Charging with Solar PV: Turning Sunlight into Smarter EV Charging

Solar power offers one of the simplest ways to reduce the running cost of an electric vehicle. When paired with intelligent control, the energy your panels generate during the day can be captured and stored directly in your EV, instead of being exported to the grid for little financial return. With NexBlue’s Solar Surplus Charging, this process becomes automatic, predictable and highly efficient for both homes and commercial sites.

Why Solar Surplus Matters

Most properties see lower power usage during the day. Homes may be empty, offices may be between shifts, and commercial sites often have quieter periods. At the same time, solar panels are generating their highest output.

Without smart control, much of that valuable energy is simply exported. Export tariffs are often far lower than the price you pay for grid electricity, which means missed savings. By making your EV the preferred destination for your solar energy, you keep more of that value on site.

How Solar Surplus Charging Works

The NexBlue Zen monitors energy flow at the property boundary using CT clamps on the incoming supply. From this, it identifies when power is being exported. Export means only one thing: you are generating more electricity than the site is using.

Whenever export is detected, the NexBlue charger adjusts its charging rate to match the available surplus. If a cloud passes or an appliance turns on inside the building, the charger automatically reduces its speed. When the surplus increases again, charging ramps back up. You always stay within the limits of what your solar system can provide.

This makes the system predictable, safe and efficient. You only charge with genuine surplus, not with grid electricity unless you choose to.

Why NexBlue Measures Export, Not Generation

Some systems look only at how much the solar panels are producing. In reality, that doesn’t tell the whole story. A kettle, heat pump or piece of commercial equipment turning on can instantly consume that generation. If the charger continues at a fixed rate, it may begin drawing power from the grid.

By monitoring export instead of just generation, NexBlue always responds to the true net position of the property. If power is leaving the site, the system increases charging. If not, it scales back. This approach ensures you make the most of your own solar energy without accidental grid import.

The NexBlue Zen (Current Sensor) does have the ability to measure the Solar generation however. This is not utilised in a functional capacity, but can be helpful for customers or site managers to understand how much power their solar systems are generating on a given day.

Charging on Three Phase with Low Solar Output

There is a well known limitation in EV charging. On any phase, the charging current cannot drop below 6 amps. Below this value, the vehicle will simply not accept charge. For three phase chargers, this limit applies to each phase individually.

This creates a challenge. A site may have solar surplus, but spread thinly across three phases. For example, there might be 5 amps of surplus on each phase. That is 15 amps in total, yet the charger cannot start, because each individual phase is under the 6 amp minimum.

NexBlue’s 3-to-1 Phase Switching

This is where NexBlue’s 2025 range introduces an important innovation. The system can detect when surplus energy exists across all three phases and combine it into a single usable supply. Instead of treating the surplus on each phase separately, it gathers the available power and delivers it as a single phase output.

Using the earlier example, three phases each with 5 amps of surplus become one phase with 15 amps. This is enough to begin charging at the required minimum of 6 amps. As the solar output changes, the system continuously adapts, ensuring that as long as surplus exists, it can be used.

A Simple Analogy

Imagine three small streams flowing into separate channels. None has enough force on its own to turn a waterwheel. If you merge those streams into one pipe, the flow becomes strong enough to drive the wheel. NexBlue’s 3 to 1 phase switching does the same for solar energy, combining scattered power into something usable.

What This Means for Homes and Businesses

Solar surplus charging brings several important benefits:

• Lower energy bills by prioritising free solar power

• Less exported energy and better use of every generated kilowatt

• Smoother and more predictable charging that adapts in real time

• Earlier start and later continuation of solar charging, even during weak sunlight

• Better performance on three phase sites with fluctuating generation

For both domestic and commercial settings, this creates a more efficient and cost effective energy ecosystem, where the EV becomes a natural extension of the building’s renewable generation.

Bringing Solar and Smart Charging Together

Solar power is at its best when used on site. NexBlue’s approach ensures that every part of the system works in harmony, from moment to moment, making solar EV charging simple and reliable. With export based control, adaptable charging rates and advanced 3 to 1 phase switching, you get maximum value from your panels without additional effort.

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