A “well mannered and respected” teenager was killed when he crashed his e-bike into a telegraph pole at about 26mph, just four days after getting it.
An inquest heard Jamie Jones, 17, was riding on a roadside cycle path when the collision happened.
Experts said Jamie's bike was illegal to ride without a licence as it had a max speed of around 70mph.
The inquest, held at Ruthin County Hall, heard the bike's battery had a power output of 8,000 watts - 32 times above the UK legal limit.
But investigators could not find a reason for the crash in Deeside, North Wales, which was captured on CCTV.
Jamie's mother, Jane Clutton, described her son as a "very well mannered, well known and well respected" young man who was an "incredibly bright and talented individual".
She added: "His death has left a massive hole in our family.”
The inquest included footage of Jamie's bike veering from the path and into the telegraph pole at about 4.55pm on December 17, 2021.
Jamie was taken to hospital, but was found to have already suffered cardiac arrest and could not be saved.
Advanced forensic examiner Gary Roberts, of North Wales Police, inspected the bike after the crash and found it was a replica of a Stealth Bomber model, but without identification plates.
Mr Roberts said the bike had an 8,000-watt battery and was illegal to ride without a valid licence and third-party insurance.
For an electric bicycle to be legal in the UK, its power output must not exceed 250 watts.
Mr Roberts found the bike's rear brakes were faulty, but should not have played a part in the crash and there were no other mechanical defects.
He said: "Jamie had no reason to brake at that time."
Collision investigator Gordon Saynor said the weather at the time of the crash was fine and dry with clear visibility and a good road surface.
He told the Ruthin hearing there was no evidence of any third-party involvement and no forensic evidence as to what caused the collision.
Mr Saynor said tracking data from Jamie's phone estimated he was travelling at about 26mph at the time of the crash.
A pathologist found Jamie's death was caused by massive internal blood loss caused by trauma to the abdomen and thorax with no evidence of drugs or alcohol in his system.
Coroner Kate Sutherland recorded a conclusion of accidental death.
