Background Information

A Wallbox is an electric car charging point which takes the form of a wall-mounted box. It can be installed in a private garage or an apartment block or company parking lot.


Producing own green energy from e.g., solar panels has become very popular in the last years in Germany. In addition, due to more electric cars, the use of private wallboxes for charging has also increased substantially in the last years. If the solar panels are connected to the public electricity grid, the electricity that is unused by the private household is compensated by a much lower rate than the rate for consuming electricity from the public grid. Therefore, it would be great to have the chance to sell the produced energy directly to another consumer at a higher price than the price for providing the electricity to the public grid. Additionally, due to higher popularity of electric cars there is often a lack of charging infrastructure in cities, some consumers decide against buying electric vehicles because of this. This issue will even increase in the future, thinking about autonomous driving electric cars which would benefit a lot from an intelligent power grid including charging infrastructure. So multiple problems can be addressed at once by providing a platform for consumers and private electricity producers, where a higher compensation and a better availability of charging infrastructure can be achieved. Autonomous driving cars can benefit even more from a higher availability of charging spots. For example Robotaxis could navigate to the next available private spot when cheap charging is available and nearby, e.g. when there is a lot of sun during the day.

What it does

The platform connects private wallbox owners with private or public electricity consumers. As a wallbox owner you can decide on which time of the day the charging (and parking) spot is available and for which price you are willing to sell your electricity (supported by a smart pricing algorithm). The charging spot can then be found by other users in the system. They can search for the next available charging spot nearby and reserve it for some time in advance. Thereby, the charging infrastructure has much better usage, the private electricity producers receive a higher compensation and there are much more charging stations and parking lots available.

How we built it

After an exiting brainstorming session to form our idea, we started with creating a user story and designing wireframes all together to ensure a common understanding of WALLE and to lay the foundation for the upcoming programming. We then compiled to-dos and distributed them in such a way that each team member could profitably use his or her skills. This approach allowed us to simultaneously work on logo and design, polish the concept and user stories, prepare the presentation, and implement the App in React Native. Throughout the hackathon, we stayed in contact via Discord to keep each other updated, discuss and prioritize new ideas and solve any issues that arose as quickly as possible.

Challenges we ran into

The biggest challenges we ran into, were to choose the most relevant features to be implemented in the given amount of time from a vast amount of ideas, as well as combining our different skillsets to make the most profitable use of our resources. From a technical point of view the most challenging part was to find out how wallboxes work and how they can be integrated into WALLE to enable communication between WALLE and the wallbox. We found out that older models can only be adapted accordingly with major adjustments. However, smart wallboxes are becoming more and more popular and these models can be easily integrated into WALLE. Here, a connection via an API (LAN or WLAN) or via Modbus (TCP or RTU) is possible. For our purposes, the former is particularly suitable. Unfortunately, we did not have a wallbox available for the duration of HackaTUM and could not showcase the integration of the wallbox in WALLE. We would love to try this out in the future.

Accomplishments that we're proud of

We are very proud of what we accomplished in such a short period of time, although most of our team members did not know each other before HackaTum. We definitely grew together as a team and were able to experience how our knowledge can be combined to create great things. Also, we are very enthusiastic about WALLE and would love to continue the project to see our WALLE grow as we belief that it does not only help to solve the problem of efficient energy use in the field of electric cars but also encourages people to use greener power and share resources to enable an ideal power balance.

What we learned

Having a team of motivated people coming from different backgrounds can be challenging at first, but it is great to have this variety of skills for all the different tasks which need to be addressed during the hackathon. Regarding the ideas, it is important to prioritize those ideas that can be achieved during the short amount of time to present a first working prototype. Besides that, all other ideas are consolidated on a concept board for later use.

From the technical side of things, we were able to learn a lot about electric cars, robotaxis and wallboxes in a short amount of time. In addition, we were all able to brush up on our usability and programming skills and had a lot of fun working together on WALLE.

What's next for WALLE

As a next step we want to create a running prototype of the WALLE app including an integration for existing wallboxes to connect them to the mobile app. When this is achieved, we would need to get more people on the platform to try it out in a first beta phase. During this phase it would also be interesting to have first conversations / experiments with autonomous driving cars and robotaxis. Furthermore, we would like to add more features to WALLE. The following features are up next:

Offer your Wallbox Due to a short time limit, there is no feature for wallbox owners to offer their wallbox in WALLE at the moment. We would like to add this feature as soon as possible.

Smart Algorithm for Price Calculation Calculates the price for each kWh based on the amount of energy available, demand, location and charging speed of the wallbox. As a wallbox owner you can define lower price limits. This leads to an overall higher efficiency of the green electricity grid and a more sustainable energy use.

Statistics We would like to add statistics to show users statistics on how sustainable their booked wallboxes are and how much CO2 they safed by choosing sustainable options to fuel their cars.

Payment Integration Users should be able to use common payment methods such as PayPal, Credit Card, Apple Pay, Google Pay. The amount of charged energy is sent from the wallbox to the WALLE, which then calculates the price. And initiates the payment process.

Wallbox Ratings Users can rate wallboxes on a scale of 1 to 5 stars to allow other users to see how other users experienced the respective wallbox and if there are any problems with the wallbox.

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