For operators and installers
OCPP backend for wallboxes and charge points
Connect wallboxes and charging stations regardless of manufacturer: OCPP 1.6, 1.6 Security and 2.0.1 over WebSocket. On top of that, access, tariffs, compliant billing and roaming — as a platform you can run under your own brand.
What connects, and how
An OCPP backend is the counterpart a charge point talks to — the specification itself calls it a CSMS (Charging Station Management System) since OCPP 2.0.1, and a Central System in 1.6-era documents. The station opens the connection itself, reports state and meter values and accepts commands — authorise, block, set power, unlock. Because OCPP is an open standard, one piece of software can operate charge points from different manufacturers.
- OCPP versions
- 1.6 · 1.6 Security · 2.0.1
- Transport
- WebSocket, TLS
- Manufacturers
- cross-vendor, mixed
- Hardware
- wallboxes and charging stations, AC and DC
- Roaming
- OICP 2.3 · OCPI 2.2.1
- Billing
- metrology-compliant, OCMF
- Payment
- SEPA and card
- Ad-hoc charging
- QR code, no registration
- Scale
- to hundreds of thousands of charge points
Scope
When a wallbox needs a backend
Not every wallbox needs one. As long as one person charges their own car on their own connection there is nothing to attribute and nothing to bill, and a backend is effort without return. It becomes necessary the moment someone else charges and that has to be attributed verifiably.
One wallbox, one person
At home on your own meter: the station authorises, the electricity runs through the household bill. If the connection is tight you need load management — not a backend.
Several users on one site
Staff, tenants or fleet vehicles on the same charge points: every session has to be attributed to an access medium, authorised and billed. That is what the backend is for.
Charging for payment
As soon as money changes hands, German metrology law applies: signed meter values, auditable receipts, retention. A wallbox cannot satisfy that on its own, because the chain of evidence outlives the session.
Publicly accessible
Ad-hoc charging by QR code without registration, and roaming for other providers' cards, both run through the backend — the station knows neither tariffs nor third-party contracts.
Wallboxes already installed and only the backend should change? The hardware stays where it is — what switching a backend involves.
Platform
Under your brand, not ours
For utilities and operating companies the connection is rarely the question — the question is whose name appears on the portal, in the app and on the invoice. With aCharge it is yours.
Your own portal
Operator and customer portal in your identity, on your domain.
Your own tariffs
Pricing per user group, site and time window — maintained by you.
Your own billing
Invoices in your own name, collection included. aCharge does not appear to your customers.
Third-party cards
Roaming over Hubject and OCPI, so other providers' cards work at your sites.
Operated in Germany
Developed in Aachen, operated in German data centres.
Multi-tenant
Several operators, properties or subsidiaries kept apart in one installation.
From the field
What goes wrong when connecting
Five cases that together account for most connection problems. None of them is a protocol fault; they are configuration and expectation faults.
It connects but does not appear
Almost always the identity configured in the charge point does not match the one the backend expects. Check the ChargePointId, case included.
The connection drops regularly
Typical on mobile connections with a NAT timeout. A shorter WebSocket ping interval in the station usually resolves it.
TLS fails
With OCPP 1.6 Security, older firmware trips over missing intermediate certificates or a badly wrong clock in the station.
Meter values missing from billing
The station sends MeterValues not at all or too rarely. A start and end value is not always sufficient for compliant billing.
The cable stays locked after charging
Usually the station ends the session locally but the backend never learns of it and holds the transaction open. Remote unlock helps immediately.
Next
Depending on what you are working out
Frequently asked