Charger Firmware, Built to Spec by a Team That Ships Hardware
EV charger firmware is the embedded software inside an EVSE that runs the charging state machine, safety interlocks, metering, connectivity and the OCPP client.
Who this is for
Charger OEMs building a new product from the board up. Manufacturers stuck with an unreliable firmware vendor whose OCPP client keeps dropping the CMS. Hardware companies needing OCPP certification and IEC 61851 type approval, on a real schedule, with support during findings.
What we build to spec
The whole firmware stack, or the modules you don't have:
- IEC 61851 control pilot state machine (states A-F, CP PWM, PP handling, RCD and relay control)
- OCPP 1.6J or 2.0.1 client over WebSocket with TLS, offline queueing and reconnect
- Metering integration: MODBUS, pulse, internal ADC with class-1 or MID accuracy
- BLE GATT services for user management, config and offline authorization
- Secure OTA with ping-pong (dual partition) storage, signed images, automatic rollback
- Session journaling in NVS to survive power loss mid-transaction
- Multi-connector and three-phase support with per-phase current control
- Diagnostics, event logging and remote debugging hooks
Platforms
ARM Cortex-M microcontrollers for most AC chargers, whether cost-optimised single-core parts or higher-throughput Cortex-M7 for safety-partitioned designs. Xtensa and RISC-V families for connected AC hardware that needs WiFi and BLE on-chip. Linux-based controllers for DC fast chargers with CAN buses to the power modules. Android for touchscreen consoles and public dispenser front-ends. Bare-metal and RTOS builds both supported. If the board is custom, we work from your schematics; if hardware is part of the engagement, we work from ours.
Safety and compliance
IEC 61851-1 type test support with accredited labs. EMC-aware firmware design (avoiding switching patterns that fail radiated emissions). ISO 15118-2 and 15118-20 readiness on AC hardware. UL 2594 and UL 2231 firmware requirements for US markets. CE marking support. We stay engaged through certification, fixing findings as they emerge instead of handing off after delivery.
Security
Secure by default across four layers: encrypted communication to the CMS, authenticated access to every local interface, cryptographically signed firmware verified before boot, and hardware-backed device identity where the silicon supports it. Every project ships with a documented threat model, so the security assumptions are visible on paper, not implied.
Why RIOD
We design charger PCBs and enclosures. Firmware develops against the real power electronics that ship in the product: meter values matched to the CT class, relay control tuned to the contactor's coil characteristics, RCD detection validated against the actual sensor. Our own PowerPod chargers run this stack in the field, so what we ship to you has already been through real deployments.
Engineering notes behind EV Charger Firmware Development.
Questions we get most.
What does EV charger firmware development include?
The charging state machine per IEC 61851, safety interlocks, metering, the OCPP client, connectivity (WiFi, Ethernet, 4G, BLE), OTA update capability and local user management. RIOD delivers this as a tested stack on your hardware.
Which platforms do you develop charger firmware for?
ARM Cortex-M for most AC chargers, Xtensa or RISC-V where WiFi and BLE need to live on the same die, higher-end ARM or Linux-based controllers for DC fast chargers, and Android for touchscreen consoles. Bare-metal and RTOS builds both supported. If your board is custom, we work from your schematics; we also design charger hardware ourselves.
How do secure OTA updates work on an EV charger?
We implement dual-partition (ping-pong) firmware storage: the new image downloads to the inactive partition, is signature-verified, then booted. If it fails health checks the charger rolls back automatically. Updates are managed fleet-wide via OCPP or our operations suite.
Can the charger work without internet?
Yes. We implement offline authorization lists, BLE-based user control and store-and-forward transaction journaling, so the charger operates fully offline and syncs when connectivity returns. See our offline charging solution.
Do you help with OCPP certification and IEC compliance testing?
Yes. We develop against OCTT test cases for OCPP compliance and support IEC 61851 type testing with accredited labs, including fixing findings during certification.
Ship a charger that boots the first time.
Tell us about your hardware. Let's get on a call.
Discuss your firmware spec