC coupling in a retrofit scenario. Excellent for time-of-use tariff management. Supports Pylontech and other compatible batteries. UK-based support. Typical installed cost: £2,995–6,000.

Growatt SPH / SPA series

Growatt hybrid units support AC coupling. Available in 3 kW, 5 kW, 6 kW. Supports ShinePhone monitoring and time-of-use scheduling. Compatible Growatt GBLI batteries. Typical installed cost: £3,500–5,500.

Related guides

Add an extra battery

Already have a battery and want to expand? This guide covers adding a second module to an existing hybrid system.

EPS / backup power installation

Adding a battery opens the door to EPS backup. What enabling emergency power supply involves.

Inverter replacement guide

If DC coupling is your preference, inverter replacement with a hybrid model is the first step.

GivEnergy support hub

Setup guides, portal configuration, monitoring setup, and tariff optimisation for GivEnergy systems.

FAQ

Battery retrofit — frequently asked questions

Can I add a battery to any solar system?

Yes — via AC coupling, which works with any existing solar inverter. You add a separate battery inverter (such as GivEnergy AIO) alongside the existing solar inverter. DC coupling, which connects the battery directly to the solar inverter's DC bus, only works if your existing inverter is a hybrid model. Most older string inverters only support AC coupling.

What is AC coupling vs DC coupling?

AC coupling adds a battery inverter alongside your existing solar inverter — both operate independently on the AC side of your system. It works with any existing inverter. DC coupling connects the battery directly to the DC bus of a hybrid inverter — more efficient but requires replacing your existing string inverter with a hybrid model. For most solar-only systems, AC coupling is the recommended starting point.

Will I need a new inverter to add a battery?

Not with AC coupling — you keep your existing solar inverter and add a battery inverter alongside it. With DC coupling, you do need to replace your string inverter with a hybrid model (which is more expensive). For most existing systems, AC coupling is the simpler and cheaper option.

Do I need to notify the DNO?

Yes. Submit a G99 variation form to your network operator. Most variations are approved automatically within 2–4 weeks. Your installer should handle this. Failure to notify technically breaches your grid connection agreement, though enforcement is rare. Always notify — it is required by law and the process is straightforward.

Will adding a battery void my solar warranty?

In AC coupling, no — the battery is independent and your solar inverter warranty is unaffected. In DC coupling, you are replacing the solar inverter, so the old warranty ends and you receive a new warranty on the hybrid inverter (typically 10 years). Check with your original installer or manufacturer if in doubt before proceeding.

Can I retrofit a battery myself?

No. Battery installations involve high-voltage DC circuits, AC switchgear modifications, and grid connection compliance. Only a qualified electrician (Part P certified) should undertake this work. Improper installation can damage equipment, cause fire risk, or breach your insurance. Always use an accredited MCS installer — they are also required for the G99 DNO variation process.

How much does it cost to add a battery to an existing system?

AC-coupled battery systems cost £2,995–7,000 installed for 5–10 kWh of storage. DC-coupled retrofits (replacing inverter + adding battery) cost £7,000–12,000. Costs vary by region, installer, and battery size. AC coupling is usually cheaper and simpler for existing solar-only systems. Always get written quotes from MCS-accredited installers before committing.

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Ready to explore battery retrofit options?

A solar system health check assesses your current inverter, generation profile, consumption patterns, and roof/wall space — then recommends the best battery retrofit approach for your situation. We explain the trade-offs between AC and DC coupling and provide a realistic cost estimate before you commit.

AC and DC coupling options assessed
Health plan from £10/month — realistic cost estimate provided
Inverter compatibility confirmed before any commitment

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