EV charger connectivity is unusual in the IoT world because the consequences of getting it wrong are visible to the end user immediately — a charger that cannot authorise a charge session is a charger that cannot be used. The signal testing requirements for EV charger installations are therefore more demanding than for many other IoT applications, and the cost of discovering a connectivity problem after groundworks and installation are complete is significant.
EV charger connectivity requirements
| Requirement | OCPP specification | Signal threshold |
|---|---|---|
| Uptime | Continuous connection required | RSRP better than -100 dBm on primary operator |
| Latency | OCPP 1.6: tolerant. OCPP 2.0: <2 seconds preferred | SINR above +6 dB |
| Bandwidth | Low (<100 kbit/s for OCPP messaging) | Any functional LTE connection sufficient |
| Failover | Not in spec, but recommended for reliability | Secondary operator configured; tested independently |
Why pre-install signal testing is essential for EV
EV charger posts are typically set in concrete or mounted on structures. Repositioning after installation is expensive. The charger itself is often installed by an electrical contractor who does not specialise in cellular connectivity — CellTester gives any installer a professional commissioning capability without cellular expertise.
Battery-powered testing is particularly valuable for EV sites: groundworks are often not complete when the charger position needs to be confirmed. A Teltonika router on a BAT120, positioned at the proposed charger location height with an external antenna, gives you the real signal picture before a single post hole is dug.
Operator selection for EV charger sites
EV charger deployments across the UK include rural service stations, car parks, retail sites and residential developments. Operator coverage varies significantly between these environments. CellTester’s automated multi-operator sweep tests EE, Vodafone, Three and O2 in sequence and identifies the most reliable primary and failover operator for that specific location — before SIM provisioning is locked in across a rollout.