Mangawhai, Northland. Commissioned March 2024, two-year results compiled July 2026 by MEDA Off Grid + Solar Solutions.
This home had a perfectly good grid connection. The owners switched it off.
Most off-grid projects start with a problem: a remote site, a six-figure lines quote, no power at the gate. This one did not. When the owners of this large Mangawhai property planned their new home, the grid was right there, connected and working.
They disconnected it anyway.
What they wanted was simple to say and hard to build: complete energy independence. No reliance on a power company, no exposure to price rises or outages, no bill, ever. Their own power station, running their whole life, including a pool, on full three-phase supply, with nothing coming in from the street.
Two years on, the numbers say it worked.
- 23,600 kWh generated in the last 12 months, around 65 kWh every single day
- 99% of the home's power came straight from the sun. The backup generator supplied just 162 kWh all year, less than 1%
- The home uses nearly three times the power of a typical NZ household, and makes all of it on site
- Full three-phase supply to a large family home, pool and all
The hard part was not the install. It was the design.
A system this size does not come off a shelf. Before a single component was ordered, this project went through months of design work: load analysis of a genuinely big household, array sizing driven by the worst month of winter rather than the best day of summer, storage sized so a run of grey days is an event the family never notices, and round after round of engineering back and forth to get every detail right.
The 150kWh battery bank was engineered with the battery manufacturer directly: 30 lithium modules across three purpose-built cabinets, on a single supervised communications chain, with the factory's own drawings behind the layout. The solar is split across two ground-mounted arrays on four independent charge controllers, so no single fault can take the whole array down. Three inverters share the load in three-phase configuration, and every cable, breaker and busbar in the system is sized, documented to New Zealand standards, inspected and certified.
That is what buying independence actually looks like: not bigger gear, better design.
The system
One of the largest residential off-grid systems we have built:
- Solar: 72 x Jinko 415W Tiger panels (29.9kW) on two ground-mounted arrays, positioned for all-day sun
- Storage: 150kWh Dyness lithium bank, 30 modules across three engineered cabinets
- Inverters: 3 x Victron Quattro 10kVA in three-phase configuration (30kVA total), 230/400V supply just like the grid, without the grid
- Charge control: 4 x Victron SmartSolar MPPT 250/100 charge controllers
- Monitoring: Victron Cerbo GX with full remote monitoring, visible to us in Tauranga and to the owner from a phone
On a clear day the array pushes over 21kW into the battery bank. We have watched it charge all 150kWh before lunch.
Two winters of proof
Winter is where off-grid designs are honest or they are not. Through two full winters this system has asked the backup generator for about 1% of the home's energy, a few dark weeks in the depths of June, exactly as the design intended. The other 99% came off the roof of the paddock, silently, while the family lived exactly as they would on the grid.
We still watch it from our Tauranga workshop through remote monitoring, and the owner checks it from a phone. Mostly, there is nothing to see. That is the point.
Thinking about owning your power?
Whether it is a tiny home or a property like this one, the design process is the same: understand the loads, size it honestly, build it properly. Talk to us before you buy anything.
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