Batteries and battery-powered devices taken on planes could be a danger if they are not packed properly the Civil Aviation Authority (CAA) has warned.

The warning comes after fires, caused by the short circuiting of batteries occurred on a number of passenger aircraft's.

The CAA said that although the dangers to batteries stored in electronic gadgets such as notebooks, mobile phones and MP3 players were minimal, it warned that loose batteries posed a danger.

This is because they could be short-circuited if their terminals (marked + and -) were bridged by an everyday metal object, for example a coin or jewellery, which are often left loose in bags and pockets.

The CAA's concern was shared by Richard Poate, battery certification manager at TÜV Product Service.

“Lithium-ion batteries such as the ones found in mobile phones, can pose a small danger as they have been created to be small powerful devices that can drive power hungry functions such as bluetooth and multimedia applications,” he told Computeractive.

“AA alkaline batteries [such as the ones found in radios or remote controls] can also pose a risk if they are mishandled or placed in a pocket or bag with loose change.”

However, he reassured people that the chances of a major explosion caused by short circuiting or air pressure were “slim” due to the tests that are routinely carried out to make sure that Lithium-ion batteries conform to applicable standards such as the UN Manual of Test & Criteria, which ensure that batteries are safe for transportation. This includes testing for vibration, the risk of short circuiting and also how a battery copes with the change in altitude.

He also advised that the dangers of a fire onboard could be prevented further by through some simple steps.

“By taking a few precautions such as buying original accessories and batteries instead of replica’s, the public can ensure they minimise short circuiting risks as these products should conform to all the safety features,” said Mr Poate. 

Geoff Leach, manager of the CAA's dangerous goods office, advised people not to carry cheap, unbranded batteries in travel bags.

“Although they appear the same as the batteries they imitate, they do not have the necessary safety features. Batteries should only be bought from reputable sources,” he said.

He also advised travellers to keep spare batteries in their original packaging as this has been designed for transporting. “If original packaging is not available, insulate the terminals so they cannot come into contact with other metal objects.

“[People] can pack each battery in its own protective case, resealable plastic bag or package, or cover the terminals with insulation tape,” he added.

In May 2006, the CAA claimed a spare notebook battery that had been stored in a carrying case caught fire whilet the aircraft was waiting to depart.

This was followed more recently in February 2007, where it was believed that a fire started in an overhead locker of an aircraft that had just taken off from New York, was caused by a short-circuited battery in an overhead locker.