Generator for your solar PV system: how SPARK 2-Wire remote start works and why every battery storage system needs it
In this article
In brief
- Full autonomy when the sun is gone: After several days of rain or snow, your battery storage is left empty. A SPARK generator with 2-Wire automatic start switches on by itself when the battery drops to a critical level (e.g. 20%) and quickly recharges it to 80%.
- Why is inverter technology essential? Cheap conventional generators have high voltage distortion (THD), so advanced solar inverters reject them. SPARK inverter models deliver a clean sine-wave voltage that the inverter accepts without any problems.
- The 30–50% load rule: Never size a generator to run at 100% of its capacity. You get the most efficient, longest-lasting operation when the generator runs at just a third to a half of its maximum power.
A solar PV system with battery storage is a great step towards energy independence. In practice, however, its natural limitation soon becomes clear: the sun doesn’t always shine. Several days of rain, autumn fog or snow on the solar panels in winter mean your battery storage runs flat – and despite your costly solar investment, your house is left in the dark during a power cut.
This is where a backup generator comes in. But be careful – an ordinary pull-start generator or a cheap construction-site generator will not work with a solar PV system. You need a system with 2-Wire automatic remote start and stable inverter voltage.
How does SPARK 2-Wire remote start work?
The 2-Wire system (two-wire start) is the industry standard for communication between a solar inverter (e.g. Victron, Deye, Huawei, Sungrow) and a generator. When the inverter detects that battery capacity has dropped to the set critical threshold (e.g. 20%), it sends a simple signal (a contact closure) to the SPARK generator over two wires.
The SPARK generator’s built-in automatic control detects this signal, runs the start sequence by itself (choke on, starter motor engaged) and begins generating electricity. Once the inverter has charged the battery to the desired level (e.g. 80%), it cuts the signal and the generator automatically shuts down safely and cools down.
The cheap generator trap: why does the inverter reject the power supply?
In our shop and service centre, we often meet customers who first bought an affordable, conventional construction-site generator. But when they connected it to their solar system, the inverter simply rejected the generator or reported an error.
Why does this happen? Conventional generators have high voltage waveform distortion (THD – Total Harmonic Distortion) and frequency fluctuations whenever the load changes. Modern smart inverters apply extremely sensitive safety criteria – if the incoming power is not perfectly “clean”, they will not accept it for charging the batteries at all, to avoid damaging the electronics.
All SPARK models marked iA (petrol inverter) and DiA (diesel inverter) produce a pure sine wave with minimal THD, ensuring 100% compatibility with every brand of solar inverter on the market.
The golden rule of sizing: why shouldn’t you run a generator at 100%?
The second most common mistake buyers make is choosing an undersized generator that then runs at the limits of its capacity (80–100% load). This drastically shortens the life of the engine and alternator.
We recommend choosing a generator sized so that it runs at 30% to 50% of its rated power while charging your battery storage. At this point the generator has the lowest fuel consumption per kWh produced, runs at lower engine speed and with less noise, and will serve you reliably for decades.
Overview and comparison of SPARK 2-Wire inverter generators
Depending on the size of your solar PV system and battery storage, you can choose between SPARK petrol and diesel inverter models, all of which support 2-Wire automatic start:
| SPARK model | Fuel type | Rated power (kW) | Recommended continuous load (30–50%) | Suitable for storage capacity |
|---|---|---|---|---|
| SPARK 6000iA / 8000iA | Petrol (inverter) | 5 – 6 kW | 2.0 – 3.5 kW | Smaller storage systems (5–10 kWh) |
| SPARK 13000iA / 15000iA | Petrol (inverter) | 9.5 – 12.0 kW | 4.5 – 6.0 kW | Mid-size storage systems (10–25 kWh) |
| SPARK 20000iA | Petrol (inverter) | 17.0 kW | 6.0 – 9.0 kW | Larger residential and commercial buildings |
| SPARK 8000DiA / 10000DiA | Diesel (inverter) | 6 – 9 kW | 3.0 – 4.5 kW | More demanding users / longer runtime |
Frequently asked questions
Can I connect a 2-Wire generator myself?
The mechanical and basic electrical connection is simple, but setting the parameters in the solar inverter (voltage thresholds, start time delays) and checking the earthing and phase sequence must be carried out by a qualified electrician or solar system installer.
What happens if the generator runs out of fuel during automatic operation?
Modern SPARK generators have built-in low-oil protection and shut down automatically if there is a fault in the fuel supply. However, we recommend checking the fuel level regularly or, for diesel models, fitting a larger external fuel tank to cover longer outages.
Is a petrol or a diesel inverter generator the better choice?
Petrol inverter models (e.g. SPARK 8000iA or 13000iA) are exceptionally quiet, run smoothly and are cheaper to buy. Diesel models (DiA), on the other hand, are an excellent choice for sites where you already store diesel fuel or where you plan very frequent, long-running operation.
Can I connect a conventional generator with AVR regulation to a solar PV system?
No, connecting a conventional AVR generator is not recommended. Despite AVR voltage regulation, such generators show excessive deviations in frequency and voltage waveform (high THD). The solar inverter will detect these disturbances as a poor-quality or unsafe grid and will simply not accept the generator as a source for charging the batteries.
Should I buy an open-frame generator or a model with a soundproof canopy?
For generators that will be permanently on standby outdoors and operate in all weather conditions, we strongly recommend a model with a soundproof canopy. The canopy reduces operating noise by at least 5 decibels (which in practice means noticeably quieter operation), while keeping the generator’s vital parts, automatic controls and battery well protected from rain, snow, moisture and tampering by unauthorised persons.
Not sure which SPARK generator is right for your battery storage?
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