November 2, 2021
Justin Rypma

Solar EV Charging

Solar EV Charging

Electric Vehicle Charging With Solar Panels

EV solar charging

While it’s true that investing in electric vehicles (EVs) or home solar can reduce your reliance on fossil fuels, it's also important to ensure that you're utilising your solar generation efficiently to reduce your overall carbon footprint. If your EV is charging from non-renewable grid power, or your solar energy is going unused at high generation times, they can greatly waste the potential benefits of an optimised solar EV charging system.

Today we’ll cover how to charge your EV with solar power, and why a smart charging feature called solar export diversion is key to forming a healthy relationship between your EV charger and home solar system. 

What is solar export diversion? 

In a nutshell, it’s an automated charging feature built to maximise the benefits of locally generated solar energy, prioritise EV charging from clean energy, and minimise the electricity costs of grid power to charge your vehicle.

Evnex's solar EV chargers implement this tool by regularly measuring the amount of power that your home is using or generating at any given time. If your home starts exporting power to the grid above a certain threshold, it will divert the power to start your charging session automatically. It then dynamically varies the charging speed to match the solar energy you would otherwise be exporting. 

Ultimately, this means that you'll 'self consume' more energy as opposed to selling it back to the grid at a lower price than you would buy it for. It also means that you’ll be charging your EV from 100% renewable energy. 


Key Advantages
  • Ensures clean charging of your EV
  • Allows for greater control of your solar energy
  • Reduces energy costs to charge your EV

Solar charging in action

Now that we understand the advantages of solar EV charging, let’s look at the automated steps taken to start a solar charging session.

A diagram of an EV solar charging process part 1
(Solar energy and grid energy being used by a home)

Sometimes your home solar system will generate little to no power and require additional energy from the grid to meet your demands. In this case, your solar charger will detect the imported power and won’t start an EV charging session unless you override it.

A diagram of an EV solar charging process part 2
(Solar energy being exported to the grid)

If your home energy demands are less than the power being generated from rooftop solar panels, the power will be exported back to the grid. Detecting this, your solar charger will monitor the export amount until it meets a minimum 1.5kW of power for 60 seconds before starting your solar charging session. This ensures you can sustain a minimum charging speed for your EV (1.4kW). The more excess solar that's available, the quicker the charging time. 

A diagram of an EV solar charging process part 3
(Solar energy being diverted to charge an EV instead of being exported to the grid)

If your solar availability decreases below 1.5kW for 60 seconds (due to an increase in home energy consumption, time of day, or weather) your smart solar charger will pause the session and revert to monitoring for a rise in solar power levels.  


Maximising your renewable energy usage

In the case of solar power, the peak demands of residential power usage aren’t always aligned to times when solar energy is most available.

During times of low use, your excess solar can either be stored in battery systems, or be exported back to the grid. While high capacity battery storage continues to drop in price, a Tesla Powerwall is currently $14,000 (NZD) before installation, these systems may be too expensive for homeowners to justify when considering installing a solar panel system.

An intelligent solar EV charger is one solution to this puzzle. Although not a perfect home battery alternative, it does allow for free energy to be diverted and stored in your electric car’s battery instead of being exported to the grid. 

*It's important to note here that solar export diversion is a one-way energy flow and not the same as V2H (Vehicle to Home) technology. 

An Evnex solar EV charger


Is solar EV charging for you? 

While energy retailers may promote off-peak times as cleaner available energy, you still may be charging your EV from power sources that produce dirty emissions. An easy way to guarantee your EV is charged with 100% green power is by harnessing your own home solar system. 


Are Evnex EV chargers compatible with my home solar system?

Evnex EV chargers include smart charging capabilities like solar export diversion as standard with every home install. The system relies on a power sensor placed at a building’s distribution board, not integrated into the solar inverter itself. So regardless if you have home solar installed yet, our EV charger will be ready to activate this feature in the future.


Using a solar EV charger

Evnex chargers are cloud-connected, allowing you to control and view charging history on your mobile device. You can schedule charge times or start and stop charging as needed. This way you can override solar charging to prioritise a faster charging time.


Thanks for reading and helping power the transition to sustainable electric mobility in New Zealand.

Did you find this article helpful? Or have topic ideas you’d like us to cover? Send an email and let us know at


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Justin Rypma
Justin Rypma
Marketing Content Lead
November 2, 2021