The 2025 Badge and Its 18650 Battery: An Examination
The latest edition of the What Hackers Yearn (WHY) event, held in Noord-Holland, north of Alkmaar, has seen concerns over the fire safety of its badge. The badge's design and the unprotected 18650 battery cells supplied with it have been identified as a significant fire hazard.
The issue lies in the design of the battery power traces on the PCB between the battery holders and the power supply circuitry of the WHY 2025 badge. The positive and negative battery traces have a too-tight gap, protected only by soldermask, which is insufficient. This creates a risk where metal could short the battery terminals, causing batteries to short circuit, leading to dangerous overheating and a potential fire.
The RevSpace hackerspace in Leidschendam issued a detailed warning, stating that the badge’s design combined with unprotected Lithium-ion cells (18650) could easily lead to a fire hazard. They advise not to install the supplied cells in the badge, recommending returning them to the badge tent or storing the cells safely in a non-conductive container if retained. Using an external USB power supply instead is considered safer since it often includes standard protections.
In response to the concerns, the event organizers have added a printed disclaimer leaflet warning against the misuse of the cells and have added a last-minute epoxy coating to the boards for additional protection. However, they have not recommended the use of external power sources.
The concerns about the WHY 2025 badge are not new. The original Dutch badge team resigned en masse at the start of the year following a disagreement with the WHY2025 organizers. The event was the latest in a series of four-yearly events from the Netherlands.
Some users have taken matters into their own hands, 3D-printing cases to help reduce the risk of short-circuiting due to foreign metal objects.
The WHY organizers have been made aware of the risks, with a formal warning being issued on July 20, 2025. The safety warnings have been prominently discussed in Dutch technical media since early August 2025.
In conclusion, users are strongly advised not to use the supplied batteries in the WHY 2025 badge. Using external USB power is a safer alternative. The issue has been publicly acknowledged and covered since July/August 2025.
The concerned issue with the WHY 2025 badge's safety stems from the design of the battery power traces on the PCB, specifically the too-tight gap between the positive and negative battery traces. This gap, protected only by soldermask, creates a risk of short circuits leading to overheating and potential fire, highlighting the need for caution when handling the gadget's battery. To mitigate the risk, RevSpace hackerspace recommends not using the supplied batteries and instead opting for an external USB power supply as a safer alternative.
