Charger connectivity
A charger without a network connection is an expensive extension cord that can't take money. Connectivity is the least glamorous part of a site and the source of more "the charger is broken" complaints than anything with a power module in it.
What depends on the network
Almost everything a driver experiences as "the charger" is actually a conversation between the charger and a server somewhere else. When the connection is weak, the charger doesn't fail cleanly. It fails intermittently, which is worse, because it looks like a hardware problem and gets diagnosed like one.
- Authorization. Every app start, RFID tap, and Plug and Charge handshake asks the back office for permission. No connection, no answer, no session.
- Payments. The card terminal sends a pre-authorization to the processor before the session and a capture after it. A drop in between leaves you with a session you delivered and may not be able to bill.
- Uptime and monitoring. The software only knows what the charger tells it. An unreachable charger looks down even while it charges cars, and a charger that is online but failing every session can look fine. Weak connectivity makes your uptime numbers wrong in both directions.
- Remote fixes. Most faults can be cleared with a remote reset or a configuration change, if you can reach the charger. Every unreachable fault becomes a truck roll.
- Firmware updates. Updates are large, and large downloads over weak links fail. An interrupted update can leave a charger needing a site visit to recover.
- Pricing and configuration. Price changes, idle fees, and access rules only take effect when they arrive.
- Load management. Commands that cap site power to keep demand charges down are only as good as the link that carries them. If the command doesn't arrive, the peak does.
- Roaming. Sessions started from another network's app cross yet another connection before the charger ever hears about them.
What happens when a driver taps Start
From the benchmarks. In the small-town retail fleet, the two chargers with the worst uptime were both flagged for connectivity, not hardware. Same equipment as the rest of the fleet, weaker signal, worse results.
The options
| Option | Best for | Watch out for |
|---|---|---|
| Cellular, LTE Cat-1 or better | Most sites. No dependence on the host's network, fast to deploy. | Signal inside a metal cabinet, a single carrier, and network sunsets. |
| Cellular, LTE-M | Low-data devices. Workable for charger messaging. | Slow. Firmware updates take a long time and fail more often on weak signal. |
| Ethernet or fiber | The most reliable option when you can run it. | Trenching cost, and Ethernet's roughly 100 meter limit. Fiber or extenders beyond that. |
| Host Wi-Fi | Almost nothing. | Guest networks, password changes, captive portals, and an IT team that doesn't know your chargers exist. |
| Satellite broadband | Remote sites with no wired option and poor cellular. | Mounting, power, clear sky view, and business-use terms. Feed it through a site router. |
Buy for the network's future, not today's
US carriers shut down their 3G networks in 2022, and chargers with 3G modems went dark until the modems were replaced. Ask what cellular technology the modem uses, how long carriers are expected to support it, and whether the modem is a swappable part or a board replacement.
A modem in every cabinet, or one router for the site
A modem inside each charger means independent failures, but also a small antenna inside a metal box. One industrial router with an external antenna and two SIMs, feeding every charger over Ethernet, usually gets a much better signal. It is also a single point of failure, so buy one with dual modems or dual SIMs, and put it on the same maintenance plan as the chargers.
The payment terminal may have its own modem
Many payment terminals connect separately from the charger. That is two modems, two SIMs, and two ways to fail. A charger can be online while its terminal is not, and the driver will blame the charger either way. Check the terminal's signal too.
Pull a data conduit. When the trench is open for power, adding a conduit for Ethernet or fiber costs very little. Adding it later means another trench. It's the cheapest insurance on the site.
Why a tier 1 IoT provider matters
A SIM from a phone store is built for a person who moves around and tolerates the odd dropped call. A charger sits in one spot for ten years and needs to answer every time. The difference shows up at exactly the wrong moments.
What tier 1 means
- Direct relationships with the major carriers, or the carrier itself.
- Multi-carrier SIMs that switch automatically when the primary carrier degrades.
- Private network options (a private APN and static IPs), so your chargers aren't sharing the public internet path with everyone's phones.
- A management platform showing usage, connection status, and alerts for every SIM.
- Pooled data across your fleet, so one chatty charger doesn't hit an overage cliff.
- Industrial SIMs, often soldered to the board, rated for heat, cold, and vibration.
- Support that picks up and can see your SIMs when you call.
What goes wrong with the cheap option
- Deprioritization. Consumer and low-cost plans get pushed down the queue when a tower is busy, which at a gas station is exactly when drivers want to charge.
- SIMs deactivated for inactivity or unusual usage patterns, with nobody watching when it happens.
- Carrier network address translation that silently closes idle connections. Chargers then drop off, reconnect, and drop again, which looks like a flaky charger.
- No visibility. When a site goes quiet, you can't tell if it's the charger, the SIM, or the carrier.
Examples, not endorsements. Carriers: AT&T, T-Mobile, Verizon, all of which run IoT divisions. IoT connectivity providers: 1NCE, Hologram, KORE, Soracom. Industrial routers: Cradlepoint, Digi, Peplink, Sierra Wireless, Teltonika.
Questions for your IoT provider
- Which carriers does the SIM use, and does it fail over automatically?
- Listen forAt least two major carriers, with automatic switching based on signal and service.
- Do you offer a private APN and static IPs?
- Listen forYes, and a straight answer on how it helps keep chargers reachable.
- What happens when a SIM hits its data limit or goes quiet?
- Listen forPooled data, alerts before anything is cut off, and no silent deactivations.
- Is the modem certified on the carriers you use?
- Listen forCarrier certification for the exact modem in your charger. Uncertified modems can be refused by the network.
- What can I see, and what can you see, when a charger goes offline?
- Listen forPer-SIM connection history and signal readings, available to you directly.
When the network drops anyway
It will. Decide in advance what the site does, because the default is usually "whatever the firmware happened to do."
- Local authorization. Chargers can keep a list of known RFID cards and members so regulars can still start sessions offline.
- Store and forward. OCPP chargers can queue session records and send them when the link returns. Confirm yours does, and that your software accepts late messages without mangling the bill.
- Card payments. Most terminals need to reach the processor to authorize. Choose between refusing sessions and allowing limited free or deferred sessions, and know what each costs.
- Keep-alive settings. Heartbeat and connection keep-alive intervals need tuning for your network, or carrier equipment will quietly close idle connections.
- Monitor the link itself. Track reconnections per day and signal readings over time, not just online or offline. A charger reconnecting forty times a day is telling you something before it fails.
Check a real site. The connectivity check grades the signal where your charger will stand and tells you what setup it needs. Open the connectivity check.