Did you know New Zealand has a surprising number of two-phase properties? For years, they’ve been a real headache for anyone wanting solar. Why? Because most modern inverters were built for single-phase or three-phase setups. Two-phase has been the awkward middle child.
That’s where Sigenergy steps in. Their three-phase hybrid inverters, paired with the Sigenergy Energy Gateway, can happily run on just two phases. In short, they’ve made solar actually work for two-phase Kiwi homes and businesses.
The Problem: Clunky solar and battery setups on two-phase homes
Here’s the reality for most households and businesses with two phases:
- One inverter on one phase → No solar power will go to the other phase, potentially missing out on maximising your solar power.
- Two single-phase inverters → Expensive, messy, and zero balancing between phases.
- AC-coupled batteries (like a Powerwall) → Back up only one phase… unless you fork out for more than one battery.
- Upgrading to a three-phase inverter → Costly, and usually needs modifications or extra equipment.
Basically, you either paid too much, lost functionality, or accepted a half-baked backup setup. Not ideal.
How It Signergy Works For 2 Phase Properties
Normally, a three-phase inverter expects to be connected to three active phases. In a two-phase setup, one phase is missing. The Sigenergy system recognises this during commissioning and automatically adjusts.
Here’s how it works:
- Automatic detection – During commissioning, the inverter realises the third phase isn’t there and reconfigures itself.
- Safe limits – Power is capped at two-thirds of the rated capacity to protect the electronics. For example, a 15 kW inverter will run at a maximum of 10 kW on a two-phase supply.
- Balanced output – The system shares power safely between the two active phases, preventing uneven loading.
This gives properties with two-phase supply access to high-quality solar and storage technology that would otherwise be off-limits.
The Extra Benefit: Unbalanced Output
Sigenergy has also designed their inverters with strong “unbalanced output” capability. In plain English, that means each phase in a two- or three-phase system can independently deliver up to 100% of its share of power, with an extra 10% headroom on top.
For example, with a 25 kW three-phase unit:
- Each phase can normally deliver 8.3 kW.
- With Sigenergy’s design and paired with a battery, each phase can handle up to 9.17 kW.
This flexibility is useful where household or commercial loads aren’t evenly spread across all phases.
Why Unbalanced Output Isn’t the Full Fix for New Zealand
While unbalanced output feature, they don’t completely solve New Zealand’s biggest issue: the lack of net metering. Without net metering, Kiwis can’t simply offset electricity exported on one phase against consumption on another. This means that even with advanced unbalanced output, customers may still lose value when solar power is exported unevenly across phases.
As I’ve written about before in this blog post, the real solution would be regulatory change to allow net metering across phases. Until then, technologies like Sigenergy’s make life easier, but they don’t remove the underlying limitation.
Takeaway
Sigenergy deserves credit for tackling two stubborn problems:
- Bringing three-phase inverters to two-phase properties.
- Allowing flexible unbalanced output for uneven household loads.
For solar customers, this opens the door to larger solar and battery systems that were previously impractical. But let’s be clear – until New Zealand sorts out net metering, even the smartest inverter tech won’t unlock the full potential of solar for multi-phase homes.
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