The $100 model boat Rachel Gibbs bought for her son exploded after being on charge for 30 minutes.

A mother was shocked when a $100 Christmas present for her son exploded, leaving her kitchen covered in black ash and stinking of smoke.

Rachel Gibbs bought three remote-controlled boats for her 20-year-old son from electronics retailer Jaycar in Auckland's North Shore suburb of Glenfield, just two days before Christmas.

After charging the Mini RC Race Boat for 30 minutes of the 3.5 hour advised charging time, her son noticed a burning smell and took a closer look, she said.

Gibbs said it was lucky her son had just moved the toy from his face when it exploded, leaving behind a dent in her kitchen windowsill.

"He'd only just moved it away from his face when the battery exploded and came flying out of the side."

READ MORE:

* Charging battery bursts into flames

* Charging hoverboard catches fire, destroys Melbourne home

The lithium batteries were already inside the boat when it was purchased, Gibbs said.

Supplied The battery shot out of the side of the model boat, leaving a hole and the smell of smoke and black ash all through their kitchen.

Gibbs said Jaycar offered her a refund, but told her they would not be advising other customers of the issue.

"It isn't about the money, I'm not worried about the money, I'm worried about people's safety," she said.

The motorised boat is advertised on the Jaycar website now for half the price Gibbs paid.

Jaycar duty manager Alfred Moses said Jaycar will be investigating the explosion, and if the product is deemed unsafe it will be recalled immediately.

Moses said batteries which come in such products are usually not old, and this kind of explosion is typically caused by overcharging.

"It doesn't seem like a fault with the product because she bought three, and the other two are fine," he said.