Clear Definition
DIN SPEC 70121 and ISO 15118 are both communication standards used in CCS charging systems, but they are not the same.
DIN SPEC 70121 is an earlier communication specification mainly used for basic CCS DC fast charging. ISO 15118 is a more advanced international standard that supports smarter functions such as Plug & Charge, secure communication, smart charging, and future V2G applications.
Application Scenarios
Scenario DIN 70121 ISO 15118
Basic CCS DC charging Suitable Suitable
Plug & Charge Not suitable Suitable
Smart charging Limited Stronger
AC charging communication Not the main scope Supported
V2G / bidirectional charging Not suitable ISO 15118-20 supports advanced V2G
Future charging projects Limited More future-ready
Technical Flow Difference
DIN 70121 Flow
Plug in
→ CP / PP detection
→ PLC communication
→ Basic charging parameter exchange
→ Pre-charge
→ DC charging
→ Stop charging
ISO 15118 Flow
Plug in
→ CP / PP detection
→ PLC communication
→ Protocol negotiation
→ Secure communication
→ Authentication
→ Charging schedule / parameter exchange
→ Charging or bidirectional power transfer
→ Session management
Product Relationship Diagram
CCS Charging Station
|
v
SECC
| |
| DIN 70121 | ISO 15118
v v
Basic DC Charging Smart Charging / PnC / V2G
Comparison Table
Item DIN SPEC 70121 ISO 15118
Type German technical specification International standard
Main application CCS DC charging AC/DC smart charging
Communication PLC-based CCS communication PLC-based advanced communication
Plug & Charge No Yes
Security Basic Stronger security design
Smart charging Limited Supported
V2G No Supported through ISO 15118-20
Project positioning Basic compatibility Future-ready charging system
Standard Protocol Explanation
DIN 70121 is still important because many existing CCS vehicles and chargers support it. However, for new-generation charging infrastructure, ISO 15118 is more important because it supports advanced functions.
A practical charging station project may need to support both:
DIN 70121 for basic vehicle compatibility
ISO 15118-2 for Plug & Charge and smart charging
ISO 15118-20 for future V2G and bidirectional charging projects
FAQ
Q1: Should my charger support DIN 70121 or ISO 15118?
For CCS DC chargers, supporting both is often better for compatibility.
Q2: Is DIN 70121 outdated?
It is older and more limited, but it is still used in many CCS charging scenarios.
Q3: Is ISO 15118 required for Plug & Charge?
Yes. Plug & Charge is based on ISO 15118 communication and certificate mechanisms.
Share Charging Project Capability
Share Charging can help customers choose the right protocol strategy for CCS2 charging projects. For example:
Basic DC charger: DIN 70121 + OCPP
Smart DC charger: DIN 70121 + ISO 15118-2 + OCPP
Future V2G charger: ISO 15118-20 project evaluation
European charging station: CCS2 connector + SECC + EVSE controller + OCPP platform
This helps customers avoid choosing a protocol stack that is either too simple for future needs or too complex for the current project budget.
