EV Charger SIM Card Connectivity: How Spitfire Keeps ZOLB’s Network Online

At ZOLB EV, every charger we install is smart, connected and managed in real time. From destination chargers at hotels and retail parks to workplace and fleet charging stations, our EV charging networks depend on one quiet hero inside every unit: the EV charger SIM card.

Those SIMs are what keep chargers talking to our software platform and our drivers’ apps, authorising payments, starting and stopping sessions, pushing live status updates and feeding performance data back to our team. To make that work across busy city centres and remote rural sites, we needed a connectivity partner that could match our ambitions.

That’s where Spitfire comes in. Spitfire’s IoT SIMs and One Network architecture now underpin seamless connectivity across our estate, helping us deliver reliable, secure EV charging and secure data transmission for businesses and drivers all over the UK.

What Is an EV Charger SIM Card?

In simple terms, an EV charger SIM card is a specialised IoT data SIM that sits inside a charger and connects it to the cloud over the mobile network, enabling us to connect EV chargers reliably across all types of sites.

Instead of relying on fixed lines or on-site Wi-Fi, which can be expensive, complex, or simply unavailable, each charger uses its SIM to:

• Communicate with our back-office software
• Talk to the ZOLB EV driver app for starting/stopping sessions
• Send live pricing, usage information and insights into energy consumption
• Report status, alerts and error logs to our support team

For us as a Charge Point Operator (CPO), that SIM isn’t a “nice to have” add-on. It’s essential infrastructure. If the SIM isn’t rock-solid, driver experience, uptime, and revenue are all at risk.

The Connectivity Challenge Behind Smart Destination Charging

ZOLB EV focuses on making charging easy in the places people actually spend time, supporting smart charging across hotels, attractions, workplaces and retail destinations and community spaces.

That means our chargers end up in all sorts of environments:

• Underground or multi-storey car parks
• Rural venues with patchy coverage
• Older buildings where running ethernet to a data room is complex or disruptive

In many of these locations, pulling new cables isn’t practical or cost-effective, especially when expanding EV charging infrastructure across diverse sites. We needed an EV charger SIM card solution that:

• Works out of the box, with minimal on-site configuration
• Delivers strong coverage nationwide, including trickier spots
• Integrates cleanly with our existing hardware and software
• Scales from a handful of chargers to hundreds, without re-architecting everything

Spitfire’s IoT SIMs and private One Network architecture were a strong fit from day one.

Why We Chose Spitfire for Our EV Charger SIM Cards

When we started looking for an IoT connectivity partner, we spoke to multiple providers. As a fast-growing business, we needed someone who could see beyond our initial SIM volumes and work with us on a long-term roadmap.

Spitfire stood out for a few key reasons:

1. A Partner That Backed Us Early

Many providers focus purely on large, established estates. Spitfire were willing to engage from our early stages, understanding that our charger rollout was accelerating quickly and that we needed a partner who could scale with us.

That flexibility has been crucial: as we’ve deployed more destinations and expanded into new sectors, our EV charger SIM card estate has grown alongside us, without needing to change platform or pricing model.

2. Flexible, EV-Friendly Pricing Models

Charging data usage varies: a hotel car park with steady daily usage looks very different to a seasonal tourist attraction or a newly launched site ramping up adoption.

Spitfire’s IoT pricing models give us options, including:

• Pay-per-MB (pay for what we actually use)
• Fixed data bundles per SIM
• Pooled data shared across multiple SIMs

That lets us align connectivity costs with real-world charger behaviour and avoid overspending on unused data.

3. A Network Designed for IoT – Not Just “Another SIM”

Spitfire isn’t just reselling someone else’s mobile network. As a full MVNO, they run their own core network, which means more control over how services are designed, delivered and supported.

For us, that translates into:

Confidence that the IoT SIM service is being actively engineered, not just white-labelled

Faster, more informed technical support

The ability to fine-tune connectivity options to fit our use case

What Spitfire’s IoT SIMs Deliver for Our Chargers

Rock-Solid Coverage Across the UK

Our chargers are installed in locations all over the country, so mobile coverage is non-negotiable. Spitfire’s offering includes single-network and dual-IMSI multi-network SIMs designed to maximise availability by using the best available radio access network at each site.

In practice, that means:

• Reliable connectivity in both urban and remote areas to support accurate station availability reporting
• Fewer site-specific workarounds (e.g. extra repeaters or external antennas)
• Less time troubleshooting connectivity, more time deploying new charge points

For many sites, a single-network EV charger SIM card is enough. Where we know coverage is more challenging, we have the option to step up to multi-network SIMs for added resilience.

Security Built In, Not Bolted On

EV chargers are part of the UK’s critical infrastructure. Protecting them and the data they handle is essential, making enhanced security a core requirement of our connectivity.

Spitfire’s One Network keeps devices off the public internet by using a private MPLS-based architecture. Chargers are given private IP addresses and are not directly visible to internet-based scanners or attackers.

For ZOLB and our customers, that means:

• Reduced exposure to common IoT attacks
• Simpler security architecture, no sprawling web of VPNs to maintain
• Peace of mind that connectivity has been designed with security in mind from the ground up

Flexible Plans as Our Network Grows

Not all chargers behave the same, and their connectivity doesn’t need to either.

With Spitfire, we can mix and match:

• Pay-per-MB for low-traffic or early-stage sites
• Fixed bundles for established, predictable locations
• Pooled data where usage varies across a group of SIMs

This flexibility means our EV charger SIM card strategy can evolve with our rollout, rather than locking us into one rigid model.

Visibility and Control Through a Single Portal

Managing SIMs across dozens of sites can quickly become complicated. Spitfire’s portal gives us a central place to see:

• Active SIMs and connection status
• Data usage trends
• Alerts that might indicate unusual activity or misconfiguration

Combined with our own back-office tools and the ZOLB EV app, it gives us end-to-end visibility, from driver session to SIM-level connectivity.

The Real-World Impact on ZOLB’s Charging Network

Behind every smooth charging session, there’s a chain of technology working quietly in the background. Thanks in part to Spitfire’s IoT SIMs, that chain is stronger and simpler:

• Drivers get a seamless experience
  Start and stop sessions through the ZOLB EV app, see real-time pricing and progress, and receive clear notifications when charging is complete.
• Site hosts get reliable infrastructure
  Retailers, hotels, workplaces and other venues can trust that their chargers are online and ready when drivers arrive, helping them generate revenue, attract customers and support sustainability goals.
• Our team gets live, actionable data
  We can spot issues early, schedule maintenance more effectively, and optimise performance across our estate, instead of reacting only when something breaks.

In other words, when the EV charger SIM card works, everything else gets easier, for us, for our partners, and for drivers.

Building the Future of EV Charging, Together

ZOLB EV exists to make EV charging seamless, accessible and reliable for businesses and drivers across the UK. Spitfire’s managed IoT connectivity plays a key role in that mission, giving us the confidence to roll out smart chargers wherever they’re needed, without compromising on uptime, security or control.

As our network grows, our partnership with Spitfire means we can keep scaling without reinventing our connectivity each time, supported by extended coverage across every new site. The hardware, software and EV charger SIM card strategy all move forward together.

If you’re a business looking to add EV charging to your site, or upgrade an existing setup, we’ll take care of everything from charger selection and installation to smart software and dependable connectivity. Ready to bring reliable EV charging to your location?
Get in touch with the ZOLB EV team and let’s design a solution that works for your customers, your site, and your future.