I'm building my own home battery: what's in it and what I'm learning
Menno, the developer of Thuisbord, is building a 32 kWh home battery with Victron parts. What's in it, why, and what does it mean for Thuisbord?
I'm Menno van Hout, the developer of Thuisbord. Alongside my work on the app, I'm working on something big at home: my own home battery, built from individual components. In this post I show what's in it, why I'm doing this and what it means for Thuisbord.
Why a home battery
A home battery stores electricity so you can use it later. For example, electricity from your solar panels that you don't need during the day, or electricity you buy at a moment when it's cheap.
That becomes more interesting now that the salderingsregeling (net metering) is ending. Net metering means you can offset the electricity you feed back to the grid against the electricity you take from it. The scheme ends 1 January 2027. After that, it's often more worthwhile to use your own electricity yourself than to feed it back.
On top of that, more and more households have a dynamic energy contract. With one, the electricity price changes every hour. A battery can charge when the price is low and discharge when it's high.
Whether a home battery pays off for your household depends heavily on your usage, your contract and the purchase price. For me it's also a learning project: I want to understand exactly how a system like this works.
What's in my setup
I'm using components from Victron Energy, a manufacturer of inverters and control equipment, and battery packs from Dyness. Here's the list:
| Component | Quantity | What it does |
|---|---|---|
| Dyness Powerbrick PLUS | 2 | Battery packs, 32 kWh of storage together |
| Victron MultiPlus II 6K5 | 3 | Inverter and charger, from 48 V to 230 V |
| Cerbo GX | 1 | The central brain of the system |
| GX Touch, 5 inch, with wall bracket | 1 | Screen for viewing the system |
| Lynx Distributor | 2 | Distribution of the direct current |
The battery packs
The two Powerbricks store 32 kWh together. For comparison: an average Dutch household uses about 6,8kWh per day. How much of that is actually usable depends on how deeply you let the battery discharge.
The inverters
The batteries work with 48-volt direct current. In your home you use 230-volt alternating current. The MultiPlus II converts one into the other, and can also recharge the batteries from the grid. I'm using three, one per phase of my three-phase connection. Each delivers about 6000 W.
The Cerbo GX and the screen
The Cerbo GX collects all data from the batteries and inverters and controls the system. The small GX Touch screen on the wall shows what's happening: how much is in the battery, and what is being charged or discharged.
The Lynx Distributors
Thick cables carrying high currents run between the batteries and the inverters. The Lynx Distributors are distribution blocks with fuses, so those currents are distributed neatly and safely.
An honest note about safety
A battery of this size works with high power. Mistakes in wiring or fuses can be dangerous. I don't recommend anyone do this themselves without knowledge of electrical engineering. Leave the connection to your meter cupboard to a certified installer, and check what your insurance requires.
What this means for Thuisbord
Because I work with a battery myself, I'm working on support for home batteries in Thuisbord. The idea is that you can see what the battery is doing on the shared screen at home, alongside your usage and today's and tomorrow's electricity prices. When that will be ready is not yet fixed.
One thing won't change: Thuisbord only reads. It never switches or controls a device, so no battery either. You leave that to your own system, such as the Cerbo GX or your Homey or Home Assistant. The data comes in through your own Homey or Home Assistant, after you give permission for that.
In a future post I'd like to write more about what I learn from the first months with this battery. If you want to stay up to date on Thuisbord, you can join the waitlist at thuisbord.app.
Sources
- Victron Energy, product information MultiPlus II, Cerbo GX, GX Touch and Lynx Distributor.
- Dyness, product information Powerbrick PLUS.
- Rijksoverheid (Dutch central government), information on phasing out the salderingsregeling.