Victron, Huawei, SMA, Tesla or BYD for off-grid and back-up?

Victron fits when the battery must run off-grid, keep three phases on in a power cut, take a generator or grow to a business site. Tesla or Huawei is simpler for a home that wants back-up in short power cuts. SMA suits SMA owners; BYD is only the battery. Our home battery with backup page shows the Victron route.

Three quotes on the table. One says Huawei, one says Tesla, one says Victron, and every installer calls his the best. You want back-up that really works when the street goes dark. And you are not even sure the installers understand their own products.

Most comparisons rank batteries on price per kWh, and that hides the differences that matter. They show up in the first long power cut: how many phases stay on, whether the solar panels keep charging, whether a generator can help. They show up again in year eight, when you want more storage and the system only accepts its own battery.

Our own proof starts close to home. In Zele, a three-phase home has an off-grid mode. When the street loses power, the solar panels and the battery keep working, on 9 kVA and 15.4 kWh.

What is the difference between a battery brand and a battery system?

A battery brand makes the modules that store energy. A battery system decides what happens when the grid fails. BYD Battery-Box is a battery. Victron, SMA and Huawei make the inverters that run a battery. Tesla Powerwall 3 is battery and inverter in one box.

The battery inverter turns battery power into the 230 V your sockets use. It decides how many phases get back-up, how fast it switches over and whether a generator can join. So the inverter, not the battery, answers most questions in this article.

That is why "Victron or BYD" is not a real choice. BYD lists Victron MultiPlus and Quattro models among the inverters for its LVS battery. In Lokeren, the existing solar panels and inverters stayed, combined with a BYD LVS battery of 16 kWh.

Want to see how the Victron parts work together? Our article on how a Victron home battery system works explains the inverter, the GX controller and the VRM app.

Victron vs Huawei, SMA, Tesla Powerwall and BYD: how do they compare?

Victron and SMA Sunny Island are built to run without the grid. Huawei and Tesla are built around the grid, with back-up. BYD depends on the inverter it is paired with. The table puts the makers' own figures side by side.

We checked these values on 26 September 2026 in the makers' own documents. See Victron MultiPlus-II, Victron Quattro, Huawei MAP0, SMA Sunny Island, Tesla Powerwall 3, BYD LVS and the Synergrid C10/26 list. "Not published" means we did not find the value in the maker's documents.

Which home battery systems really work off-grid, not only in a power cut?

Only systems that form their own grid work off-grid for good: Victron and SMA Sunny Island. Back-up means the battery covers a power cut and waits for the grid to return. Off-grid means there is no grid at all, for days or for ever.

Victron writes that the MultiPlus-II and the Quattro "can be used in off grid as well as grid connected" systems. Victron also says not to use its grid-tied mode (ESS) in off-grid systems. SMA sells the Sunny Island for "off-grid systems" too, where it forms the stand-alone grid.

Tesla's system design guide for Powerwall 3 (US edition) is clear: "Powerwall 3 systems must have a grid connection. Fully off-grid systems are not supported." Huawei switches its inverters to off-grid mode when the grid fails, and the LUNA2000-S1 has a black start button. We found no Huawei statement on permanent use without a grid.

How do you recognise a battery that works off-grid in a quote? Our article on which home battery works off-grid lists the signs. If your site has no grid connection at all, see our off grid system.

Which system keeps all three phases running in a power cut?

Victron and Huawei (MAP0 with SmartGuard-T0) keep three phases running in a power cut; Tesla Powerwall 3 in Europe backs up one phase. Tesla's European installation manual has you pick one back-up phase, L1, L2 or L3, and only loads on that phase get power.

Why does that matter? A heat pump, an EV charger or a workshop machine often needs three phases. With one backed-up phase, only the circuits on that phase stay on.

Victron builds three-phase with three units of the same model, one per phase. On a 3 x 400 V house we install three inverters, one per phase. Huawei backs up three phases with the SUN2000 MAP0 and the SmartGuard-T0, which "supports 100% three-phase asymmetric load". Asymmetric (unbalanced) load means one phase carries much more than the others. The older Huawei route, the M1 with a Backup Box-B1, gives single-phase back-up.

SMA offers two routes: three Sunny Island units, one per phase, or one Sunny Tripower Smart Energy. In back-up, the 10 kW Smart Energy delivers 3,330 W per phase, or 10,000 W on three phases.

Weighing a three-phase battery for a heat pump or an EV? Our article on three-phase home batteries with back-up explains the sizing.

How fast does each system switch to back-up?

Victron switches in under 20 milliseconds, and Huawei's SmartGuard can too once its seamless mode is on. Huawei's Backup Box and SMA's home back-up system take seconds. We found no switch-over time for Powerwall 3 in Tesla's European documents.

Under 20 milliseconds is fast enough for computers and other electronics to stay on. That is the UPS function (an uninterruptible power supply, like the small box under an office server). A switch-over of a few seconds is fine for lights and a fridge, but anything without its own battery switches off and starts again.

What a battery with back-up can and cannot keep running is in our article on a home battery with back-up power.

Can you keep your existing SMA, Huawei or SolarEdge inverter?

With Victron you usually keep your existing solar inverter, through AC coupling. AC coupling means the old PV inverter stays and the battery inverter works next to it. Victron writes that it works with "most brands of PV inverters".

The other brands are stricter. With SMA's home back-up, only the Sunny Tripower Smart Energy feeds the back-up grid, not the other PV inverters. Tesla's datasheet shows AC-coupled solar with a Tesla Remote Meter. For Huawei, the documents we could open do not confirm how a third-party inverter joins.

Adding a battery to panels you already have? Our article on adding a battery to an existing SMA or SolarEdge system walks through the checks.

Which system lets you choose your own battery and control it yourself?

Victron lets you choose from many battery brands and control the system locally; Huawei and Tesla keep you on their own batteries. For a technical buyer, that is often the deciding row.

Victron keeps a list of 28 third-party batteries tested with its inverters, BYD and Pylontech among them. The GX controller speaks Modbus TCP and MQTT, runs the open-source Venus OS and can run Node-RED. The VRM portal is free, and Dynamic ESS plans charging on electricity prices and solar forecasts.

Huawei's inverter datasheets list only its own LUNA2000 batteries, and the LUNA2000-S1 has a "third-party dispatch" mode. Powerwall 3 grows only with Tesla Expansion units, and Tesla's design guide says "only Tesla devices are compatible with Powerwall". SMA speaks Modbus and SunSpec, and its Home Storage battery is "ready for dynamic tariffs".

Want to run the battery from Home Assistant? Read our article on Home Assistant with a Victron battery. On a dynamic contract, our article on Victron Dynamic ESS shows how charging follows the price. Our monitoring software page shows what you follow in the app.

Which battery system can grow to a farm or a business?

Victron and SMA Sunny Island scale furthest in power: Victron to 180 kVA with Quattro units, SMA to 300 kW in a multicluster. Tesla Powerwall 3 stops at 4 units and 3 expansions, 44 kW and 94.5 kWh. Huawei's SmartGuard-T0 takes up to three MAP0 inverters.

Scale matters when a home becomes a farm, or a workshop gets a heavy machine. A home-size product then has to be replaced, not extended. BYD grows on the battery side: up to 256 kWh with LVS and 983 kWh with LVL, with a matching inverter.

We build business systems up to 1 MW, modular, with chargers up to 180 kVA on Victron power. In Wingene, a semi-off-grid site delivers 3 x 400 V 63 A from the battery alone, on 45 kVA and 150.4 kWh. In Beveren, a site using 350,000 kWh a year got 200 solar panels and 154 kWh of storage, on 45 kVA.

Our video of a Victron back-up system for an airport control tower shows the same parts at work. For what a Victron system does on a business site, read our article on a Victron system for a business. Our business battery page shows the business route.

What do Synergrid, Fluvius and the AREI inspection mean for your choice?

A battery that runs parallel to the grid must be a model Synergrid has homologated, and it is inspected under the AREI. Synergrid is the federation of Belgian grid operators. Its C10/26 list shows which units meet its C10/11 rules for connection to the grid.

On the list of 21 September 2026 we found Victron MultiPlus-II and Quattro models and Huawei SUN2000 inverters. SMA Sunny Island, Sunny Boy Storage and Sunny Tripower Smart Energy models are on it too. The AREI is the Belgian electrical safety code: a recognised body inspects the installation before use.

In Flanders, you then notify the battery to Fluvius within 30 days after the inspection. In Wallonia, declaring it to ORES is a legal obligation. In Brussels, ask Sibelga before you start. The steps are in our article on how to register a home battery in Belgium.

Victron or another brand: which one fits which buyer?

Choose on what must happen in a power cut and in ten years, not on the brand name. Each of the five has a buyer it suits best.

Victron is not the right choice for everyone. If you only want self-consumption on a small budget, one app and no settings, a single-box battery is simpler. If a small battery is enough, our article on plug-in batteries versus installed home batteries shows the limits. To weigh brands for your own house, compare home batteries on our home battery page.

Which questions should any home battery quote answer?

Every home battery quote should answer five questions in writing, whatever the brand. A good installer answers them without being asked.

Is a group purchase cheaper than a specialist? Our article on group purchase or specialist for a home battery compares the two routes.

How do we build a Victron system that keeps your house or site running?

We size the system on what must keep running, then build and follow it as one partner. These are the steps.

1. Step 1: Measure. We measure your actual and peak consumption over a period, before sizing anything.
2. Step 2: Size and design. We size the inverters, battery and cables on the loads that must stay on, per phase.
3. Step 3: Choose the battery. We check which batteries meet your demands, budget and possibilities, and connect almost all inverter types.
4. Step 4: Install and commission. We build and start the system, with the AREI inspection before use.
5. Step 5: Monitor and support. You follow production, storage and use in the free VRM app, and we can follow the installation remotely.

Our team includes three certified battery experts. We also maintain and repair battery systems that are already installed.