The demand for e-bikes has doubled nearly every year since 2015. Recognized bike brands like Trek and Specialized were quickly joined in the market by smaller brands like Aventon, RadPower and Tern. Established as well as some newer bike brands source parts from suppliers that are vetted for quality and safety, and must meet strict standards for battery charging and overall performance. However, many off-brand e-bikes and e-bike conversion kits found online source low-quality parts and may be produced with low or non-existent quality control.
Cheap electronic batteries and electrical systems may not include safety technologies for preventing thermal runaway — a phenomenon in which the lithium-ion cell enters an uncontrollable, self-heating state — that can result in batteries overheating and causing fires.
