April 25, 2024
Ed Harvey

EECA’s smart charger approved list explained — and why it won’t achieve EECA’s stated objectives

EECA’s smart charger approved list explained — and why it won’t achieve EECA’s stated objectives


  • EECA has published an “EV Smart Charger Approved List” based on a set of technical criteria.
  • We believe that EECA has largely ignored industry feedback regarding the technical criteria; and has failed to justify how conformance with the criteria will impact energy efficiency or consumer outcomes in practice.  
  • If you’re concerned about purchasing an EV charger that’s not on EECA’s list, we suggest reading further to ensure you make an informed decision.

In March 2024, the Energy Efficiency and Conservation Authority (EECA) of New Zealand published an “EV Smart Charger Approved List” aimed at assisting New Zealanders to “identify, and purchase, smart and efficient EV chargers” with a stated goal of benefiting both the user and the national electricity grid.  

By now you might have guessed it, Evnex’s products aren’t included on the list. Now we’re a pretty resilient bunch here at Evnex, but we’re really disappointed that imported products are being recommended over our locally manufactured products without what we believe to be a good technical justification.

At Evnex, we believe the motivation behind producing the list is sound; both consumers and the environment stand to benefit to the tune of billions of dollars and significant carbon reductions if smart charging is implemented effectively in the coming years, and we’re working super hard to get there! Where we disagree with EECA is whether the technical performance criteria for the list will achieve their stated objectives.  

Why is smart charging required for a fully electrified future?

Electric vehicles place considerable demand on the grid when compared with other household appliances. A modern EV can draw 32 amps on a single-phase connection, roughly half of a typical home’s capacity. Currently, electric vehicle penetration is low, and some households have two vehicles, relying on the EV for shorter trips.  

Over time, EV penetration will increase and believe it or not, tradie’s utes and the Remuera tractor will become electrified, resulting in many houses having a sustained 32-amp EV charging load, typically starting in the early evening when the grid is already at peak demand. Without coordinated EV charging, many electricity networks are likely to require costly investment in the coming years to withstand this increased loading, and that will hit all New Zealanders in the pocket.

Additionally, as the energy sector moves towards a fully renewable grid, coordinated EV charging can help reduce carbon emissions by aligning charging with times when renewable generation is abundant, such as during periods of wind and solar energy production.

EECA’s technical criteria explained

Electric vehicle supply equipment (EVSE) can be included on EECA’s list if it meets a set of technical criteria, available here. For brevity, let’s focus on the criteria that we believe are not constructive in achieving EECA’s stated objectives – connectivity criteria and randomised start function criteria.  

Connectivity criteria – EECA requires that hardware must comply with Open Charge Point Protocol (OCPP), and this must be configurable by the user. OCPP, though unfamiliar to your average consumer, defines how a charge point ‘talks’ with the cloud. However, as it was initially developed for public charging stations, it’s not particularly suited for configuration by consumers. In fact, Evnex chargers use OCPP, but where we fall short of EECA’s expectations, is that we don’t allow for our chargers’ OCPP connections to be pointed to a different software platform. There are a few reasons why:  

  • Reduced capability: OCPP lacks standardisation for supporting many of the additional capabilities that Evnex has developed, such as configuration of solar diversion, home overload protection and load balancing. By necessity, Evnex has developed proprietary messages within OCPP to support these features and therefore they are not supported if a user was to connect the hardware to a generic OCPP software platform.

  • User experience: Open, fully interoperable systems can have benefits, but they introduce a significant increase in variables, often leading to poorer user experience. There are hundreds of OCPP cloud platforms that Evnex chargers could be connected to, many of which interpret the protocol in conflicting ways. Love them or hate them, Apple is a great example of a company that delivers seamless user experience which users now take for granted, by owning the hardware and software ecosystems.  

  • Technical support: Breaking the cloud connection makes support difficult. Evnex is known for providing outstanding technical support — many of our customers will recall speaking with our amazing Pedro Cassini or Jason Zhang. What helps us to provide quality support is that we can diagnose the hardware directly via our software platform. The problem with breaking the manufacturer’s link to the product is that for many issues it becomes opaque as to whether the fault lies with the hardware or cloud platform to which it is connected. This often leads to customers getting stuck in the middle as the messenger when neither party claims responsibility.

  • Practical limitations: While EECA’s ‘interoperable’ philosophy may sound appealing, it has not addressed the inherent practical challenge of how the average consumer will configure the OCPP connection; and whether the vast majority of drivers will be engaged enough to do so — not everyone is an energy or home automation boffin! EECA appears to have taken the approach of picking a protocol while leaving the practical implementation as ‘something to figure out in the future’. We think it’s short-sighted for EECA to recommend certain products without providing justification for how they expect these devices to improve energy outcomes. Evnex’s philosophy is that smart capabilities of hardware should be ready to go out of the box, without requiring complex setup by the customer.

  • Cybersecurity: EECA’s guidelines fail to address any consideration related to cybersecurity. We quote the referenced test procedure commissioned by Canterbury University, “This guideline does not attempt to cover all aspects of OCPP compliance, and entirely bypasses the security aspects of OCPP.” We believe that it is irresponsible for EECA to prescribe a protocol to the general public without any effort to address the inherent security risks associated with an open and interoperable system.

It is worth stating that Evnex understands that some EV drivers may desire an open OCPP compatible charger. They may wish to connect the charger to a bespoke home automation system, or may be a customer of an electricity retailer that provides an OCPP connection for a selection of tested and compatible chargers. However, these use cases currently represent a small minority of consumers.

We also recognise that some consumers may be concerned about hardware obsolescence if a manufacturer was to fail or discontinue support for a particular product. Since we do use OCPP under the hood, it’s highly likely that we would release a final firmware update to unlock the connection in the unlikely event that Evnex was to cease trading.

Randomised start function criteria: EECA requires that “residential hardware must be configured to operate a default randomised delay of up to 600 seconds (10 minutes) at each charging instance.” The guideline does not make it clear as to why this functionality is required, but presumably the intention is to reduce a step change in EV charging load following a network blackout or brownout; or following a scheduled start which may coincide with a multitude of other chargers. This is often driven by time-of-use electricity tariffs, for example, Contact Energy’s plans which provide discounted energy between 9pm–12am (see figure 1 below).

A randomised delay implemented by charge point manufacturers makes sense to protect the network in the first instance, when a charge point is recovering from a power outage. It does not make sense when implemented at “each charging instance” as is required by the criteria. This does not align with consumer interests for the following reasons:

  • For drivers who have purchased a smart charger to automatically charge within a ‘free charging window’, a delayed start by up to 10 minutes dilutes the value of their investment as it reduces the amount of energy that the charger can deliver within that window.

  • For those who employ solar diversion features, this requirement results in poor utilisation, as every time the sun comes out, the charger will be required to delay its start time for up to 10 minutes.

  • Evnex’s view is that requiring hardware manufacturers to implement controls to address perverse outcomes caused by energy retailer’s time-of-use tariffs is counterproductive. Evnex is already working with multiple retailers to develop flexible tariffs which will automatically distribute charging times. Enforcing randomised start times on every session is a crude solution that is likely to erode driver confidence and acceptance of smart charging.

Above shows the mean power output per charger, across Evnex's entire residential fleet. It shows that time of use tariffs do cause considerable peaking of demand when costs reduce. Is it right however to address this in hardware, when the cause is clearly the tariffs?

Why the list matters

While EECA’s EV Smart Charger Approved List is only a guideline, we believe it matters, as certain products are being excluded based on a misguided view of what’s right for the consumer. Furthermore, EECA’s technical criteria may be used as precedent for future legislation or financial incentives for certain ‘smart’ products.

EECA’s position on OCPP and interoperability appears to be based on advocating for consumer choice. We believe however that the technical criteria limit the ability of charging companies to move fast and innovate outside of the bounds that EECA specify. Long term, this won’t be good for the consumer.  

We also think that EECA’s concerns about software lock-in are spurious, when it is very common for products like solar inverters, smartphones, heat pumps, alarm systems, and security cameras to be sold with a closed software ecosystem. From an energy efficiency perspective, Evnex has demonstrated significant commitment to innovation and demand flexibility. We have provided technology for New Zealand’s largest smart-charging trials, and the only live grid carbon reporting feature to help drivers choose the cleanest time to charge. Evnex is also an active member of FlexForum – an industry group established to accelerate the development of standards and market reform in support of a thriving flexibility market.

Our recommendation to EECA


  • EECA should remove the requirement for chargers to have ‘open’ OCPP access, and ideally remove any reference to OCPP, as EECA should not be ‘picking winners’ without having a broader understanding of technologies that could, in theory, deliver an equivalent or superior outcome for flexibility and energy efficiency including protocols like OpenADR and IEEE2030.5.  

  • EECA should remove the requirement for chargers to include a randomised start time for every session and instead, if they deem appropriate, focus their efforts on addressing the issue at its source: time of use tariffs that are causing these perverse behaviours. Evnex’s network data has shown that time of use tariffs significantly influence consumer behaviour resulting in localised peaks.

  • As the list evolves, we think that EECA should consider including home overload protection in their requirements as it provides a clear benefit to the consumer and electricity distributor by avoiding outages, blown pole fuses and potential safety issues.

In summary, our stance is that EECA’s guidelines should focus on the basics of ensuring chargers have two-way communication and can vary their charging speed. It's too early to say how the smart grid will evolve, so disadvantaging certain manufacturers for not conforming to a restrictive protocol is likely to stifle innovative solutions.

In the event that EECA doesn’t change its position, you can be assured that we’ll continue to work hard as New Zealand’s largest EV charging team, to help our drivers save money and reduce their carbon emissions.

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Ed Harvey
Ed Harvey
April 25, 2024