Fundamentals
What is a CPMS?
Charge point management system. The software that turns charge points into an operation: access, tariffs, billing, monitoring. What belongs to it, what does not, and how to recognise a usable one.
In short
A CPMS (charge point management system) is software that centrally operates charge points for electric vehicles. It controls who may charge, at which tariff a session is billed, and what state each charge point is in. It connects to the hardware over the open OCPP protocol, which is why one CPMS can operate charge points from several manufacturers.
Scope
Four jobs every CPMS has to do
Everything else is optional equipment. If one of these four is missing, it is a monitoring tool rather than a CPMS.
Access
Who may charge where — by RFID card, app, QR code or anonymously ad hoc. Without access control a charge point is an open socket.
Tariffs
Prices per user group, time window or site. Staff pay differently from guests, and both have to see the price before the session starts.
Billing
Attribute every kilowatt-hour and turn it into an invoice that holds up. In Germany that means metrology-compliant (Eichrecht).
Operation
State, faults, remote unlocking, firmware. A charge point whose failure nobody notices is not a charge point for several weeks a year.
Distinction
Two systems that get confused constantly
The most common purchasing mistake is assuming one piece of software does both. They can come from one supplier, but they do not have to, and the choice should be deliberate.
The practical difference: one keeps running on site when the internet connection drops. The other does not, and does not have to, as long as it reconciles the sessions afterwards.
| CPMS | Load mgmt. | |
|---|---|---|
| Decides | who, and at what price | how much power |
| Runs | in the cloud | on site |
| If offline | reconciles later | keeps regulating |
| Protocol | OCPP | Modbus TCP, OCPP |
| At aCharge | aCharge Cloud | TELECONTROL / DYLAMO |
When comparing
Six questions that make the difference
Every supplier has the basics. Differences show up in the places datasheets rarely mention.
Which OCPP versions?
1.6 is the market standard, 2.0.1 the future. Supporting only 1.6 limits the hardware you may buy later.
Eichrecht included?
In Germany metrology-compliant billing is mandatory, not optional, as soon as you bill per kWh.
Who collects the money?
Any system can generate invoices. The difference is whether collection by direct debit or card is included.
Ad-hoc charging without an app?
Mandatory at public charge points under AFIR — and the most common complaint from guest users.
Roaming via which hubs?
One hub or several decides how many third-party charging cards work at your site.
White label possible?
The decisive point for utilities: does the installation appear under your name or the software vendor's?
In Germany
Three rulebooks that narrow the choice
Systems that look comparable internationally regularly drop out here, because they do not meet requirements that do not exist in this form elsewhere. Check these three before comparing feature lists.
Mess- und Eichgesetz
Billing per kilowatt-hour requires verifiable measurement: signed meter values, usually in OCMF format, permanently checkable by the person billed. A CPMS that simply copies a number into an invoice does not meet this.
EU-Verordnung 2023/1804
At publicly accessible charge points, ad-hoc charging must be possible — no contract, no app install, with a common payment method. “Publicly accessible” is broader than many operators assume.
Netzdienliche Steuerung
Charge points count as controllable loads that the grid operator may temporarily limit. That is primarily a load-management matter, but it has a CPMS side: the reduced session still has to bill correctly and remain explainable.
Vocabulary
Who is actually who in a quote
These abbreviations appear in almost every quote and are rarely explained. They determine who owns the charge points, who invoices, and who is answerable for the metering.
- CPO
- Charge Point Operator — runs the charge points technically. If you operate charging on your own property, you are the CPO whether or not you call it that.
- EMP / MSP
- E-Mobility Provider — issues the cards and apps to drivers and bills them. Through roaming, one EMP's card works at other CPOs' charge points.
- MSB
- Metering point operator — answerable for the calibrated meter. Often the grid operator, sometimes a third party.
- Roaming-Hub
- Mediates between CPOs and EMPs so third-party cards work. Hubject (OICP) dominates in Germany, alongside the open OCPI standard.
One example
aCharge Cloud is one such system
Developed in Aachen, operated in Germany, built to scale from one site to hundreds of thousands of charge points. Charge points connect over OCPP 1.6, 1.6 Security and 2.0.1, every session is billed compliantly, and it can be run under your own brand.
Billing and metrology law
How kilowatt-hours become invoices — and why the hardware decides whether they can.
aCharge Cloud
Access, tariffs, billing and roaming — under your own brand.
The OCPP connection in detail
Versions, security, supported hardware and what goes wrong when connecting.
Frequently asked