Victron Meter Cupboard Setup Follow-Up and Viewer Q&A

Steps

1. 1

   Step 1: Meter cupboard setup and transfer switch

   I come from the main switch, go through a residual current circuit breaker, and feed the Victrons. From the Victrons, I return through a 35-amp fuse and feed my RCD. A transfer switch is not installed yet, but I will place it in the extra box next to my standard meter cupboard.

   What I used

   Item	Amount	Notes
   Residual current circuit breaker	1	Feeds the Victrons
   35-amp fuse	1	Protects the return from the Victrons

2. 2

   Step 2: Using standard tools

   Some viewers noted that I do not always use the most ideal tools. I used what I had on hand, mainly my favorite Fluke multimeter which I use for all projects. While there are better and less error-prone meters, my standard multimeter was good enough for the job.

   What I used

   Item	Amount	Notes
   Fluke multimeter	1	Used for standard electrical checks

3. 3

   Step 3: Performing the 10-point measurement

   Jaap pointed out that to properly prove a setup is de-energized, you must use the 10-point measurement. I previously only measured between neutral and each individual phase. If phase 3 and neutral were disconnected while phase 2 and 3 remained connected, measuring between phase 2 and 3 would show 400V, so the 10-point check is a great tip.

   Tip

   Use the 10-point measurement to properly prove a system is completely de-energized.

4. 4

   Step 4: Explaining AC-in, AC-out 1, and AC-out 2

   AC-in works as both an input and output, and AC-out 1 and 2 do as well but serve different functions. AC-out 1 always has power whether connected to the grid or running on backup power. AC-out 2 only has power when grid power is present.

5. 5

   Step 5: Managing heavy loads with AC-out 2

   I connected my whole house to AC-out 1, but heavy appliances like heat pumps, washing machines, and dryers can quickly drain the battery during a power outage. By moving large power consumers to AC-out 2, they automatically shut off when the grid fails. This keeps only the important appliances running on backup power.

6. 6

   Step 6: Solar panels on AC-out 1 without a separate meter

   You do not always need an extra power meter when connecting solar panels to the Victron output. The Multiplus has a built-in energy meter on every phase. It measures how much power goes from the grid to the house and back, eliminating the need for a separate solar meter.

7. 7

   Step 7: How Multiplus handles zero-feed-in and power balance

   When solar panels produce 1000W and the house uses 300W, the remaining 700W flows back through the Multiplus. The Multiplus sees this and uses that 700W to charge the battery pack instead of feeding it to the grid. It similarly decides whether to draw 500W from the grid or the battery based on household usage.

8. 8

   Step 8: Backup power and solar inverters during outages

   Normally, solar inverters shut down when the grid fails for safety reasons. By hanging my solar inverters on AC-out 1, they stay powered during a grid outage. The Multiplus absorbs the returning solar power to charge the batteries since it is now disconnected from the net.

9. 9

   Step 9: Minimizing grid draw and the 50W buffer

   Rick asked how to get grid draw as close to zero as possible. The Victron cannot sit at 100 percent zero because minor fluctuations and inverter reaction delays would cause constant switching between charging and discharging. To prevent this inefficiency, Victron standardly draws about 50W from the grid.

10. 10

    Step 10: Energy storage versus energy trading

    The Victron can work in two ways: as an energy storage system to save solar power for later, or for energy trading. Energy trading charges the batteries during low tariff hours and discharges them when prices are high. However, trading shortens battery lifespan, so you must balance the costs.

11. 11

    Step 11: Frequency shifting for inverter control

    Bob asked if the PV on AC-out is well-tuned. When the grid fails, the Victron takes over at 50 Hz. To communicate with solar inverters during backup mode, the Victron uses frequency shifting, moving from 50 Hz up to 53 Hz to signal when battery packs are nearly full and the inverter needs to slow down or shut off.

12. 12

    Step 12: Grid isolation relays and switching sounds

    Herman asked how to prevent power from flowing back into the grid during an outage. The Multiplus has internal relays on AC-in that physically disconnect the system from the grid when grid power fails. The clicking and rattling sounds heard when shutting off the main switch are these relays opening and closing.

13. 13

    Step 13: Emergency stop setup for the fire department

    Gerk-Jan and Iskom noted that firefighters expect the house to be dead when the main switch is off, which is not true with a battery backup system. The Victron units have a built-in factory contact wire bridge at the bottom. Breaking this loop shuts down the Multiplus immediately so it can no longer supply power.

14. 14

    Step 14: Installing serial emergency stop buttons

    I am pulling a cable from the Multiplus to the meter cupboard and the shed to install emergency stop buttons wired in series. Pressing either stop button will break the loop and shut down all Multiplus units instantly. This ensures everything can be completely shut off in case of a fire.

15. 15

    Step 15: Victron rule 1.0 on PV output and battery capacity

    Roger asked if I meet the Victron 1.0 rule, which states maximum PV output must equal or be less than the VA rating of the inverters, and requires 4.8 kW of battery capacity for every 1.5 kW of PV. I use a 5 KVA inverter per phase with about 3 kW of solar per phase, keeping me under rule 1.0.

    What I used

    Item	Amount	Notes
    5 KVA inverter	3	One per phase

16. 16

    Step 16: Expanding battery capacity and solar layout

    I currently have one 16 kWh DIY battery pack and two of three solar strings connected, which exceeds the max 5000W charging limit slightly so excess goes to the grid. The system is built for three battery packs totaling 48 kWh, which I expect to add within a couple of months. I also plan to expand to 45 total solar panels across my house and veranda to maximize generation in spring and autumn.

    What I used

    Item	Amount	Notes
    Battery pack	1	Current 16 kWh, expanding to 48 kWh
    Solar panels	45	Total planned across house and veranda

17. 17

    Step 17: Rebuilding the messy meter cupboard

    Maarten Kromhout commented that my meter cupboard looks messy due to years of added groups for extra power and induction cooktops. Once everything is working and adjusted, I plan to completely empty the meter cupboard and rebuild it neatly with properly organized cables.

18. 18

    Step 18: Experimenting with a DIY hoverboard wind turbine

    I am experimenting with wind energy to generate 100 to 300W at night or in winter using cheap hoverboard BLDC motors. I modified a 350W motor with 3D-printed hubs and 12 shorter blades to act as a generator. This proof-of-concept wind turbine costs very little to build and lets me experiment with DIY wind power.

    What I used

    Item	Amount	Notes
    Hoverboard motor	1	350W BLDC motor used as generator
    3D printed parts	1	Hubs and 12 blades

19. 19

    Step 19: Rooftop duct wind turbine concept

    I am working on another proof-of-concept design that sits on top of a solar panel. It uses the wind blowing over the roof and channels it through a front opening with a ratcheting wheel inside to generate extra energy. I want to test if this design is viable and what the payback period would be.

20. 20

    Step 20: Adding an Arduino for cell-level temperature safety

    To improve safety beyond standard total pack monitoring, I plan to connect an Arduino with 16 individual temperature sensors glued to every single cell. If any cell exceeds 60 degrees Celsius, the Arduino will instantly trigger the emergency stop loop and shut down the entire system.

    Warning

    Cells must never reach 60 degrees Celsius; shut down the system immediately if this temperature is hit.

    What I used

    Item	Amount	Notes
    Arduino	1	Controls cell temperature safety cutoff
    Temperature sensors	16	One attached to each battery cell

21. 21

    Step 21: Takeaways

    • Always use thorough methods like the 10-point measurement to verify circuits are de-energized.

    • Victron systems maintain a small 50W grid draw to prevent inefficient constant switching.

    • Frequency shifting allows the Victron to communicate with solar inverters during backup mode.

    • Emergency stops must be wired in series to completely shut down backup power systems for safety.

    • Adding cell-level temperature monitoring with an Arduino provides an extra layer of fire protection.