The question Robbert keeps getting
Earlier videos in the series cover building a 16 kWh DIY pack for around €1,500. The comments came back with the same follow-up: a pack is not a working home battery, so what does the rest of the installation actually cost? Robbert kept the answer out of the build videos on purpose. The full price depends on whether the house has one phase or three, whether the panels produce 1 kW or 12 kW, whether an EV needs to charge at home, and which inverter brand the owner already has parts for. A single sticker price would mislead more people than it helps. This video gives three concrete reference setups so the math is visible.
Setup 1: the cheap end, single 3 kVA Victron
The minimum viable installation for a low-consumption household with a small solar array.
| Part | Price |
|---|---|
| DIY 16 kWh LiFePO4 pack (case, BMS, EVE cells) | €1,500 |
| Victron MultiPlus 3 kVA inverter/charger | €514 |
| Victron energy meter for the meter cupboard | rest |
| Total | €2,378 |
The MultiPlus is an inverter and a charger in one. It uses grid voltage to charge the pack and uses the pack to push power back into the house. A current-transformer energy meter clamps onto the live conductors after the main breaker and reads how much power is flowing in or out of the grid. That measurement goes to the inverter so it can match the load: 500 W exporting becomes 500 W charging the pack, and net grid draw stays close to zero.
Throughput limits for this setup: 100 W of grid-to-pack charging and 2,400 W of pack-to-house discharge. With a 3 kW solar array on the roof, the small charging window means roughly 1,300 W will still export to the grid even on a sunny day. For a household with few panels and modest consumption that is enough. Below €2,400, 16 kWh on the wall.
Setup 2: 5 kVA Victron for a normal solar roof
When the array is bigger than the inverter can absorb, the next step up makes sense.
| Part | Price |
|---|---|
| DIY 16 kWh LiFePO4 pack | €1,500 |
| Victron MultiPlus 5 kVA | ~€1,064 |
| Total | €2,564 |
The 5 kVA unit can charge at 3,300 W and discharge at 4,000 W. A 3 kW solar array now lands fully in the battery instead of leaking back to the grid, and a 2,000 W dishwasher plus normal household loads still come straight off the pack. Loads above 4 kW pull the balance from the grid, with the pack always taking priority.
Setup 3: three-phase, three MultiPlus units
Three-phase homes do not need three inverters by default. The energy meter sees all three phases. A single MultiPlus on one phase can keep the total grid draw at zero, because the meter knows which phase is exporting and which is importing.
The reason to scale up is power, not phase coverage. Charging an EV at 11 kW pulls more than any single MultiPlus can supply. Three 5 kVA units in parallel give 12 kW of combined discharge, which is enough to feed an 11 kW car charger and still leave 1 kW for the kitchen.
| Part | Price |
|---|---|
| 3 × DIY 16 kWh packs (48 kWh total) | €4,500 |
| 3 × Victron MultiPlus 5 kVA | ~€3,192 |
| Cerbo GX (system controller) and cabling | rest |
| Total | €3,964 (Robbert's quote for the inverters + small parts on top of the packs) |
All three MultiPlus units connect to the Cerbo GX over VE.Bus so the controller can assign charge or discharge per inverter.
Backup-power wiring as a bonus
In setups 2 and 3 there is an alternative wiring that removes the external energy meter entirely. The grid feed is routed through the MultiPlus AC input, and the house circuits feed off the MultiPlus AC output. Each inverter has internal current sensors, so the system already knows what is flowing in and out.
The payoff: when the grid drops, the inverter detaches from the AC input within milliseconds and the AC output keeps running. The house stays powered, including any solar inverters wired into the meter cupboard. The pack charges from rooftop solar in island mode and the lights stay on.
The safety detail Victron handles correctly: a physical relay opens the AC input the instant the grid voltage disappears, so no power leaks back up the street while a utility engineer is working on the line. Anyone running this kind of installation should test that disconnect on commissioning and verify there is no voltage on the grid side during island mode.
What the price comparison looks like against a plug-in battery
A popular plug-in unit gives 2.5 kWh of storage for €1,213 and discharges at 800 W. Three of them cost roughly €3,640 for 7.5 kWh. Setup 1 above is 16 kWh for €2,378. The DIY route delivers more than twice the storage for less money, with the trade-off being the labor of the build itself.
Caveats
- Insurance varies. Some Dutch insurers require certified packs, some require a registered installer, some do not care. Check with the policy before building.
- Anything after the main breaker is legal for a homeowner to install in the Netherlands. Anything before it is electrician territory.
- A pack is not a return-on-investment device. The payback math on home batteries is long. Treat the install as a comfort and resilience upgrade.
- 16 kWh nameplate is not 16 kWh usable. Plan for around 70 percent depth of discharge so the cells stay healthy. The same rule applies to any home battery, including plug-ins.
Takeaways
- A working home battery is at least a pack plus an inverter plus a way to read the grid. Without all three it does not balance loads.
- Three reference price points to anchor a build: ~€2,400 for the small single-phase setup, ~€2,600 for the bigger single-phase setup, ~€4,000 inverters on top of three packs for the three-phase 48 kWh build.
- Routing the grid through the AC input of the MultiPlus turns the install into backup power for free, including for any rooftop solar already in the meter cupboard.
- Brand choice is not about sponsorship. Victron is modular, so a single inverter today can become a three-phase, three-inverter system later without replacing what is already on the wall.
