You can install a home battery yourself. But a recognised body must inspect the result under the AREI before you use it and before Fluvius accepts it. Inspectors reject missing diagrams, unapproved inverters and back-up circuits that are not protected on battery power. A plug-in kit is the easy part. A whole house on back-up is a job for someone who knows batteries.
You are handy, you wired your own garage, and the parts are online: a Victron inverter, a rack of LFP modules, some cable. One Dutch-speaking owner put it simply on a DIY forum: "Is dit zo een klus?" In Flanders, another owner installed his batteries himself. Fluvius told him no inspection was needed. A year later a letter asked him to register the battery at once, and the online form would not accept it without an inspection report.
That is the hidden cost. A home battery that fails the inspection cannot be registered, and you cannot simply use it and wait. The inspector returns only after the faults are fixed. Redrawing the diagrams, changing a changeover or replacing an unapproved inverter costs more than doing it right the first time. And with a full back-up, a mistake shows up in the worst moment: during a power cut.
In a home in Peer the customer is an electrician himself. We specialise in battery technology, and together that made a fine finish. The whole house is on no-break: when the grid fails, every device keeps running, with 5 kVA and 15.4 kWh.
Are you allowed to install a home battery yourself in Belgium?
The Belgian rules do not ask who did the work; they ask whether the result is conform. Every new installation, and every major change such as adding a circuit, must be checked by a recognised inspection body before you use it.
That check comes from chapter 6.4 of the AREI, the Belgian electrical safety code (Book 1). The FOD Economie lists when a household installation must be inspected. That is before use, for each major change or extension, when the connection is reinforced, at the sale of a home, and periodically.
The grid operator adds its own conditions. According to Fluvius, a battery up to 25 kW may only be connected when two things are true. A recognised body has declared it conform under the AREI, and it meets the Synergrid technical rules. The inverter power is limited to 5 kVA on a single-phase connection and 25 kVA on a multi-phase one. The imbalance may be at most 5 kVA per phase.
The route for a home battery you install yourself
Registration itself has its own guide: how to register a home battery in Belgium, with the Synergrid list and the inspection step by step.
What does the inspector check on a home battery?
The inspector checks the documents, looks at the installation, and tests and measures it, all on site. For a home battery the documents are where many DIY jobs already go wrong.
| What | What the rules ask | Source |
|---|---|---|
| Single-line diagram | Every circuit, protection and RCD, and the sources: solar panel, inverter, battery | FOD Economie |
| Situation plan | Where the boards, the fixed appliances and the sources are | FOD Economie |
| Insulation | At least 500 kOhm per circuit at a 500 V test | AREI 6.4.5.1 |
| Solar part up to 10 kVA | Marked DC and AC conductors, warning signs, earthed panel frames | AREI 7.112 |
| Grid failure test | The separation opens within 5 seconds without grid voltage; no solar power to the grid until it returns | AREI 7.112 |
| RCD test | Tested with its own test button and with a real fault current | AREI 7.112 |
The warning signs are specific. Near the solar installation the AREI asks for "Do not disconnect under load" and "Electrical installation always live", or an equivalent text. The report lists the number, type, serial number and maximum AC power of each inverter.
After the inspection the owner gets the report. If the installation is not in order, you fix the faults and have it inspected again. The drawings and reports go into the file of the installation, which is kept in two copies.
What does the AREI inspector reject on a home battery you install yourself?
Owners who went through it report the same refusals again and again. Most of them follow directly from the rules.
| Refused | Why | How to avoid it |
|---|---|---|
| Inverter or battery not meeting the Synergrid rules | Fluvius only connects storage that meets them; one forum owner failed on his inverters and traction batteries | Choose an inverter that is on the Synergrid list before you buy |
| Battery box built from loose cells | Inspectors report anything from a straight no to a request for CE declarations of cells, BMS and case | Use a complete battery with its documents |
| Back-up output without its own protection | Protection against electric shock must also work when one source alone feeds the circuits | An RCD on the back-up side, sized for battery power |
| Changeover that can connect two sources | Switching devices must act on all live conductors and may not put sources in parallel at the wrong moment | A proper changeover or an inverter with a built-in transfer |
| Diagrams missing the battery | The single-line diagram must show the sources | Draw the battery, inverter and back-up board before the visit |
| Missing signs or marking | The AREI asks for them on the solar part | Put them on before the visit |
A community forum thread on a DIY three-phase system in Flanders shows how it goes. One member saw no way to get a home-built battery box approved. Another chose factory-made batteries with their documents and had them inspected. The difference was not skill. It was documents and approved equipment.
Tip
Before you buy, ask the inspection body what it wants to see for your battery and inverter. It costs one phone call and can save a second visit.
Is a home battery with full back-up harder to install yourself?
Yes, because in a power cut the battery becomes the only source, and the whole installation must stay safe on it. A battery that only stores solar power is simpler than one that carries the house.
An inverter delivers far less short-circuit current than the grid. A breaker that trips fast on the grid may react slower on battery power. That is why forum builders choose their breakers and RCDs for the back-up side on purpose, and why the inspector looks at that side separately.
A large home adds more. Three phases, a heat pump and an electric car mean more power and limits per phase. Above 10 kVA of storage on three phases, Synergrid C10/11 no longer treats it as a small installation. Our guide to a three-phase home battery with full back-up explains what that means per phase. The three levels of back-up are in our guide to a home battery with backup power.
What happens to the warranty and your insurance?
Read the warranty terms before you start: many link the warranty to a correct installation and commissioning. Your insurer, in turn, may ask for the inspection report after a fire.
SMA is an example. Its storage warranty runs two years and can be extended to ten when the system is registered within 30 days with a commissioning report. Changes without the manufacturer's approval are excluded. Other brands have their own terms, so check the ones for your battery.
Buying loose parts online? Under the EU Battery Regulation a home battery counts as a stationary battery energy storage system, whoever uses it. Since 18 August 2024 it must be tested for safety and keep state-of-health data in its BMS. From 18 February 2027, every battery above 2 kWh placed on the market or put into service needs a digital battery passport. Ask the seller for the documents; the inspector may ask you for them too.
DIY, an electrician or a battery specialist: who does what?
You can split the work, as long as someone takes responsibility for the whole system. In Peer, the customer is an electrician and we brought the battery technology.
Doing it yourself works when
- you only add a battery to a simple set-up
- you choose approved, complete equipment
- you draw the diagrams and book the inspection before use
- you accept that faults mean a second visit
A specialist makes sense when
- the whole house must run on back-up
- you have three phases, a heat pump or an EV
- the system must switch within milliseconds
- you want the warranty and the inspection to be one story
Our verdict
A plug-in battery or a simple storage battery is a fair DIY project for a skilled owner. A full back-up in a large home is a system, and the inspector judges it as one.
Are you an electrician yourself? Our article on working with a battery specialist explains how the work is usually split. Want to compare with a plug-in model? See our plug-in battery or installed home battery guide.
Planning to do part of the work yourself? Tell us what you have and what must keep running.
How do we build a home battery with full back-up?
We measure first, then connect your important systems to the battery, so the house keeps running when the street fails. Our team has three certified battery specialists.
- Step 1: We measure your consumption and your connection before we design anything.
- Step 2: Together we decide which systems and appliances must keep running.
- Step 3: We connect a new battery, or revise an existing one. We can connect almost any type of solar inverter to the home battery.
- Step 4: When the grid fails, the inverter takes over within 20 milliseconds, fast enough for computers. You follow everything in the free VRM app and portal.
Our home batteries come with a 10-year warranty on retained power, and we also maintain and repair existing battery systems. See what our home batteries with back-up can do, or look at the no-break home in Peer.
Frequently asked questions
Can I do the inspection of my home battery myself?
No. The conformity check before use is done by a recognised inspection body. The FOD Economie publishes the list of recognised bodies.
Do I need a new inspection when I add a circuit for the back-up?
Yes. Adding a circuit is a major change, so it must be checked before use. The check covers the change and its effect on the rest of the installation.
Must Fluvius know about a battery I installed myself?
Yes. Since 1 January 2017 every grid user must report a storage system. Below 25 kVA you do it in Mijn Fluvius, with the inspection report.
Does an off-grid system need an inspection too?
Yes. The AREI check before use also applies to installations fed by a private source. Our guide to the off-grid installation inspection explains the details.
Want a full back-up that passes inspection the first time?
Tell us how your house is connected, what must keep running and what you plan to do yourself. One of our battery specialists will tell you what the system needs.
Sources
- FOD Economie: AREI Book 1, installations on low and very low voltage (2026)
- FOD Economie: inspection of household electrical installations
- FOD Economie: types of inspections of household installations
- Fluvius: report a storage system
- Synergrid: technical prescription C10/11, edition 2.4
- SMA: warranty terms for storage systems
- EUR-Lex: Regulation (EU) 2023/1542 on batteries