A London pensioner died in a house fire caused by an over-charged battery on a converted e-bike, an inquest has found.
Bobby Lee, 74, suffered severe burns and inhaled toxic smoke when the blaze broke out at his home in Woodyard Close, Kentish Town in July last year.
An inquest heard the lithium battery on a mountain bike - which had been converted into an e-bike – combusted after being left on to charge by one of Mr Lee’s relatives.
Efforts to evacuate the pensioner from his ground floor bedroom failed, and Mr Lee died at the scene on July 6.
Assistant Coroner for Inner North London, Ian Potter, has now issued a ‘prevention of future deaths’ report, warning of the dangers of e-bike conversion kits.
He said there were at least 169 fires in London last year which have been blamed on e-bikes, and Mr Lee was among three people to die in 2023 as a result of e-bike fires.
The coroner said the fire at Mr Lee’s home broke out at just before 7am, and was “caused by the over-charging of a lithium-ion e-bike battery that had no battery management system in situ”.
He continued: "The e-bike from which the battery came, was owned by another member of the household. The bicycle had started off as a regular mountain bike, but was subsequently fitted with a ‘conversion kit’ which converted the bicycle into an e-bike.
"The e-bike was purchased second-hand, without a charger. A charger was subsequently purchased from an online marketplace.”
The coroner heard evidence from fire safety experts that the charger was unsuited to the lithium battery fitted to the bike, having a different voltage rating, and there was no battery management system to prevent over-charging.
“Lithium-ion batteries sold as part of so-called e-bike conversion kits tend to be of a significantly inferior quality and construction when compared to the battery packs manufactured and installed in purpose-built e-bikes”, Mr Potter wrote in his report.“Lithium-ion batteries sold as part of e-bike conversion kits are regularly sold/supplied without a charger, thereby increasing the risk of an unsuitable charger being purchased and used.“Chargers for sale on online marketplaces, in particular, regularly fail to meet appropriate standards. In this case, the charger purported to carry the European ‘CE’ mark, which should be an indication that the product conforms to European health, safety and environmental protection standards; however, the Fire Investigation Officer noted that the mark was slightly different and therefore not genuine. It was used instead to denote ‘Chinese Export’."The presence of universal charging connectors across batteries of different voltages means that there is a significant risk that over-rated chargers can be inadvertently connected to lower power batteries, which was the case in the fire that led to Mr Lee’s death."There is currently no British or European (e.g. BSI or PAS) standard specific to e-bike conversion kits and/or chargers and consequently it is relatively easy for people to buy, particularly from online marketplaces, e-bike conversion kits and/or lithium-ion batteries that are not of sufficient quality or otherwise not of an appropriate standard to charge safely. "There is an increased risk of people mixing and matching lithium-ion batteries with chargers that carry a different voltage rating."When a lithium-ion battery is charged using a charger with a different voltage rating, this can lead to thermal runaway and catastrophic failure of the battery – a build-up of heat, failure of one of the cells within the battery, followed by a chain reaction as the remaining cells fail, all of which can happen very quickly and explosively with the emission of sparks and toxic, flammable vapours."
The coroner also pointed out that, as a result of past deaths, the government’s Office for Product Safety and Standards had promised to create standard safety regulations for e-bike conversion kits.
But he added: "To my knowledge this piece of work has not yet been completed."
The Office for Product Safety and Standards has been ordered to respond to the coroner’s report within 56 days.
