Honest advice first: this is one for your electrician. CTEK configuration happens over a USB cable plugged directly into the controller board inside the unit, which means opening the charger up. If your CTEK is being professionally installed, hand your installer this guide and the job gets done on install day. There are more settings to check than on most brands, but every one of them is listed below.
What's needed
A laptop (Windows needs CTEK's CCU driver installed first, from CTEK's website; Mac and Linux work out of the box)
A USB cable to the mini USB port on the controller board
About 30 minutes
1Add the charger in your GuestCharge dashboard
Run the onboarding wizard with the charger's Chargebox Identity before the configuration session.
2Connect and open the web interface
With the USB cable connected between laptop and controller board, open a browser to http://192.168.7.2 and log in with username ccu, password ccu.
3Enable advanced settings
Select Configuration from the left menu, then the Setup tab, and switch on the Advanced settings toggle.
4Set up the internet connection
Open the Interface tab. From the WAN dropdown select Wired, then open the Wired subsection and set the Configuration Method to DHCP. If your router doesn't support DHCP, enter the network settings manually. Save.
5Enter the GuestCharge settings
Go to the Backend tab:
Chargebox Identity: leave it exactly as it is. Don't edit this field, but check it matches what was entered in the onboarding wizard.
Communication Protocol: OCPP-J 1.6
Backend Endpoint:wss://ocpp.guestcharge.co/ followed by the Chargebox Identity shown above the field, like wss://ocpp.guestcharge.co/ABC12345
Save.
6Set the authorisation settings
Open the Authorization settings sub-tab and set each one as follows. These control how the charger decides whether a session is allowed, and getting them right is what makes guest billing work properly:
Stop transaction on invalid ID: On
Authorization Cache: Off
Authorize Remote Tx Requests: On
Allow Offline Tx For Unknown Id: Off
Local Authorize Offline: On
Local Pre Authorize: Off
Allow Offline Tx Without Id: Off
Local Authentication List: On
Click Save.
7Enable the RFID lock
Go to the General tab and make sure RFID lock is enabled, then Save. This matters: without it, the charger would let anyone charge without going through billing at all.
8Set the authentication mode
Go to Outlets and check the Authentication Mode is set to RFID. If it shows Open, change it to RFID and Save. Open mode means free, unbilled charging for anyone who plugs in, which defeats the point.
9Restart and check
Reset the charge point when prompted, then open the Status section from the left menu. Both Backend connection and WAN connection should show as established.
How you know it worked
Status shows both connections established, and the charger shows as connected in your GuestCharge dashboard.
If it won't connect
Check the backend endpoint and Chargebox Identity
Confirm the wired network connection is live (the WAN connection line in Status tells you)
Re-check the authorisation settings against the list in step 6. A single wrong toggle can leave the charger connected but refusing or mishandling sessions.
Still stuck? Email the Chargebox Identity to team@guestcharge.co and we'll check from our side.