⚡ Reduxi Controller · Knowledge Base
How to add an EV charger via OCPP 1.6J
General guide for connecting any OCPP 1.6J‑compatible wallbox to the Reduxi Controller, so that the Controller can monitor and control charging with PV surplus and load management.
📋 In this article
1 Technical documentation
OCPP (Open Charge Point Protocol) is an open, manufacturer‑independent protocol between an EV charger and a management system. In this setup the Reduxi Controller acts as the local OCPP server (central system) and the charger connects to it as a charge point – no cloud service is needed. Any charger that supports OCPP 1.6J (JSON over WebSocket) and allows a freely configurable server address can be connected this way.
Protocol
OCPP 1.6J
Connection
WebSocket ws:// (local)
Network
LAN / Wi‑Fi via router
Device identifier
Charge point ID
Smart charging
Charging profiles in A
Reduxi device type
EV charger · OCPP 1.6 - JSON
Manufacturer documents:
- OCPP manual of your charger – where OCPP is enabled, which fields exist (server URL, charge point ID, security profile) and which OCPP messages are supported
- Open Charge Alliance – OCPP 1.6 specification: openchargealliance.org
Required OCPP functions For monitoring and control, the charger must support the feature profiles Core and SmartCharging (BootNotification, Heartbeat, StatusNotification, MeterValues, Start/StopTransaction, SetChargingProfile). RemoteTrigger (TriggerMessage) and RemoteStart/Stop are recommended. OCPP 2.0.1 or OCPP 1.5 / SOAP are not used for this connection.
2 Required equipment
- OCPP 1.6J‑compatible EV charger, installed and commissioned by a qualified electrician
- Charger connected to the same local network as the Reduxi Controller (Wi‑Fi or LAN via router)
- Access to the OCPP settings of the charger – manufacturer app, local web interface or installer tool
- Reduxi Controller with a static IP address and a matching IP reservation in the router (e.g.
192.168.31.73, see Point 3.3) – the address is also shown in the Reduxi Configurator as Controller OCPP JSON 1.6 URL when you add the device - Charge point ID of the charger (often the serial number – shown in the app, web interface or on the type plate)
- Laptop or tablet with internet access for the Reduxi Configurator
Static IP + IP reservation for the Controller The charger connects to the Controller’s IP address. If the address changes, the OCPP connection is lost. Set a static IP on the Reduxi Controller and reserve the same IP for it in the router (see Point 3.3).
3 System overview & network
The charger opens a WebSocket connection to the Reduxi Controller and identifies itself with its charge point ID. The Controller assigns the connection to the device with the same device identifier and then reads measurements and sends charging limits.
3.1 How OCPP communication works
OCPP is a push protocol: the charger establishes the connection – not the Controller. The charger (OCPP client) opens a permanent WebSocket connection to the Reduxi Controller (OCPP server) and keeps it open. All messages in both directions then run over this one connection: the charger pushes its status and meter values on its own, and the Controller sends its charging limits back through the same channel.
🏠 Local network (same router)
EV charger
OCPP client
1Charger connects to the Controller
opens a permanent connection (WebSocket) – the line stays open
2Charger reports its values – automatically
status · current · power · energy
3Controller sends the charging limit back
e.g. “charge with max. 10 A” (PV surplus / load management)
Reduxi Controller
OCPP server · fixed IP address
The charger always starts the connection (1). Over this open line it reports its values (2) and receives the charging limit (3).
Think of it as a phone call The charger “calls” the Controller and keeps the line open. On this call it reports its values and receives instructions. The Controller cannot call the charger itself – that is why the Controller needs a “phone number” that never changes: a fixed IP address.
| Direction | Messages | Purpose |
|---|---|---|
| Charger → Controller | BootNotification, Heartbeat | Registration after start‑up and keep‑alive of the connection |
| Charger → Controller | StatusNotification, MeterValues, Start/StopTransaction | Charger state, currents, power and energy – pushed by the charger at its own interval |
| Controller → Charger | SetChargingProfile | Charging current limit according to PV surplus and load management |
| Controller → Charger | TriggerMessage, RemoteStart/Stop | Request current values, start or stop a charging session |
What this means in practice The Controller cannot reach the charger on its own – it can only answer once the charger has connected. Therefore the charger’s IP address is not needed in Reduxi, but the Controller’s address must never change (see Point 3.3). If the connection drops, the charger reconnects by itself and uses its fallback current in the meantime.
3.2 Addresses and URL
| Component | Role | Address / setting |
|---|---|---|
| Reduxi Controller | OCPP server (central system) | ws://<Controller IP>/ocpp/1.6/json |
| EV charger | OCPP client (charge point) | Connects to the URL above + its charge point ID |
| Full URL used by the charger | – | ws://192.168.31.73/ocpp/1.6/json/<Charge point ID> |
Unencrypted connection in the local network The Reduxi Controller uses
ws:// (unencrypted, local network only). Some chargers only allow wss:// or require a certificate/security profile – these cannot connect to the Controller locally. Choose WS, security profile 0 or None if offered.3.3 Static IP for the Controller + reservation in the router
Because the charger always connects to a fixed address, the Reduxi Controller needs an IP address that never changes. Do both of the following – the static IP keeps the address on the Controller, the reservation prevents the router from giving the same address to another device:
1
Reserve the IP address in the router
In the router’s DHCP settings (often DHCP reservation, Static lease or Always assign this IPv4 address), reserve an address for the Reduxi Controller, e.g.
192.168.31.73. The Controller is identified by its MAC address – if it uses LAN and Wi‑Fi, reserve the address for the interface that is actually connected.2
Set the same address as static IP on the Controller
In the Reduxi Configurator open Settings → Network and set a static IP address for the active connection (LAN or Wi‑Fi): the reserved IP, subnet mask, gateway (router IP) and DNS server.
3
Use this address on the charger
Enter exactly this IP in the server URL of the charger (see Point 4.2). If the address is ever changed, the server URL on the charger must be updated as well.
Without a fixed address the charger loses the connection After a router restart or when the DHCP lease expires, the Controller may get a new IP. The charger keeps connecting to the old address, Reduxi shows no data and the charger falls back to its fallback current.
3.4 Connection to an external OCPP backend – the Controller as proxy
Most chargers can connect to only one OCPP backend. If a backend is still needed in addition to Reduxi – e.g. a charge point operator (CPO) for billing and RFID or the manufacturer cloud – the Reduxi Controller acts as a proxy: the charger connects only to the Controller, and the Controller forwards the OCPP communication to the external backend and passes its replies back to the charger.
🏠 Local network
EV charger
Server URL = Reduxi Controller
OCPP
local network
🏠 Local network
Reduxi Controller
OCPP server + proxy · controls the charging current
Forwarding
via internet
🌐 Internet
External OCPP backend
CPO / manufacturer cloud: billing, RFID, monitoring
The charger talks only to the Reduxi Controller. The Controller passes the OCPP communication on to the external backend and back.
- On the charger: enter only the Reduxi Controller URL (see Point 4.2) – not the backend address.
- In Reduxi: enter the backend URL (and username / password, if the backend requires them) in the Forward communication fields of the device (see Point 6.2). Use the URL exactly as provided by the backend operator.
- Control stays local: the charging current is set by the Reduxi Controller in the local network – PV surplus charging and load management keep working even if the internet connection or the backend is unavailable.
- Without an external backend: leave the Forward communication fields empty.
4 Configure OCPP on the charger
Menu names differ between manufacturers. The steps below describe the settings every OCPP 1.6J charger needs – look for the matching fields in your charger’s app or web interface (often under Network, Backend, Connectivity or OCPP).
4.1 Enable OCPP 1.6J
1
Open the charger configuration
Connect to the charger via the manufacturer app, its local web interface or the installer tool.
2
Open the OCPP / backend settings
Find the menu for the external backend or OCPP connection. If the charger is currently connected to a manufacturer cloud or another backend, note the existing settings.
3
Enable OCPP 1.6J
Switch on OCPP and select version 1.6 with JSON (WebSocket). Do not select SOAP or OCPP 2.0.1.
4.2 OCPP server settings
Enter the following values. Depending on the charger, the address is entered as one complete URL or split into several fields:
| Field (typical names) | Value |
|---|---|
| Server URL / Central system URL / Backend URL |
ws://192.168.31.73/ocpp/1.6/json/ (Controller IP) |
| or split: Protocol · Host · Port · Path |
WS · Controller IP · 80 · /ocpp/1.6/json/
|
| Charge point ID / Charge box identity / Station ID | Unique ID, usually the serial number, e.g. CP123456
|
| Append ID to URL / Add SN to URL | On – if the charger offers this option |
| Username / Password (Basic Auth) | empty |
| Security profile / TLS / Certificate | None / 0
|
The charge point ID must be at the end of the URL The Controller identifies the charger by the last part of the URL, e.g.
ws://192.168.31.73/ocpp/1.6/json/CP123456. Some chargers add the ID automatically (option “Append ID to URL”), others expect the complete URL including the ID. Make sure the ID appears exactly once – otherwise the Controller cannot assign the connection.Save the settings. The Controller URL is also shown in the Reduxi Configurator (see Point 6.2).
Not connected yet? That is expected The charger is only accepted once it has been added in Reduxi with its charge point ID. Continue with Point 5 and Point 6 – afterwards the charger should show the backend as connected. Tip: if you don’t know the Controller IP yet, do Point 6 first and copy the address from the field Controller OCPP JSON 1.6 URL.
4.3 Further OCPP options
| Option | Recommendation |
|---|---|
| Fallback current / Failsafe current | Charging current used if the OCPP connection to the Controller is lost. Set a value that is safe for the house connection. |
| Authorization / RFID / Free charging | Many chargers activate access management with OCPP. Allow free charging on the charger or set Allow new charging session = Always in Reduxi (see Point 6.2). |
| Phase assignment / Phase rotation | Assignment of the charger phases to the grid phases. Must match the wiring so that load management reduces the right phase. |
| MeterValues interval / Heartbeat | Leave at default; if offered, a MeterValues interval of 10–60 s is suitable. |
| Other backends / cloud | Most chargers support only one OCPP backend. If a cloud backend is still needed, use the Forward communication option in Reduxi instead – the Controller then acts as a proxy (see Point 3.4). |
5 Log in to the Reduxi web interface
The Reduxi Configurator can be opened remotely via the tunnel connection in the Reduxi app or locally in a web browser in the same network. Both lead to the same web interface.
Remote
Reduxi app
Via tunnel connection · works from anywhere
Web browser
In the local network · via IP address or reduxi.local
📱 5.1 Remote via the Reduxi app (tunnel)
1
Open the app and log in
Launch the Reduxi app on your smartphone or tablet and log in with your credentials.
2
Open Reduxi devices
Tap the menu icon (three lines, top left) and select Reduxi devices.
3
Activate the tunnel connection
Switch on the tunnel connection and wait a moment until it is active.
4
Open the configurator
Tap Open configurator. The Reduxi web interface opens.
Activate the tunnel connection
Open configurator
🖥️ 5.2 Locally via a web browser
1
Open the login page
On a device in the same network, open a web browser and enter the Controller’s IP address (e.g.
http://192.168.31.73) or http://reduxi.local.2
Log in
Username:
admin · Password: admin (factory default).
Reduxi Controller login screen
Web interface after login
The charger always connects locally Regardless of how you open the Configurator, the charger itself always connects to the Controller in the local network via
ws://<Controller IP>/ocpp/1.6/json.6 Add the charger to Reduxi
6.1 Basic settings
1
Add a new device
In the left menu under Devices click + Add device.
2
Select type
Device type: EV charger · Type: OCPP 1.6 - JSON.
3
Name and strategy
Enter a Name (e.g. manufacturer and model of the charger). Under Include to strategy keep Energy manager → Regulated devices ticked, then click Next.
Click + Add device in the left menu
Device type EV charger, type OCPP 1.6 - JSON, name and strategy (example)
6.2 Communication settings
| Field | Value |
|---|---|
| Device identifier | Charge point ID of the charger – exactly the ID at the end of the OCPP URL (case‑sensitive) |
| Connector |
1 (for chargers with two outlets: 1 or 2, one Reduxi device per connector) |
| Charger type |
AC (or DC for DC chargers) |
| Energy counter | Default |
| Allocate power to EVSE when EV is not connected | Default |
| Per phase max. current | Auto detect from EVSE or Manual override with the fused current, e.g. 32 A (22 kW) or 16 A (11 kW) |
| Forward communication / username / password / measurements to backend OCPP server | empty – only needed if an external OCPP backend is used in parallel: backend URL and, if required, username / password (see Point 3.4) |
| Allow new charging session | Always |
| Controller OCPP JSON 1.6 URL | read only, e.g. ws://192.168.31.73/ocpp/1.6/json – this is the address entered on the charger (see Point 4.2) |
Device identifier = charge point ID The value must match the ID the charger sends at the end of its OCPP URL character by character. Without the correct identifier the Controller cannot assign the incoming OCPP connection and shows no data.
Device identifier = charge point ID, connector 1, AC (example)
Check the values and click Done to save the device.
Controller OCPP JSON 1.6 URL – click Done to save the device
6.3 Test communication
With OCPP the charger connects to the Controller by itself – no IP address of the charger is needed. Open the device again (Devices → [Charger] → Details) and click Test communication at the bottom right.
“Unable to communicate with device” is normal for OCPP With OCPP the Controller cannot actively ping the charger. The red line in the first box can therefore be ignored. What matters is the box below: Number of devices found must be at least 1 and the Device identifier must show the charge point ID. The final proof are the live values under Last measurements.
Test communication: the window lists the chargers connected via OCPP and their device identifiers (example)
- 1Number of devices found on OCPP – JSON 1.6 shows how many chargers are connected to the Controller via OCPP.
- 2Device identifier must show the charge point ID of your charger. If it does not appear, the charger is not connected – check the OCPP settings (see Point 4.2).
- 3On the charger, the OCPP / backend status should show Connected or Accepted.
- 4Final check: live values and Communication error = OFF (see Point 7).
Connection established If both sides show a connection, the charger is ready. The Reduxi Controller now controls the charging current according to the active strategy.
7 Check the readings
Open Devices → [Charger] → Last measurements:
Last measurements: control type, currents per phase, power, energy and charger state (example)
| Value | Meaning |
|---|---|
| Control type |
Auto = controlled by the Reduxi strategy · Manual · Off
|
| Current L1 / L2 / L3 | Charging current per phase |
| Max. current per phase | Maximum current of the charger (e.g. 32 A) |
| Active power / Max. active power | Current charging power and maximum power (e.g. 22 kW) |
| Import active energy / session | Total charged energy and energy of the current session |
| Communication error | Must be OFF
|
| State name | Current OCPP state of the charger, e.g. AVAILABLE, PREPARING, CHARGING, SUSPENDEDEV
|
✓ Summary
Preparation (Points 1–3): charger with OCPP 1.6J, charger and Reduxi Controller in the same network, Controller with static IP + IP reservation in the router, external backend (if any) forwarded via Reduxi, charge point ID at hand.
Charger (Point 4): enable OCPP 1.6J, protocol WS, server URL ws://<Controller IP>/ocpp/1.6/json/ + charge point ID, no authentication / TLS.
Add to Reduxi (Points 5–6): EV charger · OCPP 1.6 - JSON, device identifier = charge point ID, connector 1, AC, allow new charging session = Always.
Go live (Point 7): charger shows the backend as connected, Reduxi shows live values and communication error OFF.
→ Common issues
| Issue | Solution |
|---|---|
| Charger does not connect / status stays “Not connected” | Check the server URL (Controller IP, path /ocpp/1.6/json/), protocol WS (not WSS), port 80, no TLS / security profile, and that both devices are in the same network. |
| Charger is connected, but Reduxi shows no data | The device identifier in Reduxi must match the charge point ID at the end of the URL exactly (case‑sensitive). Check that the ID is not missing or appended twice. |
Charger only offers wss:// or requires a certificate |
A local connection to the Controller is not possible. Check for a firmware update or a setting for unencrypted OCPP. |
| Connection lost after a router restart | The Controller got a new IP address. Set a static IP on the Controller, reserve it in the router (see Point 3.3) and update the server URL on the charger. |
| Unwanted charging behaviour when the Controller is offline | Set a fallback / failsafe current on the charger (see Point 4.3). |
| Car does not start charging | OCPP often activates access management – set Allow new charging session = Always in Reduxi or enable free charging on the charger. |
| Charging current is not reduced | The charger must support SmartCharging (SetChargingProfile). Check the charger’s OCPP documentation and firmware version. |
| Load management reduces the wrong phase | Check the phase assignment on the charger and in Reduxi (Advanced configuration → “L1/L2/L3 is connected to main feed”). |
| External backend (CPO / cloud) receives no data | The charger must be connected only to Reduxi. Enter the backend URL and credentials in Reduxi under Forward communication (see Point 3.4). |
| OCPP is connected, but control or readings do not work correctly | Possibly a manufacturer‑specific adaptation of the OCPP protocol – contact Reduxi support at support@reduxi.zendesk.eu (see the note below). |
OCPP connected – but it still does not work? Even when the OCPP connection is established and the charger appears in Reduxi, charging control or readings may not work as expected. A common cause is that the manufacturer has adapted or extended the OCPP protocol (e.g. different message contents, unsupported charging profiles or custom configuration keys). This cannot be fixed in the settings. In this case please contact Reduxi support at support@reduxi.zendesk.eu and include: manufacturer and model of the charger, firmware version, charge point ID and screenshots of the charger’s OCPP settings and of Test communication / Last measurements in Reduxi.