An illegal pedicab set off a three-alarm fire in a Midtown parking garage when its battery likely exploded on Friday, authorities said.

The motorized rickshaw was parked in the basement of a garage near the corner of East 54th Street and Madison Avenue in an area specifically designated for off-duty pedicabs when it spontaneously burst into flames around 10:40 a.m., sources said.

Firefighters upgraded the call to a three-alarm fire when flames began to spread to the surrounding pedicabs.

It took 145 firefighters an hour and a half to put out the fire, although no cars were caught in the blaze, sources said.

Lazy pedicabbies often install golf-cart-like motors under their passenger seats so they can work longer hours without tiring out, even though city law bans adding electric or motor-operated mechanisms to the rickshaws.

Motorized rickshaws that travel at faster speeds are more likely to get into accidents, the city contends.

During another fiery incident in September, a pedicab burst into flames when its illicit motor overheated on a hill in Central Park.