Another e-bike rider — the third in as many weeks — has died under unclear circumstances involving no other vehicles.

In the latest case, according to the NYPD, Cheng Wang, 26, was riding his electric bike southbound on Ralph Avenue on Jan. 6 at around 2:45 p.m. when he simply lost control of the bike “for unknown reasons and fell to the ground,” which caused internal — and ultimately fatal — injuries.

Wang was taken to Brookdale Hospital, where he died the next day.

An NYPD spokesman said that cops obtained video from the crash scene — which is in front of school bus company yard in an industrial area with choppy pavement — that showed clearly that no other vehicles were involved in the crash. The victim fell off the bike just a few feet before a trestle for a freight train line, though it is unclear if the dark underpass played a role.

It’s the third time in as many weeks that cops have said an e-bike rider simply fell off his bike and killed himself.

Last week, cops said a still unidentified cyclist fell off his bike on E. 149th Street in the Bronx — and the Daily News confirmed the police account in a video that showed the cyclist losing control, though it is unclear if he hit a pothole or other debris (the video does not show the roadway itself).

And late last year, cops said Alejandro Santos rode his bike directly into a truck on dangerous Third Avenue in Brooklyn. Again, police did not provide any information about the condition of the roadway or whether Santos ran into a double-parked vehicle.

In any event, a police spokesman said that the NYPD will investigate the cause of Wang’s death.

“We will go back to see if there was a pothole or any other explanation,” the spokesman said. “We don’t want this to happen again.”