The system at a glance
Robbert's home battery project is a three-phase Victron setup designed to carry the household for several days off-grid. The headline numbers:
- 3x Victron MultiPlus-II 5 kVA inverter/chargers
- 48 kWh of total storage (3x 16 kWh DIY LiFePO4 packs)
- 314 Ah prismatic cells in 16S configuration per pack
- JK BMS per pack (150 A, RS485 to Victron)
- Three-phase wiring: one Multiplus per phase
- Solar input on the AC side, not the DC side
This video pulls the whole project together: the mounting board, the Multipluses, the meter cupboard, the home-grown Lynx Shunt that replaces a €300 Victron unit with €100 of parts, and the comment-driven changes that came out of viewer feedback.
The mounting board
Before bolting anything to the wall, Robbert sketched the full layout on the plywood backing and packed components as tight as the cable runs allowed. Shorter cables mean lower losses. The board sits against the wall with heavy bolts straight through into masonry, because the Multipluses are too heavy to hang from wood alone.
Wiring trunking is 40x60 mm slot-sided trunking, with break-out fingers along the edges. Cables drop out anywhere on the run without drilling, and T-junctions are made by snapping out the fingers. Custom 3D-printed end caps in Victron RAL 7012 grey fill the gaps where cables exit toward the wall.
Each Multiplus is mounted permanently via the four rear holes, with the bolts passing through the plywood into the masonry. Less convenient to service than the supplied bracket, but it isn't going anywhere.
The meter cupboard
Supply enters the meter cupboard, hits the main breaker, then detours through the shed (where the Victron lives) and comes back to the original household groups. Four added components: an extra RCD on the cable to the shed (a main breaker can't legally feed a sub-distribution board directly), a second main breaker inside the shed for isolation during service work, a 25 A breaker on the return leg, and a planned bypass switch to route around the Victron entirely.
Cable between meter cupboard and shed: 5x6 mm² flex, two runs of ~5 m. Well inside the 25 A rating for 6 mm² over 70 m.
The neutral wiring took a comment-driven correction. The first cut daisy-chained all three Multiplus neutrals off the supply neutral. The right pattern is to split the supply neutral at a terminal block and run a separate conductor to each Multiplus, same on the AC output side. Robbert redid it on camera for the next video.
Why three 5 kVA units instead of one 3 kVA
The MultiPlus-II 3 kVA can charge the battery at 35 A. On a 48 V pack that's ~1.7 kW of solar pull-through. The 5 kVA can charge at 70 A, ~3.3 kW.
Robbert's setup has ~3 kW of solar on each phase (panels on the Droomvlucht veranda, the main roof, the back-garden veranda, and the front of the house). On the 3 kVA, half the midday solar peak would have to be exported to the grid because the inverter couldn't push it into the battery fast enough. On the 5 kVA, all of it lands in the battery.
The economics are downstream of the export rate. With the Dutch net-metering changes, exporting solar at midday is worth less than storing it and discharging it in the evening. A smaller inverter that forces export defeats the point of the battery.
Solar on AC, not DC
Robbert keeps the existing AC-coupled solar inverters instead of replacing them with Victron MPPTs. An MPPT is more efficient (one fewer DC/AC conversion), but used AC inverters cost €50-60 on Marktplaats, the cable runs are easier, and the panels still produce during a blackout if wired to AC1. At his solar capacity, the efficiency gain doesn't pay back the MPPT delta.
The DIY Lynx Shunt that saves €200
The Victron Lynx Shunt is ~€300. Robbert builds a functional equivalent for ~€100:
| Part | Cost |
|---|---|
| Victron SmartShunt | €89 |
| Custom 3D-printed housing (RAL 7012) | €3 plastic |
| 30x8 mm copper busbar (~15 cm) | €28 |
| Class T fuse | €50 |
| Cell connectors | €10 |
| 500 A battery disconnect switch (optional) | €10-30 |
Two configurations. A: through-busbar across the top, SmartShunt below, optional Class T in the middle. Best for high-current setups, which is what Robbert uses. B: SmartShunt below, 500 A disconnect above, plus a precharge button: a momentary switch routes battery voltage through a 24 V incandescent bulb (acting as a current-limiting resistor) so the Multiplus capacitors charge before the main contactor closes. No arc, no welded contacts.
The Lynx Power In gets the same DIY treatment. Adding €5 of bolts, washers, nuts, and four MEGA fuses turns the €120 Power In into the functional equivalent of the €200 Distributor. The only thing missing is the LED board that flags a blown fuse to the Cerbo, which the Multiplus surfaces anyway.
The battery packs
Each pack is 16 cells (EVE MB31, 314 Ah) in 16S, giving ~51 V nominal and ~16 kWh. Cells are arranged 4-wide x 4-deep on their flat sides, with threaded rod through each row to keep them compressed. LiFePO4 cells expand and contract through charge cycles, and compression slows long-term swelling.
A 150 A JK BMS sits on a 3D-printed bracket on the side of the pack. Balance leads run to every cell. Heavy current cables run from the first cell's negative and the last cell's positive through 100 A fuse holders to the pack's external terminals. The 100 A working ceiling is below the cells' 157 A 0.5C limit and easier on the BMS. Three packs in parallel: 300 A continuous, ~14 kW out.
The original MEGA fuses are scheduled for an Adler EF3 swap: same footprint, but 50,000 A AIC instead of 2000, which is what a 314 Ah cell short actually demands.
Takeaways
- Three 5 kVA Multipluses cost more than three 3 kVA units but pay back through higher solar charging rates: ~3.3 kW per phase versus ~1.7 kW.
- A used AC solar inverter at €60 still beats a new MPPT on payback math when the solar capacity is modest.
- DIY versions of the Victron Lynx Shunt and Distributor cut roughly €200 off the system price without losing safety, as long as the Class T or EF3 fusing is correct.
- Always split shared neutrals at a terminal block rather than daisy-chaining them between inverters.
- The MEGA fuse is the trap on a DIY LiFePO4 pack. AIC is the spec to check; EF3 is the same footprint with 25x the interrupt rating.
