Car fleet being charged

Cellular, Wi-Fi and smart EV charging decisions

Electric vehicle (EV) chargers are no longer the passive devices they used to be. With the rise of smart EV chargers, intelligent networked charging becomes possible, ensuring load management, making billing easier and smoothing maintenance cycles. However, it’s not just an opportunity for EV charging businesses. As EVs continue to represent a larger portion of corporate vehicle fleets, fleet managers will need to assess their options as EV charger installations begin to roll out across UK business premises.

There are three communication options to consider when you’re looking to connect EV chargers to your charging management backend. These are cellular, Wi-Fi and Ethernet / LAN. Ethernet provides highly stable and secure data communications, yet the cost and complexity of running, tracing and fire-proofing cables limit its feasibility.

That leaves you with a choice of cellular or Wi-Fi. Let’s take a look at how these two options stack up against each other.

Communication reliability

Uninterrupted data communication is key to any smart charging installation. Real-time transmission of user commands and authorization data is a must-have to initiate charging sessions. Likewise, accurate and up-to-date information on charger availability enables value-add digital services like queuing prediction and smart navigation. Plus, intelligent management of charging schedules can reduce energy costs and relieve any undue pressure on the national grid.

Wi-Fi is readily available on almost every commercial premises. However, depending on the WLAN infrastructure, you may have little control over the connection quality. In addition to unexpected network outages, Wi-Fi is prone to interference issues as multiple devices compete for bandwidth. Wi-Fi’s short range also poses coverage problems and means you may need to install repeaters.

Conversely, cellular networks using the licensed spectrum are available everywhere, and they are highly reliable. While mobile coverage in indoor and underground garages, or on remote roadways, may be a challenge, IoT-focused cellular solutions circumvent the issue. Multi-network SIM cards, multiple redundant data routes and newer cellular technologies like LTE-M and NB-IoT mean better range and coverage at difficult locations.

Fleet ChargingEnhanced security

Security is a consideration that can get overlooked when installing EV charging capabilities on business premises. It’s not only extensive networks of public chargers that are at risk of attack. Even small scale private and home charging deployments could be exploited for electricity theft, Denial-of-Service attacks, network infiltration for ransomware and national power grid disruption.

Connecting your EV chargers to your Wi-Fi networks opens up two-way security risks. An EV charger can be used as a backdoor to infiltrate your workplace network to steal Wi-Fi credentials and access private and sensitive information. Your chargers could also be a hacker’s primary target with the intention of manipulating the maximum charging current to destabilise the local electrical system. When enough chargers are affected, the national grid could be compromised.

Security threats within public Wi-Fi networks are nothing new. But even with private Wi-Fi, proper measures to protect the local network and its connected devices are often neglected. Using default Wi-Fi passwords, failing to update device firmware and software, or leaving recent bugs unattended are just a few examples.

When you choose cellular connectivity, all these problems go away. Fleet managers can ensure the EV charging network is separate from the local Internet infrastructure, eliminating unnecessary attack points. Versatile cellular IoT solutions further provide a virtual private network where all data is encrypted and two-way communications with EV chargers are highly secured.

The benefits of remote access

When operating from multiple sites, being able to access and log into remote chargers makes troubleshooting a lot faster and more cost-effective. Instead of having to travel to the site, your team or supplier can collect charger logs for diagnostics from afar. Charger reboots can also be carried out and settings can be adjusted, saving time, reducing costs and minimising maintenance team involvement.

When using Wi-Fi-connected charge points, creating remote sessions requires the local network’s public IP address to be static or dynamically traceable. This comes with multiple problems. It involves a reconfiguration of the Wi-Fi router and firewall rules as well as access to administrator passwords, which demands network engineer and user consent. It also makes your routers visible to external traffic, exposing networks to more security vulnerabilities.

But there is a solution. When you equip your chargers with IoT SIM cards that use static private IP addresses these issues are no longer a concern. Fixed private IP addresses simplify remote access as they remove the need to install extra applications like dynamic DNS and port forwarding to trace the constantly changing IP. Additionally, a virtual private network enhances security by ensuring your chargers are not reachable from external points.

Your EV charging stations as an income generator

The future of EV means you may want to open up a portion of your EV charging stations to public use or for use by your site visitors. EV roaming allows drivers to use chargers managed by multiple charge point owners and operators, even if they are only a customer of one e-mobility service provider. Drivers can locate, book and access all charging stations within the roaming network from a single mobile app. Cellular modules often come with integrated GNSS and GPS capabilities or at least cell-level positioning, allowing potential users to locate your chargers the moment they go online.

Wi-Fi or cellular for your EV charging needs?

Wi-Fi is often considered as suitable for private and corporate EV charging, while cellular connectivity is considered more relevant for public chargers. However, this is not always the case. Wi-Fi holds an attraction, because connectivity costs can be avoided, but it also limits your control over reliability, while also exposing your business to more security risks and operational costs.

With the emergence of new cellular IoT providers, connectivity costs have decreased and will continue to do so. There are also more flexible data plans, specifically tailored to the consumption needs of EV chargers. When making your decision, it’s a balance between your business needs, technical requirements and security considerations.

Author: Frank Stoecker, CEO and co-founder at EMnify

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