The Definitive Open Solution for EV Charging

Prism is the first commercial charging station that offers full, hassle-free control over the entire charging process. Prism offers a higher quality-to-price ratio than other products currently available on the market. And, most importantly, it is the only device of its kind that benefits from the flexibility of an open architecture.

Universally Compatible

Prism supports charging through a Type 2 socket (commonly referred to as a Mennekes plug) and is therefore compatible with all newer electric vehicles sold in Europe. A version with a Type 1 connector is available for those who need to charge older vehicles. And, if your vehicle has neither a Type 1 nor a Type 2 socket, third party adapters are easy to find. With support for all standard protocols, Prism gives you all the tools you need charge your electric vehicle or to develop new ideas for sustainable mobility.

Extensive Management System

Our goal is to give you full control over the process of charging electric vehicles. Prism includes a user-friendly interface, which you can access through your browser or using a mobile app. It provides access to all of the settings you might need to manage the charging process and monitor related information. It also displays usage data and offers real-time control over charging schedule and power. Prism can communicate with other devices and software using standard protocols such as MQTT and OCPP 1.6, or by means of a simple hub-and-spoke configuration. You can also integrate Prism into your home automation ecosystem.

• Have an electric vehicle that lacks the ability to set its own

charge limits? Program Prism to stop charging at 75% or whatever fraction of "full" you deem optimal.

• Need an easy way to reconfigure your charger? Record *knocking

command* sequences to trigger customized behavior. Knock on Prism four times to set a charge limit of 80%, for example, or knock once and revert to 100%. Even if you’re wearing gloves and your hands are full of groceries.

• Want your vehicle to draw power only if the rest of your household energy

consumption is below a certain threshold? Or to charge only from what you generate through photovoltaics? These are just a few of the ways you can customize Prism.

Available for Developers and End Users

We are offering Prism in four different configurations. Check out Prism or Prism Double if you are looking for a fully-assembled charging station, with an enclosure, that is ready to use right out of the box. If you want to build your own enclosure, you probably want the Prism Core EV Kit. And if you’re a developer, have a look at the Prism Core Starter Kit, which includes a control module – all of the Prism boards assembled inside a custom DIN box – but does not include the industrial contactor, the residual current monitor, an EV charging cable, or an enclosure.

• For End-Users: Prism and Prism Double are complete solutions, ready to begin charging your electric vehicle – or vehicles – as soon as they arrive. Prism is available either as single-phase charger, capable of up to 7.5 kW of AC power, or as a three-phase charger, capable of up to 22 kW of AC power. Prism Double is single-phase only. Both Prism and Prism Double are available in black or red, and include your choice of a two, five or seven meter cable with either a Type 1 or a Type 2 connector. Prism Double includes two such cables and can charge two vehicles simultaneously.

• For Developers: The Prism Core Starter Kit and Prism Core EV Kit allow you to experiment with software related to electric mobility. They are designed to communicate with all of the devices involved in energy production and consumption: from photovoltaics (PVs) to the storage system to the vehicle itself. With the Prism Core Starter Kit, you can develop improvements to the charging management process, extend the user interface, or integrate Prism into a home automation setup, to name just a few potential areas of innovation. The Prism Core EV Kit adds a 63 A contactor, an RCD cable, and an EV cable with connector. It is, essentially, a Prism without the enclosure and the internal high current wiring.

Features & Specifications

Prism includes an embedded Linux system, a versatile MCU for realtime processing, flexible networking options, a robust collection of power-management technologies, and an addressable RGB LED strip – all in a compact, high-design enclosure built for safety, durability, and "wall appeal."

Safe, Durable and Compact

Prism is designed for safety. It includes an electronic Residual-Current Device (RCD) that detects current leakages and an I²C bus that can be used in conjunction with one or more temperature sensors to help prevent fires. It accommodates temperatures anywhere from -20° to 55° Celsius (-4° to 131° Farenheit) and satisfies IP54/IK08 physical protection standards.

Technical Specifications

• Embedded Linux System: 540 MHz, 128 MB RAM, 32 MB of flash
• Realtime Processing: STM32 MCU
• Connectivity: Ethernet, Wi-Fi, and support for OCPP communication protocols
• Power meter: ATM90E36 with Fourier analysis functions to measure voltage, current, THD, DFT, and mean power
• Industrial Contactors: Rated to 63 A
• Current Leakage Sensor: RCM14
• Integrated Power Supply: 20 W
• Input Voltage
  • Single-Phase: 110/230 VAC ± 10%
  • Three-Phase: 400 VAC ± 10%

• Nominal frequency: 50 Hz/60 Hz

• Metering: Class B - EN50470

• Overvoltage Protection: CAT III

• Residual Current Detection: 30 mA AC, 6 mA DC

• Physical Protection: IP54/IK08

• Working Temperature: -20° to 55° Celsius (-4° to 131° Farenheit)

Prism Flowchart

Comparison Table

* - Hardware and firmware are open and documented but sources will not be available at launch

A Note on Certifications

Prism is designed to meet EU regulatory requirements and is CE certified, but it has not been tested for the US market. We suggest that US backers choose the Core Starter Kit. It was designed for 110 V Live-Neutral systems, at up to 32 A, but it should be easy to adapt for 240 V split phase systems. Current can be increased using larger current transformers and contactors.

Support & Documentation

Please visit our Hackaday.io page to learn more about the software elements of Prism, to make suggestions, or to let us know about any issues you might encounter.

Manufacturing Plan

We are using a Chinese OEM manufacturer for Prism PCB assembly. Cables, enclosures, plastics and other minor components, such as screws and grommets, are from EU suppliers. We prepare, calibrate, and test each board at our headquarters in Padova, Italy, before assembling them and packing both Prism Core and Prism units for delivery.

Fulfillment & Logistics

Prism ships free worldwide, and all prices include VAT and other regional sales taxes. All European orders will be shipped directly from Cartender in Italy. Crowd Supply will fill all other orders from their facility in the United States. If you have questions about fulfillment, please see the Crowd Supply Guide first, then contact Crowd Supply directly if the Guide does not answer your question.

Risks & Challenges

We have already begun production of the first batch of Prism and Prism Core units. All components and materials have already been shipped to our headquarters and are currently undergoing test and assembly. We see no particular risk in this phase.

Who is Cartender?

The production of electric vehicles continues to expand, bringing with it a range of choices for customers. Many charging related products have appeared on the market, but one is still missing: an open solution for residential and commercial charging. We saw this as an opportunity, back in 2016, so we began working on Prism. We have developed a number of hardware prototypes since then, and our software has steadily improved. Now on our third iteration of Prism, we believe we are ready to enter the market. And, given the open nature of the project, a Crowd Supply campaign feels like the perfect way in which to do so.

At Cartender, we are passionite about products that contribute to sustainable mobility. We have worked in the automotive industry for years and, over that time, have gravitated toward projects that promote energy efficency. We know that electric vehicles are increasingly necessary, and we see that they are increasingly popular. We believe they will be part of our future, and we want to give users more control over that future.